error-prone-support/integration-tests/checkstyle-expected-changes.patch

--- a/src/it/java/com/google/checkstyle/test/base/AbstractIndentationTestSupport.java
+++ b/src/it/java/com/google/checkstyle/test/base/AbstractIndentationTestSupport.java
@@ -19,10 +19,12 @@
 
 package com.google.checkstyle.test.base;
 
+import static com.google.common.base.Preconditions.checkState;
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.io.BufferedReader;
 import java.io.IOException;
-import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Paths;
 import java.util.ArrayList;
@@ -71,8 +73,7 @@ public abstract class AbstractIndentationTestSupport extends AbstractGoogleModul
   private static Integer[] getLinesWithWarnAndCheckComments(String aFileName, final int tabWidth)
       throws IOException {
     final List<Integer> result = new ArrayList<>();
-    try (BufferedReader br =
-        Files.newBufferedReader(Paths.get(aFileName), StandardCharsets.UTF_8)) {
+    try (BufferedReader br = Files.newBufferedReader(Paths.get(aFileName), UTF_8)) {
       int lineNumber = 1;
       for (String line = br.readLine(); line != null; line = br.readLine()) {
         final Matcher match = LINE_WITH_COMMENT_REGEX.matcher(line);
@@ -81,30 +82,28 @@ public abstract class AbstractIndentationTestSupport extends AbstractGoogleModul
           final int indentInComment = getIndentFromComment(comment);
           final int actualIndent = getLineStart(line, tabWidth);
 
-          if (actualIndent != indentInComment) {
-            throw new IllegalStateException(
-                String.format(
-                    Locale.ROOT,
-                    "File \"%1$s\" has incorrect indentation in comment."
-                        + "Line %2$d: comment:%3$d, actual:%4$d.",
-                    aFileName,
-                    lineNumber,
-                    indentInComment,
-                    actualIndent));
-          }
+          checkState(
+              actualIndent == indentInComment,
+              String.format(
+                  Locale.ROOT,
+                  "File \"%1$s\" has incorrect indentation in comment."
+                      + "Line %2$d: comment:%3$d, actual:%4$d.",
+                  aFileName,
+                  lineNumber,
+                  indentInComment,
+                  actualIndent));
 
           if (isWarnComment(comment)) {
             result.add(lineNumber);
           }
 
-          if (!isCommentConsistent(comment)) {
-            throw new IllegalStateException(
-                String.format(
-                    Locale.ROOT,
-                    "File \"%1$s\" has inconsistent comment on line %2$d",
-                    aFileName,
-                    lineNumber));
-          }
+          checkState(
+              isCommentConsistent(comment),
+              String.format(
+                  Locale.ROOT,
+                  "File \"%1$s\" has inconsistent comment on line %2$d",
+                  aFileName,
+                  lineNumber));
         } else if (NONEMPTY_LINE_REGEX.matcher(line).matches()) {
           throw new IllegalStateException(
               String.format(
--- a/src/it/java/com/google/checkstyle/test/chapter2filebasic/rule21filename/OuterTypeFilenameTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter2filebasic/rule21filename/OuterTypeFilenameTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.checks.OuterTypeFilenameCheck;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class OuterTypeFilenameTest extends AbstractGoogleModuleTestSupport {
+final class OuterTypeFilenameTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class OuterTypeFilenameTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testOuterTypeFilename1() throws Exception {
+  void outerTypeFilename1() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("OuterTypeFilename");
@@ -46,7 +46,7 @@ public class OuterTypeFilenameTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testOuterTypeFilename2() throws Exception {
+  void outerTypeFilename2() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("OuterTypeFilename");
@@ -57,7 +57,7 @@ public class OuterTypeFilenameTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testOuterTypeFilename3() throws Exception {
+  void outerTypeFilename3() throws Exception {
     final String[] expected = {
       "3:1: " + getCheckMessage(OuterTypeFilenameCheck.class, MSG_KEY),
     };
--- a/src/it/java/com/google/checkstyle/test/chapter2filebasic/rule231filetab/FileTabCharacterTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter2filebasic/rule231filetab/FileTabCharacterTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.FileTabCharacterCheck;
 import org.junit.jupiter.api.Test;
 
-public class FileTabCharacterTest extends AbstractGoogleModuleTestSupport {
+final class FileTabCharacterTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class FileTabCharacterTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testFileTab() throws Exception {
+  void fileTab() throws Exception {
     final String[] expected = {
       "8:25: " + getCheckMessage(FileTabCharacterCheck.class, "containsTab"),
       "51:5: " + getCheckMessage(FileTabCharacterCheck.class, "containsTab"),
--- a/src/it/java/com/google/checkstyle/test/chapter2filebasic/rule232specialescape/IllegalTokenTextTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter2filebasic/rule232specialescape/IllegalTokenTextTest.java
@@ -23,7 +23,7 @@ import com.google.checkstyle.test.base.AbstractGoogleModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.Configuration;
 import org.junit.jupiter.api.Test;
 
-public class IllegalTokenTextTest extends AbstractGoogleModuleTestSupport {
+final class IllegalTokenTextTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -31,7 +31,7 @@ public class IllegalTokenTextTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testIllegalTokens() throws Exception {
+  void illegalTokens() throws Exception {
     final String message =
         "Consider using special escape sequence instead of octal value or "
             + "Unicode escaped value.";
--- a/src/it/java/com/google/checkstyle/test/chapter2filebasic/rule233nonascii/AvoidEscapedUnicodeCharactersTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter2filebasic/rule233nonascii/AvoidEscapedUnicodeCharactersTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.AvoidEscapedUnicodeCharactersCheck;
 import org.junit.jupiter.api.Test;
 
-public class AvoidEscapedUnicodeCharactersTest extends AbstractGoogleModuleTestSupport {
+final class AvoidEscapedUnicodeCharactersTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class AvoidEscapedUnicodeCharactersTest extends AbstractGoogleModuleTestS
   }
 
   @Test
-  public void testUnicodeEscapes() throws Exception {
+  void unicodeEscapes() throws Exception {
     final String[] expected = {
       "5:42: " + getCheckMessage(AvoidEscapedUnicodeCharactersCheck.class, MSG_KEY),
       "15:38: " + getCheckMessage(AvoidEscapedUnicodeCharactersCheck.class, MSG_KEY),
--- a/src/it/java/com/google/checkstyle/test/chapter3filestructure/rule32packagestate/LineLengthTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter3filestructure/rule32packagestate/LineLengthTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.sizes.LineLengthCheck;
 import org.junit.jupiter.api.Test;
 
-public class LineLengthTest extends AbstractGoogleModuleTestSupport {
+final class LineLengthTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class LineLengthTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testLineLength() throws Exception {
+  void lineLength() throws Exception {
     final String[] expected = {
       "5: " + getCheckMessage(LineLengthCheck.class, "maxLineLen", 100, 112),
       "29: " + getCheckMessage(LineLengthCheck.class, "maxLineLen", 100, 183),
--- a/src/it/java/com/google/checkstyle/test/chapter3filestructure/rule331nowildcard/AvoidStarImportTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter3filestructure/rule331nowildcard/AvoidStarImportTest.java
@@ -23,7 +23,7 @@ import com.google.checkstyle.test.base.AbstractGoogleModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.Configuration;
 import org.junit.jupiter.api.Test;
 
-public class AvoidStarImportTest extends AbstractGoogleModuleTestSupport {
+final class AvoidStarImportTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -31,7 +31,7 @@ public class AvoidStarImportTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testStarImport() throws Exception {
+  void starImport() throws Exception {
     final String[] expected = {
       "3:15: Using the '.*' form of import should be avoided - java.io.*.",
       "4:17: Using the '.*' form of import should be avoided - java.lang.*.",
--- a/src/it/java/com/google/checkstyle/test/chapter3filestructure/rule332nolinewrap/NoLineWrapTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter3filestructure/rule332nolinewrap/NoLineWrapTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.checks.whitespace.NoLineWrapCheck;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class NoLineWrapTest extends AbstractGoogleModuleTestSupport {
+final class NoLineWrapTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class NoLineWrapTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testBadLineWrap() throws Exception {
+  void badLineWrap() throws Exception {
     final String[] expected = {
       "1:1: " + getCheckMessage(NoLineWrapCheck.class, "no.line.wrap", "package"),
       "6:1: " + getCheckMessage(NoLineWrapCheck.class, "no.line.wrap", "import"),
@@ -49,7 +49,7 @@ public class NoLineWrapTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testGoodLineWrap() throws Exception {
+  void goodLineWrap() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("NoLineWrap");
@@ -60,7 +60,7 @@ public class NoLineWrapTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void goodLineLength() throws Exception {
+  void goodLineLength() throws Exception {
     final int maxLineLength = 100;
     final String[] expected = {
       "5: " + getCheckMessage(LineLengthCheck.class, "maxLineLen", maxLineLength, 112),
--- a/src/it/java/com/google/checkstyle/test/chapter3filestructure/rule333orderingandspacing/CustomImportOrderTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter3filestructure/rule333orderingandspacing/CustomImportOrderTest.java
@@ -25,7 +25,7 @@ import com.puppycrawl.tools.checkstyle.checks.imports.CustomImportOrderCheck;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class CustomImportOrderTest extends AbstractGoogleModuleTestSupport {
+final class CustomImportOrderTest extends AbstractGoogleModuleTestSupport {
 
   /** Shortcuts to make code more compact. */
   private static final String MSG_LINE_SEPARATOR = CustomImportOrderCheck.MSG_LINE_SEPARATOR;
@@ -45,7 +45,7 @@ public class CustomImportOrderTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testCustomImport1() throws Exception {
+  void customImport1() throws Exception {
     final String[] expected = {
       "4:1: "
           + getCheckMessage(clazz, MSG_LEX, "java.awt.Button.ABORT", "java.io.File.createTempFile"),
@@ -68,7 +68,7 @@ public class CustomImportOrderTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testCustomImport2() throws Exception {
+  void customImport2() throws Exception {
     final String[] expected = {
       "4:1: "
           + getCheckMessage(clazz, MSG_LEX, "java.awt.Button.ABORT", "java.io.File.createTempFile"),
@@ -113,7 +113,7 @@ public class CustomImportOrderTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testCustomImport3() throws Exception {
+  void customImport3() throws Exception {
     final String[] expected = {
       "4:1: " + getCheckMessage(clazz, MSG_LINE_SEPARATOR, "java.awt.Dialog"),
       "5:1: "
@@ -155,7 +155,7 @@ public class CustomImportOrderTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testCustomImport4() throws Exception {
+  void customImport4() throws Exception {
     final String[] expected = {
       "7:1: " + getCheckMessage(clazz, MSG_SEPARATED_IN_GROUP, "javax.swing.WindowConstants.*"),
       "15:1: " + getCheckMessage(clazz, MSG_SEPARATED_IN_GROUP, "java.util.StringTokenizer"),
@@ -172,7 +172,7 @@ public class CustomImportOrderTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testCustomImport5() throws Exception {
+  void customImport5() throws Exception {
     final String[] expected = {
       "9:1: " + getCheckMessage(clazz, MSG_SEPARATED_IN_GROUP, "javax.swing.WindowConstants.*"),
       "13:1: "
@@ -195,7 +195,7 @@ public class CustomImportOrderTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testValid() throws Exception {
+  void valid() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("CustomImportOrder");
@@ -206,7 +206,7 @@ public class CustomImportOrderTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testValid2() throws Exception {
+  void valid2() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("CustomImportOrder");
@@ -217,7 +217,7 @@ public class CustomImportOrderTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testValidGoogleStyleOrderOfImports() throws Exception {
+  void validGoogleStyleOrderOfImports() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("CustomImportOrder");
--- a/src/it/java/com/google/checkstyle/test/chapter3filestructure/rule341onetoplevel/OneTopLevelClassTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter3filestructure/rule341onetoplevel/OneTopLevelClassTest.java
@@ -25,7 +25,7 @@ import com.puppycrawl.tools.checkstyle.checks.design.OneTopLevelClassCheck;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class OneTopLevelClassTest extends AbstractGoogleModuleTestSupport {
+final class OneTopLevelClassTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class OneTopLevelClassTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testBad() throws Exception {
+  void bad() throws Exception {
     final Class<OneTopLevelClassCheck> clazz = OneTopLevelClassCheck.class;
     final String messageKey = "one.top.level.class";
 
@@ -54,7 +54,7 @@ public class OneTopLevelClassTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testGood() throws Exception {
+  void good() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("OneTopLevelClass");
@@ -65,7 +65,7 @@ public class OneTopLevelClassTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testBad1() throws Exception {
+  void bad1() throws Exception {
     final Class<OneTopLevelClassCheck> clazz = OneTopLevelClassCheck.class;
     final String messageKey = "one.top.level.class";
 
@@ -82,7 +82,7 @@ public class OneTopLevelClassTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testBad2() throws Exception {
+  void bad2() throws Exception {
     final Class<OneTopLevelClassCheck> clazz = OneTopLevelClassCheck.class;
     final String messageKey = "one.top.level.class";
 
--- a/src/it/java/com/google/checkstyle/test/chapter3filestructure/rule3421overloadsplit/OverloadMethodsDeclarationOrderTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter3filestructure/rule3421overloadsplit/OverloadMethodsDeclarationOrderTest.java
@@ -25,7 +25,7 @@ import com.puppycrawl.tools.checkstyle.checks.coding.OverloadMethodsDeclarationO
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class OverloadMethodsDeclarationOrderTest extends AbstractGoogleModuleTestSupport {
+final class OverloadMethodsDeclarationOrderTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class OverloadMethodsDeclarationOrderTest extends AbstractGoogleModuleTes
   }
 
   @Test
-  public void testOverloadMethods() throws Exception {
+  void overloadMethods() throws Exception {
     final Class<OverloadMethodsDeclarationOrderCheck> clazz =
         OverloadMethodsDeclarationOrderCheck.class;
     final String messageKey = "overload.methods.declaration";
@@ -53,7 +53,7 @@ public class OverloadMethodsDeclarationOrderTest extends AbstractGoogleModuleTes
   }
 
   @Test
-  public void testOverloadMethodsDeclarationOrderPrivateAndStaticMethods() throws Exception {
+  void overloadMethodsDeclarationOrderPrivateAndStaticMethods() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
--- a/src/it/java/com/google/checkstyle/test/chapter3filestructure/rule3sourcefile/EmptyLineSeparatorTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter3filestructure/rule3sourcefile/EmptyLineSeparatorTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.EmptyLineSeparatorCheck;
 import org.junit.jupiter.api.Test;
 
-public class EmptyLineSeparatorTest extends AbstractGoogleModuleTestSupport {
+final class EmptyLineSeparatorTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class EmptyLineSeparatorTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testEmptyLineSeparator() throws Exception {
+  void emptyLineSeparator() throws Exception {
     final Class<EmptyLineSeparatorCheck> clazz = EmptyLineSeparatorCheck.class;
     final String messageKey = "empty.line.separator";
 
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule411bracesareused/NeedBracesTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule411bracesareused/NeedBracesTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.blocks.NeedBracesCheck;
 import org.junit.jupiter.api.Test;
 
-public class NeedBracesTest extends AbstractGoogleModuleTestSupport {
+final class NeedBracesTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class NeedBracesTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testNeedBraces() throws Exception {
+  void needBraces() throws Exception {
     final Class<NeedBracesCheck> clazz = NeedBracesCheck.class;
     final String messageKey = "needBraces";
 
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule412nonemptyblocks/LeftCurlyTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule412nonemptyblocks/LeftCurlyTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.blocks.LeftCurlyCheck;
 import org.junit.jupiter.api.Test;
 
-public class LeftCurlyTest extends AbstractGoogleModuleTestSupport {
+final class LeftCurlyTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class LeftCurlyTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testLeftCurlyBraces() throws Exception {
+  void leftCurlyBraces() throws Exception {
     final String[] expected = {
       "4:1: " + getCheckMessage(LeftCurlyCheck.class, MSG_KEY_LINE_PREVIOUS, "{", 1),
       "7:5: " + getCheckMessage(LeftCurlyCheck.class, MSG_KEY_LINE_PREVIOUS, "{", 5),
@@ -53,7 +53,7 @@ public class LeftCurlyTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testLeftCurlyAnnotations() throws Exception {
+  void leftCurlyAnnotations() throws Exception {
     final String[] expected = {
       "10:1: " + getCheckMessage(LeftCurlyCheck.class, MSG_KEY_LINE_PREVIOUS, "{", 1),
       "14:5: " + getCheckMessage(LeftCurlyCheck.class, MSG_KEY_LINE_PREVIOUS, "{", 5),
@@ -70,7 +70,7 @@ public class LeftCurlyTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testLeftCurlyMethods() throws Exception {
+  void leftCurlyMethods() throws Exception {
     final String[] expected = {
       "4:1: " + getCheckMessage(LeftCurlyCheck.class, MSG_KEY_LINE_PREVIOUS, "{", 1),
       "9:5: " + getCheckMessage(LeftCurlyCheck.class, MSG_KEY_LINE_PREVIOUS, "{", 5),
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule412nonemptyblocks/RightCurlyTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule412nonemptyblocks/RightCurlyTest.java
@@ -29,7 +29,7 @@ import com.puppycrawl.tools.checkstyle.checks.blocks.RightCurlyCheck;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class RightCurlyTest extends AbstractGoogleModuleTestSupport {
+final class RightCurlyTest extends AbstractGoogleModuleTestSupport {
 
   private static final String[] MODULES = {
     "RightCurlySame", "RightCurlyAlone",
@@ -41,7 +41,7 @@ public class RightCurlyTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testRightCurly() throws Exception {
+  void rightCurly() throws Exception {
     final String[] expected = {
       "20:17: " + getCheckMessage(RightCurlyCheck.class, MSG_KEY_LINE_SAME, "}", 17),
       "32:13: " + getCheckMessage(RightCurlyCheck.class, MSG_KEY_LINE_SAME, "}", 13),
@@ -58,7 +58,7 @@ public class RightCurlyTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testRightCurly2() throws Exception {
+  void rightCurly2() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = createTreeWalkerConfig(getModuleConfigsByIds(MODULES));
@@ -69,7 +69,7 @@ public class RightCurlyTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testRightCurlyLiteralDoDefault() throws Exception {
+  void rightCurlyLiteralDoDefault() throws Exception {
     final String[] expected = {
       "62:9: " + getCheckMessage(RightCurlyCheck.class, MSG_KEY_LINE_SAME, "}", 9),
       "67:13: " + getCheckMessage(RightCurlyCheck.class, MSG_KEY_LINE_SAME, "}", 13),
@@ -84,7 +84,7 @@ public class RightCurlyTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testRightCurlyOther() throws Exception {
+  void rightCurlyOther() throws Exception {
     final String[] expected = {
       "20:17: " + getCheckMessage(RightCurlyCheck.class, MSG_KEY_LINE_SAME, "}", 17),
       "32:13: " + getCheckMessage(RightCurlyCheck.class, MSG_KEY_LINE_SAME, "}", 13),
@@ -101,7 +101,7 @@ public class RightCurlyTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testRightCurlyLiteralDo() throws Exception {
+  void rightCurlyLiteralDo() throws Exception {
     final String[] expected = {
       "62:9: " + getCheckMessage(RightCurlyCheck.class, MSG_KEY_LINE_SAME, "}", 9),
       "67:13: " + getCheckMessage(RightCurlyCheck.class, MSG_KEY_LINE_SAME, "}", 13),
@@ -116,7 +116,7 @@ public class RightCurlyTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testRightCurlySwitch() throws Exception {
+  void rightCurlySwitch() throws Exception {
     final String[] expected = {
       "12:24: " + getCheckMessage(RightCurlyCheck.class, MSG_KEY_LINE_ALONE, "}", 24),
       "19:27: " + getCheckMessage(RightCurlyCheck.class, MSG_KEY_LINE_ALONE, "}", 27),
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule413emptyblocks/EmptyBlockTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule413emptyblocks/EmptyBlockTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.blocks.EmptyBlockCheck;
 import org.junit.jupiter.api.Test;
 
-public class EmptyBlockTest extends AbstractGoogleModuleTestSupport {
+final class EmptyBlockTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class EmptyBlockTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testEmptyBlock() throws Exception {
+  void emptyBlock() throws Exception {
     final String[] expected = {
       "19:21: " + getCheckMessage(EmptyBlockCheck.class, "block.empty", "if"),
       "22:34: " + getCheckMessage(EmptyBlockCheck.class, "block.empty", "if"),
@@ -77,7 +77,7 @@ public class EmptyBlockTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testEmptyBlockCatch() throws Exception {
+  void emptyBlockCatch() throws Exception {
     final String[] expected = {
       "29:17: " + getCheckMessage(EmptyBlockCheck.class, "block.empty", "finally"),
       "50:21: " + getCheckMessage(EmptyBlockCheck.class, "block.empty", "finally"),
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule413emptyblocks/EmptyCatchBlockTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule413emptyblocks/EmptyCatchBlockTest.java
@@ -25,7 +25,7 @@ import com.puppycrawl.tools.checkstyle.checks.blocks.EmptyCatchBlockCheck;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class EmptyCatchBlockTest extends AbstractGoogleModuleTestSupport {
+final class EmptyCatchBlockTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class EmptyCatchBlockTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testEmptyBlockCatch() throws Exception {
+  void emptyBlockCatch() throws Exception {
     final String[] expected = {
       "28:31: " + getCheckMessage(EmptyCatchBlockCheck.class, "catch.block.empty"),
       "49:35: " + getCheckMessage(EmptyCatchBlockCheck.class, "catch.block.empty"),
@@ -50,7 +50,7 @@ public class EmptyCatchBlockTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testNoViolations() throws Exception {
+  void noViolations() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("EmptyCatchBlock");
@@ -61,7 +61,7 @@ public class EmptyCatchBlockTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testViolationsByComment() throws Exception {
+  void violationsByComment() throws Exception {
     final String[] expected = {
       "20:9: " + getCheckMessage(EmptyCatchBlockCheck.class, "catch.block.empty"),
       "28:18: " + getCheckMessage(EmptyCatchBlockCheck.class, "catch.block.empty"),
@@ -75,7 +75,7 @@ public class EmptyCatchBlockTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testViolationsByVariableName() throws Exception {
+  void violationsByVariableName() throws Exception {
     final String[] expected = {
       "20:9: " + getCheckMessage(EmptyCatchBlockCheck.class, "catch.block.empty"),
       "36:18: " + getCheckMessage(EmptyCatchBlockCheck.class, "catch.block.empty"),
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule43onestatement/OneStatementPerLineTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule43onestatement/OneStatementPerLineTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.coding.OneStatementPerLineCheck;
 import org.junit.jupiter.api.Test;
 
-public class OneStatementPerLineTest extends AbstractGoogleModuleTestSupport {
+final class OneStatementPerLineTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class OneStatementPerLineTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testOneStatement() throws Exception {
+  void oneStatement() throws Exception {
     final String msg = getCheckMessage(OneStatementPerLineCheck.class, "multiple.statements.line");
 
     final String[] expected = {
@@ -67,7 +67,7 @@ public class OneStatementPerLineTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testOneStatementNonCompilableInput() throws Exception {
+  void oneStatementNonCompilableInput() throws Exception {
     final String msg = getCheckMessage(OneStatementPerLineCheck.class, "multiple.statements.line");
 
     final String[] expected = {
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule44columnlimit/LineLengthTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule44columnlimit/LineLengthTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.sizes.LineLengthCheck;
 import org.junit.jupiter.api.Test;
 
-public class LineLengthTest extends AbstractGoogleModuleTestSupport {
+final class LineLengthTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class LineLengthTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testLineLength() throws Exception {
+  void lineLength() throws Exception {
     final String[] expected = {
       "5: " + getCheckMessage(LineLengthCheck.class, "maxLineLen", 100, 112),
       "29: " + getCheckMessage(LineLengthCheck.class, "maxLineLen", 100, 113),
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule451wheretobreak/MethodParamPadTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule451wheretobreak/MethodParamPadTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.MethodParamPadCheck;
 import org.junit.jupiter.api.Test;
 
-public class MethodParamPadTest extends AbstractGoogleModuleTestSupport {
+final class MethodParamPadTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class MethodParamPadTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testOperatorWrap() throws Exception {
+  void operatorWrap() throws Exception {
     final Class<MethodParamPadCheck> clazz = MethodParamPadCheck.class;
     final String messageKeyPrevious = "line.previous";
     final String messageKeyPreceded = "ws.preceded";
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule451wheretobreak/OperatorWrapTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule451wheretobreak/OperatorWrapTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.OperatorWrapCheck;
 import org.junit.jupiter.api.Test;
 
-public class OperatorWrapTest extends AbstractGoogleModuleTestSupport {
+final class OperatorWrapTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class OperatorWrapTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testOperatorWrap() throws Exception {
+  void operatorWrap() throws Exception {
     final Class<OperatorWrapCheck> clazz = OperatorWrapCheck.class;
     final String messageKey = "line.new";
 
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule451wheretobreak/SeparatorWrapTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule451wheretobreak/SeparatorWrapTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.SeparatorWrapCheck;
 import org.junit.jupiter.api.Test;
 
-public class SeparatorWrapTest extends AbstractGoogleModuleTestSupport {
+final class SeparatorWrapTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class SeparatorWrapTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testSeparatorWrapDot() throws Exception {
+  void separatorWrapDot() throws Exception {
     final String[] expected = {
       "28:30: " + getCheckMessage(SeparatorWrapCheck.class, "line.new", "."),
     };
@@ -47,7 +47,7 @@ public class SeparatorWrapTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testSeparatorWrapComma() throws Exception {
+  void separatorWrapComma() throws Exception {
     final String[] expected = {
       "31:17: " + getCheckMessage(SeparatorWrapCheck.class, "line.previous", ","),
     };
@@ -60,7 +60,7 @@ public class SeparatorWrapTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testSeparatorWrapMethodRef() throws Exception {
+  void separatorWrapMethodRef() throws Exception {
     final String[] expected = {
       "17:49: " + getCheckMessage(SeparatorWrapCheck.class, MSG_LINE_NEW, "::"),
     };
@@ -73,7 +73,7 @@ public class SeparatorWrapTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testEllipsis() throws Exception {
+  void ellipsis() throws Exception {
     final String[] expected = {
       "11:13: " + getCheckMessage(SeparatorWrapCheck.class, "line.previous", "..."),
     };
@@ -86,7 +86,7 @@ public class SeparatorWrapTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testArrayDeclarator() throws Exception {
+  void arrayDeclarator() throws Exception {
     final String[] expected = {
       "9:13: " + getCheckMessage(SeparatorWrapCheck.class, "line.previous", "["),
     };
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule461verticalwhitespace/EmptyLineSeparatorTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule461verticalwhitespace/EmptyLineSeparatorTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.EmptyLineSeparatorCheck;
 import org.junit.jupiter.api.Test;
 
-public class EmptyLineSeparatorTest extends AbstractGoogleModuleTestSupport {
+final class EmptyLineSeparatorTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class EmptyLineSeparatorTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testEmptyLineSeparator() throws Exception {
+  void emptyLineSeparator() throws Exception {
     final Class<EmptyLineSeparatorCheck> clazz = EmptyLineSeparatorCheck.class;
     final String messageKey = "empty.line.separator";
 
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule462horizontalwhitespace/GenericWhitespaceTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule462horizontalwhitespace/GenericWhitespaceTest.java
@@ -25,7 +25,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
 
-public class GenericWhitespaceTest extends AbstractGoogleModuleTestSupport {
+final class GenericWhitespaceTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class GenericWhitespaceTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testWhitespaceAroundGenerics() throws Exception {
+  void whitespaceAroundGenerics() throws Exception {
     final String msgPreceded = "ws.preceded";
     final String msgFollowed = "ws.followed";
     final Configuration checkConfig = getModuleConfig("GenericWhitespace");
@@ -65,7 +65,7 @@ public class GenericWhitespaceTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testGenericWhitespace() throws Exception {
+  void genericWhitespace() throws Exception {
     final String msgPreceded = "ws.preceded";
     final String msgFollowed = "ws.followed";
     final String msgNotPreceded = "ws.notPreceded";
@@ -109,7 +109,7 @@ public class GenericWhitespaceTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void genericEndsTheLine() throws Exception {
+  void genericEndsTheLine() throws Exception {
     final Configuration checkConfig = getModuleConfig("GenericWhitespace");
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verify(checkConfig, getPath("InputGenericWhitespaceEndsTheLine.java"), expected);
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule462horizontalwhitespace/MethodParamPadTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule462horizontalwhitespace/MethodParamPadTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.MethodParamPadCheck;
 import org.junit.jupiter.api.Test;
 
-public class MethodParamPadTest extends AbstractGoogleModuleTestSupport {
+final class MethodParamPadTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class MethodParamPadTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testOperatorWrap() throws Exception {
+  void operatorWrap() throws Exception {
     final Class<MethodParamPadCheck> clazz = MethodParamPadCheck.class;
     final String messageKeyPreceded = "ws.preceded";
 
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule462horizontalwhitespace/NoWhitespaceBeforeCaseDefaultColonTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule462horizontalwhitespace/NoWhitespaceBeforeCaseDefaultColonTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.NoWhitespaceBeforeCheck;
 import org.junit.jupiter.api.Test;
 
-public class NoWhitespaceBeforeCaseDefaultColonTest extends AbstractGoogleModuleTestSupport {
+final class NoWhitespaceBeforeCaseDefaultColonTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class NoWhitespaceBeforeCaseDefaultColonTest extends AbstractGoogleModule
   }
 
   @Test
-  public void test() throws Exception {
+  void test() throws Exception {
     final Class<NoWhitespaceBeforeCheck> clazz = NoWhitespaceBeforeCheck.class;
     final String messageKeyPreceded = "ws.preceded";
 
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule462horizontalwhitespace/NoWhitespaceBeforeTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule462horizontalwhitespace/NoWhitespaceBeforeTest.java
@@ -25,7 +25,7 @@ import com.puppycrawl.tools.checkstyle.checks.whitespace.NoWhitespaceBeforeCheck
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class NoWhitespaceBeforeTest extends AbstractGoogleModuleTestSupport {
+final class NoWhitespaceBeforeTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class NoWhitespaceBeforeTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testEmptyForLoop() throws Exception {
+  void emptyForLoop() throws Exception {
     final Class<NoWhitespaceBeforeCheck> clazz = NoWhitespaceBeforeCheck.class;
     final String messageKeyPreceded = "ws.preceded";
 
@@ -49,7 +49,7 @@ public class NoWhitespaceBeforeTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testColonOfLabel() throws Exception {
+  void colonOfLabel() throws Exception {
     final Class<NoWhitespaceBeforeCheck> clazz = NoWhitespaceBeforeCheck.class;
     final String messageKeyPreceded = "ws.preceded";
 
@@ -64,7 +64,7 @@ public class NoWhitespaceBeforeTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testAnnotations() throws Exception {
+  void annotations() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     final Configuration checkConfig = getModuleConfig("NoWhitespaceBefore");
     final String filePath = getPath("InputNoWhitespaceBeforeAnnotations.java");
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule462horizontalwhitespace/ParenPadTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule462horizontalwhitespace/ParenPadTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.ParenPadCheck;
 import org.junit.jupiter.api.Test;
 
-public class ParenPadTest extends AbstractGoogleModuleTestSupport {
+final class ParenPadTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class ParenPadTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testMethodParen() throws Exception {
+  void methodParen() throws Exception {
     final Class<ParenPadCheck> clazz = ParenPadCheck.class;
     final String messageKeyPreceded = "ws.preceded";
     final String messageKeyFollowed = "ws.followed";
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule462horizontalwhitespace/WhitespaceAfterTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule462horizontalwhitespace/WhitespaceAfterTest.java
@@ -25,7 +25,7 @@ import com.puppycrawl.tools.checkstyle.checks.whitespace.WhitespaceAfterCheck;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class WhitespaceAfterTest extends AbstractGoogleModuleTestSupport {
+final class WhitespaceAfterTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class WhitespaceAfterTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testWhitespaceAfterBad() throws Exception {
+  void whitespaceAfterBad() throws Exception {
     final Class<WhitespaceAfterCheck> clazz = WhitespaceAfterCheck.class;
     final String message = "ws.notFollowed";
 
@@ -70,7 +70,7 @@ public class WhitespaceAfterTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testWhitespaceAfterGood() throws Exception {
+  void whitespaceAfterGood() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     final Configuration checkConfig = getModuleConfig("WhitespaceAfter");
     final String filePath = getPath("InputWhitespaceAfterGood.java");
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule462horizontalwhitespace/WhitespaceAroundTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule462horizontalwhitespace/WhitespaceAroundTest.java
@@ -25,7 +25,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
 
-public class WhitespaceAroundTest extends AbstractGoogleModuleTestSupport {
+final class WhitespaceAroundTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class WhitespaceAroundTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testWhitespaceAroundBasic() throws Exception {
+  void whitespaceAroundBasic() throws Exception {
     final Configuration checkConfig = getModuleConfig("WhitespaceAround");
     final String msgPreceded = "ws.notPreceded";
     final String msgFollowed = "ws.notFollowed";
@@ -75,7 +75,7 @@ public class WhitespaceAroundTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testWhitespaceAroundEmptyTypesCycles() throws Exception {
+  void whitespaceAroundEmptyTypesCycles() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("WhitespaceAround");
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule4821onevariableperline/MultipleVariableDeclarationsTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule4821onevariableperline/MultipleVariableDeclarationsTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.coding.MultipleVariableDeclarationsCheck;
 import org.junit.jupiter.api.Test;
 
-public class MultipleVariableDeclarationsTest extends AbstractGoogleModuleTestSupport {
+final class MultipleVariableDeclarationsTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class MultipleVariableDeclarationsTest extends AbstractGoogleModuleTestSu
   }
 
   @Test
-  public void testMultipleVariableDeclarations() throws Exception {
+  void multipleVariableDeclarations() throws Exception {
     final String msgComma =
         getCheckMessage(
             MultipleVariableDeclarationsCheck.class, "multiple.variable.declarations.comma");
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule4822variabledistance/VariableDeclarationUsageDistanceTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule4822variabledistance/VariableDeclarationUsageDistanceTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.coding.VariableDeclarationUsageDistanceCheck;
 import org.junit.jupiter.api.Test;
 
-public class VariableDeclarationUsageDistanceTest extends AbstractGoogleModuleTestSupport {
+final class VariableDeclarationUsageDistanceTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class VariableDeclarationUsageDistanceTest extends AbstractGoogleModuleTe
   }
 
   @Test
-  public void testArrayTypeStyle() throws Exception {
+  void arrayTypeStyle() throws Exception {
     final String msgExt = "variable.declaration.usage.distance.extend";
     final Class<VariableDeclarationUsageDistanceCheck> clazz =
         VariableDeclarationUsageDistanceCheck.class;
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule4832nocstylearray/ArrayTypeStyleTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule4832nocstylearray/ArrayTypeStyleTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.ArrayTypeStyleCheck;
 import org.junit.jupiter.api.Test;
 
-public class ArrayTypeStyleTest extends AbstractGoogleModuleTestSupport {
+final class ArrayTypeStyleTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class ArrayTypeStyleTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testArrayTypeStyle() throws Exception {
+  void arrayTypeStyle() throws Exception {
     final String[] expected = {
       "9:23: " + getCheckMessage(ArrayTypeStyleCheck.class, MSG_KEY),
       "15:44: " + getCheckMessage(ArrayTypeStyleCheck.class, MSG_KEY),
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule4841indentation/IndentationTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule4841indentation/IndentationTest.java
@@ -28,7 +28,7 @@ import com.puppycrawl.tools.checkstyle.checks.indentation.IndentationCheck;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class IndentationTest extends AbstractIndentationTestSupport {
+final class IndentationTest extends AbstractIndentationTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -36,7 +36,7 @@ public class IndentationTest extends AbstractIndentationTestSupport {
   }
 
   @Test
-  public void testCorrectClass() throws Exception {
+  void correctClass() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("Indentation");
@@ -47,7 +47,7 @@ public class IndentationTest extends AbstractIndentationTestSupport {
   }
 
   @Test
-  public void testCorrectField() throws Exception {
+  void correctField() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("Indentation");
@@ -58,7 +58,7 @@ public class IndentationTest extends AbstractIndentationTestSupport {
   }
 
   @Test
-  public void testCorrectFor() throws Exception {
+  void correctFor() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("Indentation");
@@ -69,7 +69,7 @@ public class IndentationTest extends AbstractIndentationTestSupport {
   }
 
   @Test
-  public void testCorrectIf() throws Exception {
+  void correctIf() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("Indentation");
@@ -80,7 +80,7 @@ public class IndentationTest extends AbstractIndentationTestSupport {
   }
 
   @Test
-  public void testCorrectNewKeyword() throws Exception {
+  void correctNewKeyword() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("Indentation");
@@ -91,7 +91,7 @@ public class IndentationTest extends AbstractIndentationTestSupport {
   }
 
   @Test
-  public void testCorrect() throws Exception {
+  void correct() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("Indentation");
@@ -102,7 +102,7 @@ public class IndentationTest extends AbstractIndentationTestSupport {
   }
 
   @Test
-  public void testCorrectReturn() throws Exception {
+  void correctReturn() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("Indentation");
@@ -113,7 +113,7 @@ public class IndentationTest extends AbstractIndentationTestSupport {
   }
 
   @Test
-  public void testCorrectWhile() throws Exception {
+  void correctWhile() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("Indentation");
@@ -124,7 +124,7 @@ public class IndentationTest extends AbstractIndentationTestSupport {
   }
 
   @Test
-  public void testCorrectChained() throws Exception {
+  void correctChained() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("Indentation");
@@ -135,7 +135,7 @@ public class IndentationTest extends AbstractIndentationTestSupport {
   }
 
   @Test
-  public void testWarnChained() throws Exception {
+  void warnChained() throws Exception {
     final String[] expected = {
       "18:5: " + getCheckMessage(IndentationCheck.class, MSG_CHILD_ERROR, "method call", 4, 8),
       "23:5: " + getCheckMessage(IndentationCheck.class, MSG_ERROR, ".", 4, 8),
@@ -151,7 +151,7 @@ public class IndentationTest extends AbstractIndentationTestSupport {
   }
 
   @Test
-  public void testCorrectAnnotationArrayInit() throws Exception {
+  void correctAnnotationArrayInit() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("Indentation");
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule4842fallthrough/FallThroughTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule4842fallthrough/FallThroughTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.coding.FallThroughCheck;
 import org.junit.jupiter.api.Test;
 
-public class FallThroughTest extends AbstractGoogleModuleTestSupport {
+final class FallThroughTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class FallThroughTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testFallThrough() throws Exception {
+  void fallThrough() throws Exception {
     final String msg = getCheckMessage(FallThroughCheck.class, "fall.through");
 
     final String[] expected = {
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule4843defaultcasepresent/MissingSwitchDefaultTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule4843defaultcasepresent/MissingSwitchDefaultTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.coding.MissingSwitchDefaultCheck;
 import org.junit.jupiter.api.Test;
 
-public class MissingSwitchDefaultTest extends AbstractGoogleModuleTestSupport {
+final class MissingSwitchDefaultTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class MissingSwitchDefaultTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testMissingSwitchDefault() throws Exception {
+  void missingSwitchDefault() throws Exception {
     final String msg = getCheckMessage(MissingSwitchDefaultCheck.class, "missing.switch.default");
 
     final String[] expected = {
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule485annotations/AnnotationLocationTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule485annotations/AnnotationLocationTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.annotation.AnnotationLocationCheck;
 import org.junit.jupiter.api.Test;
 
-public class AnnotationLocationTest extends AbstractGoogleModuleTestSupport {
+final class AnnotationLocationTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class AnnotationLocationTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testAnnotation() throws Exception {
+  void annotation() throws Exception {
     final Class<AnnotationLocationCheck> clazz = AnnotationLocationCheck.class;
     getCheckMessage(clazz, "annotation.location.alone");
     final Configuration checkConfig =
@@ -62,7 +62,7 @@ public class AnnotationLocationTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationVariables() throws Exception {
+  void annotationVariables() throws Exception {
     final Class<AnnotationLocationCheck> clazz = AnnotationLocationCheck.class;
     getCheckMessage(clazz, "annotation.location.alone");
     final Configuration checkConfig =
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule4861blockcommentstyle/CommentsIndentationTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule4861blockcommentstyle/CommentsIndentationTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.indentation.CommentsIndentationCheck;
 import org.junit.jupiter.api.Test;
 
-public class CommentsIndentationTest extends AbstractGoogleModuleTestSupport {
+final class CommentsIndentationTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class CommentsIndentationTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testCommentIsAtTheEndOfBlock() throws Exception {
+  void commentIsAtTheEndOfBlock() throws Exception {
     final String[] expected = {
       "18:26: "
           + getCheckMessage(
@@ -125,7 +125,7 @@ public class CommentsIndentationTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testCommentIsInsideSwitchBlock() throws Exception {
+  void commentIsInsideSwitchBlock() throws Exception {
     final String[] expected = {
       "19:13: "
           + getCheckMessage(
@@ -228,7 +228,7 @@ public class CommentsIndentationTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testCommentIsInsideEmptyBlock() throws Exception {
+  void commentIsInsideEmptyBlock() throws Exception {
     final String[] expected = {
       "9:20: "
           + getCheckMessage(
@@ -255,7 +255,7 @@ public class CommentsIndentationTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testSurroundingCode() throws Exception {
+  void surroundingCode() throws Exception {
     final String[] expected = {
       "13:15: "
           + getCheckMessage(
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule487modifiers/ModifierOrderTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule487modifiers/ModifierOrderTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.modifier.ModifierOrderCheck;
 import org.junit.jupiter.api.Test;
 
-public class ModifierOrderTest extends AbstractGoogleModuleTestSupport {
+final class ModifierOrderTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class ModifierOrderTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testModifierOrder() throws Exception {
+  void modifierOrder() throws Exception {
     final Class<ModifierOrderCheck> clazz = ModifierOrderCheck.class;
     final String msgMod = "mod.order";
     final String msgAnnotation = "annotation.order";
--- a/src/it/java/com/google/checkstyle/test/chapter4formatting/rule488numericliterals/UpperEllTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter4formatting/rule488numericliterals/UpperEllTest.java
@@ -23,7 +23,7 @@ import com.google.checkstyle.test.base.AbstractGoogleModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.Configuration;
 import org.junit.jupiter.api.Test;
 
-public class UpperEllTest extends AbstractGoogleModuleTestSupport {
+final class UpperEllTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -31,7 +31,7 @@ public class UpperEllTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testUpperEll() throws Exception {
+  void upperEll() throws Exception {
     final String[] expected = {
       "6:33: Should use uppercase 'L'.",
       "12:25: Should use uppercase 'L'.",
--- a/src/it/java/com/google/checkstyle/test/chapter5naming/rule51identifiernames/CatchParameterNameTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter5naming/rule51identifiernames/CatchParameterNameTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
 
-public class CatchParameterNameTest extends AbstractGoogleModuleTestSupport {
+final class CatchParameterNameTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class CatchParameterNameTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testCatchParameterName() throws Exception {
+  void catchParameterName() throws Exception {
     final String msgKey = "name.invalidPattern";
     final Configuration checkConfig = getModuleConfig("CatchParameterName");
     final String format = checkConfig.getProperty("format");
--- a/src/it/java/com/google/checkstyle/test/chapter5naming/rule521packagenames/PackageNameTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter5naming/rule521packagenames/PackageNameTest.java
@@ -26,7 +26,7 @@ import java.io.File;
 import java.io.IOException;
 import org.junit.jupiter.api.Test;
 
-public class PackageNameTest extends AbstractGoogleModuleTestSupport {
+final class PackageNameTest extends AbstractGoogleModuleTestSupport {
 
   private static final String MSG_KEY = "name.invalidPattern";
 
@@ -40,7 +40,7 @@ public class PackageNameTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testGoodPackageName() throws Exception {
+  void goodPackageName() throws Exception {
     final Configuration checkConfig = getModuleConfig("PackageName");
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -51,7 +51,7 @@ public class PackageNameTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testBadPackageName() throws Exception {
+  void badPackageName() throws Exception {
     final String packagePath =
         "com.google.checkstyle.test.chapter5naming.rule521packageNamesCamelCase";
     final Configuration checkConfig = getModuleConfig("PackageName");
@@ -69,7 +69,7 @@ public class PackageNameTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testBadPackageName2() throws Exception {
+  void badPackageName2() throws Exception {
     final String packagePath = "com.google.checkstyle.test.chapter5naming.rule521_packagenames";
     final Configuration checkConfig = getModuleConfig("PackageName");
     final String format = checkConfig.getProperty("format");
@@ -86,7 +86,7 @@ public class PackageNameTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testBadPackageName3() throws Exception {
+  void badPackageName3() throws Exception {
     final String packagePath = "com.google.checkstyle.test.chapter5naming.rule521$packagenames";
     final Configuration checkConfig = getModuleConfig("PackageName");
     final String format = checkConfig.getProperty("format");
--- a/src/it/java/com/google/checkstyle/test/chapter5naming/rule522typenames/TypeNameTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter5naming/rule522typenames/TypeNameTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
 
-public class TypeNameTest extends AbstractGoogleModuleTestSupport {
+final class TypeNameTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class TypeNameTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testTypeName() throws Exception {
+  void typeName() throws Exception {
     final Configuration checkConfig = getModuleConfig("TypeName");
     final String msgKey = "name.invalidPattern";
     final String format = "^[A-Z][a-zA-Z0-9]*$";
--- a/src/it/java/com/google/checkstyle/test/chapter5naming/rule523methodnames/MethodNameTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter5naming/rule523methodnames/MethodNameTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
 
-public class MethodNameTest extends AbstractGoogleModuleTestSupport {
+final class MethodNameTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class MethodNameTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testMethodName() throws Exception {
+  void methodName() throws Exception {
     final Configuration checkConfig = getModuleConfig("MethodName");
     final String msgKey = "name.invalidPattern";
     final String format = "^[a-z][a-z0-9]\\w*$";
--- a/src/it/java/com/google/checkstyle/test/chapter5naming/rule525nonconstantfieldnames/MemberNameTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter5naming/rule525nonconstantfieldnames/MemberNameTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
 
-public class MemberNameTest extends AbstractGoogleModuleTestSupport {
+final class MemberNameTest extends AbstractGoogleModuleTestSupport {
 
   private static final String MSG_KEY = "name.invalidPattern";
 
@@ -34,7 +34,7 @@ public class MemberNameTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testMemberName() throws Exception {
+  void memberName() throws Exception {
     final Configuration checkConfig = getModuleConfig("MemberName");
     final String format = checkConfig.getProperty("format");
     final Map<String, String> messages = checkConfig.getMessages();
@@ -61,7 +61,7 @@ public class MemberNameTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testSimple() throws Exception {
+  void simple() throws Exception {
     final Configuration checkConfig = getModuleConfig("MemberName");
     final String format = checkConfig.getProperty("format");
     final Map<String, String> messages = checkConfig.getMessages();
--- a/src/it/java/com/google/checkstyle/test/chapter5naming/rule526parameternames/LambdaParameterNameTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter5naming/rule526parameternames/LambdaParameterNameTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
 
-public class LambdaParameterNameTest extends AbstractGoogleModuleTestSupport {
+final class LambdaParameterNameTest extends AbstractGoogleModuleTestSupport {
 
   public static final String MSG_INVALID_PATTERN = "name.invalidPattern";
 
@@ -34,7 +34,7 @@ public class LambdaParameterNameTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testLambdaParameterName() throws Exception {
+  void lambdaParameterName() throws Exception {
     final Configuration config = getModuleConfig("LambdaParameterName");
     final String format = config.getProperty("format");
     final Map<String, String> messages = config.getMessages();
--- a/src/it/java/com/google/checkstyle/test/chapter5naming/rule526parameternames/ParameterNameTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter5naming/rule526parameternames/ParameterNameTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
 
-public class ParameterNameTest extends AbstractGoogleModuleTestSupport {
+final class ParameterNameTest extends AbstractGoogleModuleTestSupport {
 
   private static final String MSG_KEY = "name.invalidPattern";
 
@@ -34,7 +34,7 @@ public class ParameterNameTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testGeneralParameterName() throws Exception {
+  void generalParameterName() throws Exception {
     final Configuration config = getModuleConfig("ParameterName");
     final String format = config.getProperty("format");
     final Map<String, String> messages = config.getMessages();
--- a/src/it/java/com/google/checkstyle/test/chapter5naming/rule526parameternames/RecordComponentNameTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter5naming/rule526parameternames/RecordComponentNameTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
 
-public class RecordComponentNameTest extends AbstractGoogleModuleTestSupport {
+final class RecordComponentNameTest extends AbstractGoogleModuleTestSupport {
 
   private static final String MSG_KEY = "name.invalidPattern";
 
@@ -34,7 +34,7 @@ public class RecordComponentNameTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testGeneralParameterName() throws Exception {
+  void generalParameterName() throws Exception {
     final Configuration config = getModuleConfig("RecordComponentName");
     final String format = config.getProperty("format");
     final Map<String, String> messages = config.getMessages();
--- a/src/it/java/com/google/checkstyle/test/chapter5naming/rule527localvariablenames/LocalVariableNameTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter5naming/rule527localvariablenames/LocalVariableNameTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
 
-public class LocalVariableNameTest extends AbstractGoogleModuleTestSupport {
+final class LocalVariableNameTest extends AbstractGoogleModuleTestSupport {
 
   private static final String MSG_KEY = "name.invalidPattern";
 
@@ -34,7 +34,7 @@ public class LocalVariableNameTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testLocalVariableName() throws Exception {
+  void localVariableName() throws Exception {
     final Configuration checkConfig = getModuleConfig("LocalVariableName");
     final String format = checkConfig.getProperty("format");
     final Map<String, String> messages = checkConfig.getMessages();
@@ -58,7 +58,7 @@ public class LocalVariableNameTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testOneChar() throws Exception {
+  void oneChar() throws Exception {
     final Configuration checkConfig = getModuleConfig("LocalVariableName");
     final String format = checkConfig.getProperty("format");
     final Map<String, String> messages = checkConfig.getMessages();
--- a/src/it/java/com/google/checkstyle/test/chapter5naming/rule527localvariablenames/PatternVariableNameTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter5naming/rule527localvariablenames/PatternVariableNameTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
 
-public class PatternVariableNameTest extends AbstractGoogleModuleTestSupport {
+final class PatternVariableNameTest extends AbstractGoogleModuleTestSupport {
 
   private static final String MSG_KEY = "name.invalidPattern";
 
@@ -34,7 +34,7 @@ public class PatternVariableNameTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testPatternVariableName() throws Exception {
+  void patternVariableName() throws Exception {
     final Configuration checkConfig = getModuleConfig("PatternVariableName");
     final String format = checkConfig.getProperty("format");
     final Map<String, String> messages = checkConfig.getMessages();
--- a/src/it/java/com/google/checkstyle/test/chapter5naming/rule528typevariablenames/ClassTypeParameterNameTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter5naming/rule528typevariablenames/ClassTypeParameterNameTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
 
-public class ClassTypeParameterNameTest extends AbstractGoogleModuleTestSupport {
+final class ClassTypeParameterNameTest extends AbstractGoogleModuleTestSupport {
 
   private static final String MSG_KEY = "name.invalidPattern";
 
@@ -34,7 +34,7 @@ public class ClassTypeParameterNameTest extends AbstractGoogleModuleTestSupport
   }
 
   @Test
-  public void testClassDefault() throws Exception {
+  void classDefault() throws Exception {
     final Configuration configuration = getModuleConfig("ClassTypeParameterName");
     final String format = configuration.getProperty("format");
     final Map<String, String> messages = configuration.getMessages();
--- a/src/it/java/com/google/checkstyle/test/chapter5naming/rule528typevariablenames/InterfaceTypeParameterNameTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter5naming/rule528typevariablenames/InterfaceTypeParameterNameTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
 
-public class InterfaceTypeParameterNameTest extends AbstractGoogleModuleTestSupport {
+final class InterfaceTypeParameterNameTest extends AbstractGoogleModuleTestSupport {
 
   private static final String MSG_KEY = "name.invalidPattern";
 
@@ -34,7 +34,7 @@ public class InterfaceTypeParameterNameTest extends AbstractGoogleModuleTestSupp
   }
 
   @Test
-  public void testInterfaceDefault() throws Exception {
+  void interfaceDefault() throws Exception {
     final Configuration configuration = getModuleConfig("InterfaceTypeParameterName");
     final String format = configuration.getProperty("format");
     final Map<String, String> messages = configuration.getMessages();
--- a/src/it/java/com/google/checkstyle/test/chapter5naming/rule528typevariablenames/MethodTypeParameterNameTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter5naming/rule528typevariablenames/MethodTypeParameterNameTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
 
-public class MethodTypeParameterNameTest extends AbstractGoogleModuleTestSupport {
+final class MethodTypeParameterNameTest extends AbstractGoogleModuleTestSupport {
 
   private static final String MSG_KEY = "name.invalidPattern";
 
@@ -34,7 +34,7 @@ public class MethodTypeParameterNameTest extends AbstractGoogleModuleTestSupport
   }
 
   @Test
-  public void testMethodDefault() throws Exception {
+  void methodDefault() throws Exception {
     final Configuration checkConfig = getModuleConfig("MethodTypeParameterName");
     final String format = checkConfig.getProperty("format");
     final Map<String, String> messages = checkConfig.getMessages();
--- a/src/it/java/com/google/checkstyle/test/chapter5naming/rule528typevariablenames/RecordTypeParameterNameTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter5naming/rule528typevariablenames/RecordTypeParameterNameTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
 
-public class RecordTypeParameterNameTest extends AbstractGoogleModuleTestSupport {
+final class RecordTypeParameterNameTest extends AbstractGoogleModuleTestSupport {
 
   private static final String MSG_KEY = "name.invalidPattern";
 
@@ -34,7 +34,7 @@ public class RecordTypeParameterNameTest extends AbstractGoogleModuleTestSupport
   }
 
   @Test
-  public void testRecordDefault() throws Exception {
+  void recordDefault() throws Exception {
     final Configuration configuration = getModuleConfig("RecordTypeParameterName");
     final String format = configuration.getProperty("format");
     final Map<String, String> messages = configuration.getMessages();
--- a/src/it/java/com/google/checkstyle/test/chapter5naming/rule53camelcase/AbbreviationAsWordInNameTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter5naming/rule53camelcase/AbbreviationAsWordInNameTest.java
@@ -25,7 +25,7 @@ import com.puppycrawl.tools.checkstyle.checks.naming.AbbreviationAsWordInNameChe
 import java.io.IOException;
 import org.junit.jupiter.api.Test;
 
-public class AbbreviationAsWordInNameTest extends AbstractGoogleModuleTestSupport {
+final class AbbreviationAsWordInNameTest extends AbstractGoogleModuleTestSupport {
 
   private static final String MSG_KEY = "abbreviation.as.word";
   private final Class<AbbreviationAsWordInNameCheck> clazz = AbbreviationAsWordInNameCheck.class;
@@ -36,7 +36,7 @@ public class AbbreviationAsWordInNameTest extends AbstractGoogleModuleTestSuppor
   }
 
   @Test
-  public void testAbbreviationAsWordInName() throws Exception {
+  void abbreviationAsWordInName() throws Exception {
     final int maxCapitalCount = 1;
 
     final String[] expected = {
--- a/src/it/java/com/google/checkstyle/test/chapter6programpractice/rule62donotignoreexceptions/EmptyBlockTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter6programpractice/rule62donotignoreexceptions/EmptyBlockTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.blocks.EmptyBlockCheck;
 import org.junit.jupiter.api.Test;
 
-public class EmptyBlockTest extends AbstractGoogleModuleTestSupport {
+final class EmptyBlockTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class EmptyBlockTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testEmptyBlockCatch() throws Exception {
+  void emptyBlockCatch() throws Exception {
     final String[] expected = {
       "29:17: " + getCheckMessage(EmptyBlockCheck.class, "block.empty", "finally"),
       "50:21: " + getCheckMessage(EmptyBlockCheck.class, "block.empty", "finally"),
--- a/src/it/java/com/google/checkstyle/test/chapter6programpractice/rule64finalizers/NoFinalizerTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter6programpractice/rule64finalizers/NoFinalizerTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.coding.NoFinalizerCheck;
 import org.junit.jupiter.api.Test;
 
-public class NoFinalizerTest extends AbstractGoogleModuleTestSupport {
+final class NoFinalizerTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class NoFinalizerTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testNoFinalizerBasic() throws Exception {
+  void noFinalizerBasic() throws Exception {
     final String msg = getCheckMessage(NoFinalizerCheck.class, "avoid.finalizer.method");
 
     final String[] expected = {
@@ -47,7 +47,7 @@ public class NoFinalizerTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testNoFinalizerExtended() throws Exception {
+  void noFinalizerExtended() throws Exception {
     final String msg = getCheckMessage(NoFinalizerCheck.class, "avoid.finalizer.method");
 
     final String[] expected = {
--- a/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule711generalform/InvalidJavadocPositionTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule711generalform/InvalidJavadocPositionTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.javadoc.InvalidJavadocPositionCheck;
 import org.junit.jupiter.api.Test;
 
-public class InvalidJavadocPositionTest extends AbstractGoogleModuleTestSupport {
+final class InvalidJavadocPositionTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class InvalidJavadocPositionTest extends AbstractGoogleModuleTestSupport
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String message = getCheckMessage(InvalidJavadocPositionCheck.class, "invalid.position");
 
     final String[] expected = {
--- a/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule711generalform/SingleLineJavadocTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule711generalform/SingleLineJavadocTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.javadoc.SingleLineJavadocCheck;
 import org.junit.jupiter.api.Test;
 
-public class SingleLineJavadocTest extends AbstractGoogleModuleTestSupport {
+final class SingleLineJavadocTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class SingleLineJavadocTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testSingleLineJavadoc() throws Exception {
+  void singleLineJavadoc() throws Exception {
     final String msg = getCheckMessage(SingleLineJavadocCheck.class, "singleline.javadoc");
 
     final String[] expected = {
--- a/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule712paragraphs/JavadocParagraphTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule712paragraphs/JavadocParagraphTest.java
@@ -25,7 +25,7 @@ import com.puppycrawl.tools.checkstyle.checks.javadoc.JavadocParagraphCheck;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class JavadocParagraphTest extends AbstractGoogleModuleTestSupport {
+final class JavadocParagraphTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class JavadocParagraphTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testJavadocParagraphCorrect() throws Exception {
+  void javadocParagraphCorrect() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("JavadocParagraph");
@@ -44,7 +44,7 @@ public class JavadocParagraphTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testJavadocParagraphIncorrect() throws Exception {
+  void javadocParagraphIncorrect() throws Exception {
     final String msgBefore =
         getCheckMessage(JavadocParagraphCheck.class, "javadoc.paragraph.line.before");
     final String msgRed =
--- a/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule712paragraphs/RequireEmptyLineBeforeBlockTagGroupTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule712paragraphs/RequireEmptyLineBeforeBlockTagGroupTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.io.IOException;
 import org.junit.jupiter.api.Test;
 
-public class RequireEmptyLineBeforeBlockTagGroupTest extends AbstractGoogleModuleTestSupport {
+final class RequireEmptyLineBeforeBlockTagGroupTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class RequireEmptyLineBeforeBlockTagGroupTest extends AbstractGoogleModul
   }
 
   @Test
-  public void testJavadocParagraphCorrect() throws Exception {
+  void javadocParagraphCorrect() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("RequireEmptyLineBeforeBlockTagGroup");
@@ -45,7 +45,7 @@ public class RequireEmptyLineBeforeBlockTagGroupTest extends AbstractGoogleModul
   }
 
   @Test
-  public void testJavadocParagraphIncorrect() throws Exception {
+  void javadocParagraphIncorrect() throws Exception {
     final String[] expected = {
       "5: " + getTagCheckMessage("@since"),
       "11: " + getTagCheckMessage("@param"),
--- a/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule713atclauses/AtclauseOrderTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule713atclauses/AtclauseOrderTest.java
@@ -25,7 +25,7 @@ import com.puppycrawl.tools.checkstyle.checks.javadoc.AtclauseOrderCheck;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class AtclauseOrderTest extends AbstractGoogleModuleTestSupport {
+final class AtclauseOrderTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class AtclauseOrderTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testCorrect1() throws Exception {
+  void correct1() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("AtclauseOrder");
@@ -44,7 +44,7 @@ public class AtclauseOrderTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testCorrect2() throws Exception {
+  void correct2() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("AtclauseOrder");
@@ -55,7 +55,7 @@ public class AtclauseOrderTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testCorrect3() throws Exception {
+  void correct3() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("AtclauseOrder");
@@ -66,7 +66,7 @@ public class AtclauseOrderTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testIncorrect1() throws Exception {
+  void incorrect1() throws Exception {
     final String tagOrder = "[@param, @return, @throws, @deprecated]";
     final String msg = getCheckMessage(AtclauseOrderCheck.class, "at.clause.order", tagOrder);
 
@@ -90,7 +90,7 @@ public class AtclauseOrderTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testIncorrect2() throws Exception {
+  void incorrect2() throws Exception {
     final String tagOrder = "[@param, @return, @throws, @deprecated]";
     final String msg = getCheckMessage(AtclauseOrderCheck.class, "at.clause.order", tagOrder);
 
@@ -112,7 +112,7 @@ public class AtclauseOrderTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testIncorrect3() throws Exception {
+  void incorrect3() throws Exception {
     final String tagOrder = "[@param, @return, @throws, @deprecated]";
     final String msg = getCheckMessage(AtclauseOrderCheck.class, "at.clause.order", tagOrder);
 
--- a/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule713atclauses/JavadocTagContinuationIndentationTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule713atclauses/JavadocTagContinuationIndentationTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.javadoc.JavadocTagContinuationIndentationCheck;
 import org.junit.jupiter.api.Test;
 
-public class JavadocTagContinuationIndentationTest extends AbstractGoogleModuleTestSupport {
+final class JavadocTagContinuationIndentationTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class JavadocTagContinuationIndentationTest extends AbstractGoogleModuleT
   }
 
   @Test
-  public void testWithDefaultConfiguration() throws Exception {
+  void withDefaultConfiguration() throws Exception {
     final String msg =
         getCheckMessage(JavadocTagContinuationIndentationCheck.class, "tag.continuation.indent", 4);
 
--- a/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule713atclauses/NonEmptyAtclauseDescriptionTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule713atclauses/NonEmptyAtclauseDescriptionTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.javadoc.NonEmptyAtclauseDescriptionCheck;
 import org.junit.jupiter.api.Test;
 
-public class NonEmptyAtclauseDescriptionTest extends AbstractGoogleModuleTestSupport {
+final class NonEmptyAtclauseDescriptionTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class NonEmptyAtclauseDescriptionTest extends AbstractGoogleModuleTestSup
   }
 
   @Test
-  public void testDefaultConfiguration() throws Exception {
+  void defaultConfiguration() throws Exception {
     final String msg =
         getCheckMessage(NonEmptyAtclauseDescriptionCheck.class, "non.empty.atclause");
 
@@ -58,7 +58,7 @@ public class NonEmptyAtclauseDescriptionTest extends AbstractGoogleModuleTestSup
   }
 
   @Test
-  public void testSpaceSequence() throws Exception {
+  void spaceSequence() throws Exception {
     final String msg =
         getCheckMessage(NonEmptyAtclauseDescriptionCheck.class, "non.empty.atclause");
 
--- a/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule72thesummaryfragment/SummaryJavadocTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule72thesummaryfragment/SummaryJavadocTest.java
@@ -25,7 +25,7 @@ import com.puppycrawl.tools.checkstyle.checks.javadoc.SummaryJavadocCheck;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class SummaryJavadocTest extends AbstractGoogleModuleTestSupport {
+final class SummaryJavadocTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class SummaryJavadocTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testCorrect() throws Exception {
+  void correct() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     final Configuration checkConfig = getModuleConfig("SummaryJavadoc");
@@ -44,7 +44,7 @@ public class SummaryJavadocTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testIncorrect() throws Exception {
+  void incorrect() throws Exception {
     final String msgFirstSentence =
         getCheckMessage(SummaryJavadocCheck.class, "summary.first.sentence");
     final String msgForbiddenFragment =
--- a/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule731selfexplanatory/JavadocMethodTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule731selfexplanatory/JavadocMethodTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class JavadocMethodTest extends AbstractGoogleModuleTestSupport {
+final class JavadocMethodTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class JavadocMethodTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testJavadocMethod() throws Exception {
+  void javadocMethod() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
--- a/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule731selfexplanatory/MissingJavadocMethodTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule731selfexplanatory/MissingJavadocMethodTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.javadoc.MissingJavadocMethodCheck;
 import org.junit.jupiter.api.Test;
 
-public class MissingJavadocMethodTest extends AbstractGoogleModuleTestSupport {
+final class MissingJavadocMethodTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class MissingJavadocMethodTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testJavadocMethod() throws Exception {
+  void javadocMethod() throws Exception {
     final String msg = getCheckMessage(MissingJavadocMethodCheck.class, "javadoc.missing");
 
     final String[] expected = {
--- a/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule734nonrequiredjavadoc/InvalidJavadocPositionTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule734nonrequiredjavadoc/InvalidJavadocPositionTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.checks.javadoc.InvalidJavadocPositionCheck;
 import org.junit.jupiter.api.Test;
 
-public class InvalidJavadocPositionTest extends AbstractGoogleModuleTestSupport {
+final class InvalidJavadocPositionTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class InvalidJavadocPositionTest extends AbstractGoogleModuleTestSupport
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String message = getCheckMessage(InvalidJavadocPositionCheck.class, "invalid.position");
 
     final String[] expected = {
--- a/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule73wherejavadocrequired/MissingJavadocTypeTest.java
+++ b/src/it/java/com/google/checkstyle/test/chapter7javadoc/rule73wherejavadocrequired/MissingJavadocTypeTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.checks.javadoc.MissingJavadocTypeCheck;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class MissingJavadocTypeTest extends AbstractGoogleModuleTestSupport {
+final class MissingJavadocTypeTest extends AbstractGoogleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class MissingJavadocTypeTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testJavadocType() throws Exception {
+  void javadocType() throws Exception {
 
     final String[] expected = {
       "3:1: " + getCheckMessage(MissingJavadocTypeCheck.class, MSG_JAVADOC_MISSING),
@@ -58,7 +58,7 @@ public class MissingJavadocTypeTest extends AbstractGoogleModuleTestSupport {
   }
 
   @Test
-  public void testJavadocTypeNoViolations() throws Exception {
+  void javadocTypeNoViolations() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
--- a/src/it/java/com/sun/checkstyle/test/chapter5comments/rule52documentationcomments/InvalidJavadocPositionTest.java
+++ b/src/it/java/com/sun/checkstyle/test/chapter5comments/rule52documentationcomments/InvalidJavadocPositionTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.checks.javadoc.InvalidJavadocPositionChec
 import com.sun.checkstyle.test.base.AbstractSunModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class InvalidJavadocPositionTest extends AbstractSunModuleTestSupport {
+final class InvalidJavadocPositionTest extends AbstractSunModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class InvalidJavadocPositionTest extends AbstractSunModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String message = getCheckMessage(InvalidJavadocPositionCheck.class, "invalid.position");
 
     final String[] expected = {
--- a/src/it/java/com/sun/checkstyle/test/chapter6declarations/rule61numberperline/MultipleVariableDeclarationsTest.java
+++ b/src/it/java/com/sun/checkstyle/test/chapter6declarations/rule61numberperline/MultipleVariableDeclarationsTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.checks.coding.MultipleVariableDeclaration
 import com.sun.checkstyle.test.base.AbstractSunModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class MultipleVariableDeclarationsTest extends AbstractSunModuleTestSupport {
+final class MultipleVariableDeclarationsTest extends AbstractSunModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class MultipleVariableDeclarationsTest extends AbstractSunModuleTestSuppo
   }
 
   @Test
-  public void testMultipleVariableDeclarations() throws Exception {
+  void multipleVariableDeclarations() throws Exception {
     final String msgComma =
         getCheckMessage(
             MultipleVariableDeclarationsCheck.class, "multiple.variable.declarations.comma");
--- a/src/it/java/org/checkstyle/base/AbstractItModuleTestSupport.java
+++ b/src/it/java/org/checkstyle/base/AbstractItModuleTestSupport.java
@@ -20,6 +20,7 @@
 package org.checkstyle.base;
 
 import static com.google.common.truth.Truth.assertWithMessage;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.puppycrawl.tools.checkstyle.AbstractPathTestSupport;
 import com.puppycrawl.tools.checkstyle.Checker;
@@ -397,8 +398,7 @@ public abstract class AbstractItModuleTestSupport extends AbstractPathTestSuppor
 
     // process each of the lines
     try (ByteArrayInputStream inputStream = new ByteArrayInputStream(stream.toByteArray());
-        LineNumberReader lnr =
-            new LineNumberReader(new InputStreamReader(inputStream, StandardCharsets.UTF_8))) {
+        LineNumberReader lnr = new LineNumberReader(new InputStreamReader(inputStream, UTF_8))) {
       int previousLineNumber = 0;
       for (int index = 0; index < expected.length; index++) {
         final String expectedResult = messageFileName + ":" + expected[index];
@@ -493,7 +493,7 @@ public abstract class AbstractItModuleTestSupport extends AbstractPathTestSuppor
    */
   protected Integer[] getLinesWithWarn(String fileName) throws IOException {
     final List<Integer> result = new ArrayList<>();
-    try (BufferedReader br = Files.newBufferedReader(Paths.get(fileName), StandardCharsets.UTF_8)) {
+    try (BufferedReader br = Files.newBufferedReader(Paths.get(fileName), UTF_8)) {
       int lineNumber = 1;
       while (true) {
         final String line = br.readLine();
--- a/src/it/java/org/checkstyle/checks/imports/ImportOrderTest.java
+++ b/src/it/java/org/checkstyle/checks/imports/ImportOrderTest.java
@@ -25,7 +25,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.checkstyle.base.AbstractCheckstyleModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class ImportOrderTest extends AbstractCheckstyleModuleTestSupport {
+final class ImportOrderTest extends AbstractCheckstyleModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class ImportOrderTest extends AbstractCheckstyleModuleTestSupport {
   }
 
   @Test
-  public void testAndroid() throws Exception {
+  void android() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(ImportOrderCheck.class);
     checkConfig.addProperty(
         "groups", "android,androidx,com.android,dalvik,com,gov,junit,libcore,net,org,java,javax");
@@ -52,7 +52,7 @@ public class ImportOrderTest extends AbstractCheckstyleModuleTestSupport {
   }
 
   @Test
-  public void testSpotify() throws Exception {
+  void spotify() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(ImportOrderCheck.class);
     checkConfig.addProperty("groups", "android,com,net,junit,org,java,javax");
     checkConfig.addProperty("option", "bottom");
@@ -68,7 +68,7 @@ public class ImportOrderTest extends AbstractCheckstyleModuleTestSupport {
   }
 
   @Test
-  public void testTwitter() throws Exception {
+  void twitter() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(ImportOrderCheck.class);
     checkConfig.addProperty("caseSensitive", "true");
     checkConfig.addProperty("groups", "android,com.twitter,com,junit,net,org,java,javax");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/AbstractXpathTestSupport.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/AbstractXpathTestSupport.java
@@ -20,6 +20,7 @@
 package org.checkstyle.suppressionxpathfilter;
 
 import static com.google.common.truth.Truth.assertWithMessage;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.JavaParser;
@@ -114,7 +115,7 @@ public abstract class AbstractXpathTestSupport extends AbstractCheckstyleModuleT
   private String createSuppressionsXpathConfigFile(String checkName, List<String> xpathQueries)
       throws Exception {
     final Path suppressionsXpathConfigPath = Files.createTempFile(temporaryFolder, "", "");
-    try (Writer bw = Files.newBufferedWriter(suppressionsXpathConfigPath, StandardCharsets.UTF_8)) {
+    try (Writer bw = Files.newBufferedWriter(suppressionsXpathConfigPath, UTF_8)) {
       bw.write("<?xml version=\"1.0\"?>\n");
       bw.write("<!DOCTYPE suppressions PUBLIC\n");
       bw.write("    \"-//Checkstyle//DTD SuppressionXpathFilter ");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAbbreviationAsWordInNameTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAbbreviationAsWordInNameTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.naming.AbbreviationAsWordInNameCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionAbbreviationAsWordInNameTest extends AbstractXpathTestSupport {
+final class XpathRegressionAbbreviationAsWordInNameTest extends AbstractXpathTestSupport {
 
   private final String checkName = AbbreviationAsWordInNameCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionAbbreviationAsWordInNameTest extends AbstractXpathTe
   }
 
   @Test
-  public void testAnnotation() throws Exception {
+  void annotation() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAbbreviationAsWordInNameAnnotation.java"));
 
@@ -53,7 +53,7 @@ public class XpathRegressionAbbreviationAsWordInNameTest extends AbstractXpathTe
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT["
                 + "@text='SuppressionXpathRegressionAbbreviationAsWordInNameAnnotation']]"
                 + "/OBJBLOCK/ANNOTATION_DEF/IDENT[@text='ANNOTATION']");
@@ -62,7 +62,7 @@ public class XpathRegressionAbbreviationAsWordInNameTest extends AbstractXpathTe
   }
 
   @Test
-  public void testAnnotationField() throws Exception {
+  void annotationField() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAbbreviationAsWordInNameAnnotationField.java"));
 
@@ -79,7 +79,7 @@ public class XpathRegressionAbbreviationAsWordInNameTest extends AbstractXpathTe
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/ANNOTATION_DEF[./IDENT["
                 + "@text='SuppressionXpathRegressionAbbreviationAsWordInNameAnnotationField']]"
                 + "/OBJBLOCK/ANNOTATION_FIELD_DEF/IDENT[@text='ANNOTATION_FIELD']");
@@ -88,7 +88,7 @@ public class XpathRegressionAbbreviationAsWordInNameTest extends AbstractXpathTe
   }
 
   @Test
-  public void testClass() throws Exception {
+  void testClass() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAbbreviationAsWordInNameClass.java"));
 
@@ -105,7 +105,7 @@ public class XpathRegressionAbbreviationAsWordInNameTest extends AbstractXpathTe
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT["
                 + "@text='SuppressionXpathRegressionAbbreviationAsWordInNameClass']]"
                 + "/OBJBLOCK/CLASS_DEF/IDENT[@text='CLASS']");
@@ -114,7 +114,7 @@ public class XpathRegressionAbbreviationAsWordInNameTest extends AbstractXpathTe
   }
 
   @Test
-  public void testEnum() throws Exception {
+  void testEnum() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAbbreviationAsWordInNameEnum.java"));
 
@@ -131,7 +131,7 @@ public class XpathRegressionAbbreviationAsWordInNameTest extends AbstractXpathTe
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT["
                 + "@text='SuppressionXpathRegressionAbbreviationAsWordInNameEnum']]"
                 + "/OBJBLOCK/ENUM_DEF/IDENT[@text='ENUMERATION']");
@@ -140,7 +140,7 @@ public class XpathRegressionAbbreviationAsWordInNameTest extends AbstractXpathTe
   }
 
   @Test
-  public void testField() throws Exception {
+  void field() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAbbreviationAsWordInNameField.java"));
 
@@ -157,7 +157,7 @@ public class XpathRegressionAbbreviationAsWordInNameTest extends AbstractXpathTe
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT["
                 + "@text='SuppressionXpathRegressionAbbreviationAsWordInNameField']]"
                 + "/OBJBLOCK/VARIABLE_DEF/IDENT[@text='FIELD']");
@@ -166,7 +166,7 @@ public class XpathRegressionAbbreviationAsWordInNameTest extends AbstractXpathTe
   }
 
   @Test
-  public void testInterface() throws Exception {
+  void testInterface() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAbbreviationAsWordInNameInterface.java"));
 
@@ -183,7 +183,7 @@ public class XpathRegressionAbbreviationAsWordInNameTest extends AbstractXpathTe
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT["
                 + "@text='SuppressionXpathRegressionAbbreviationAsWordInNameInterface']]"
                 + "/OBJBLOCK/INTERFACE_DEF/IDENT[@text='INTERFACE']");
@@ -192,7 +192,7 @@ public class XpathRegressionAbbreviationAsWordInNameTest extends AbstractXpathTe
   }
 
   @Test
-  public void testMethod() throws Exception {
+  void method() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAbbreviationAsWordInNameMethod.java"));
 
@@ -209,7 +209,7 @@ public class XpathRegressionAbbreviationAsWordInNameTest extends AbstractXpathTe
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/INTERFACE_DEF[./IDENT["
                 + "@text='SuppressionXpathRegressionAbbreviationAsWordInNameMethod']]"
                 + "/OBJBLOCK/METHOD_DEF/IDENT[@text='METHOD']");
@@ -218,7 +218,7 @@ public class XpathRegressionAbbreviationAsWordInNameTest extends AbstractXpathTe
   }
 
   @Test
-  public void testParameter() throws Exception {
+  void parameter() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAbbreviationAsWordInNameParameter.java"));
 
@@ -235,7 +235,7 @@ public class XpathRegressionAbbreviationAsWordInNameTest extends AbstractXpathTe
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/INTERFACE_DEF[./IDENT["
                 + "@text='SuppressionXpathRegressionAbbreviationAsWordInNameParameter']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='method']]"
@@ -245,7 +245,7 @@ public class XpathRegressionAbbreviationAsWordInNameTest extends AbstractXpathTe
   }
 
   @Test
-  public void testVariable() throws Exception {
+  void variable() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAbbreviationAsWordInNameVariable.java"));
 
@@ -262,7 +262,7 @@ public class XpathRegressionAbbreviationAsWordInNameTest extends AbstractXpathTe
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT["
                 + "@text='SuppressionXpathRegressionAbbreviationAsWordInNameVariable']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='method']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAbstractClassNameTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAbstractClassNameTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionAbstractClassNameTest extends AbstractXpathTestSupport {
+final class XpathRegressionAbstractClassNameTest extends AbstractXpathTestSupport {
 
   private final String checkName = AbstractClassNameCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionAbstractClassNameTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testClassNameTop() throws Exception {
+  void classNameTop() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAbstractClassNameTop.java"));
 
@@ -66,7 +66,7 @@ public class XpathRegressionAbstractClassNameTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testClassNameInner() throws Exception {
+  void classNameInner() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAbstractClassNameInner.java"));
 
@@ -97,7 +97,7 @@ public class XpathRegressionAbstractClassNameTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testClassNameNoModifier() throws Exception {
+  void classNameNoModifier() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAbstractClassNameNoModifier.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAnnotationLocationTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAnnotationLocationTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionAnnotationLocationTest extends AbstractXpathTestSupport {
+final class XpathRegressionAnnotationLocationTest extends AbstractXpathTestSupport {
 
   private final String checkName = AnnotationLocationCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionAnnotationLocationTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testClass() throws Exception {
+  void testClass() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAnnotationLocationClass.java"));
 
@@ -68,7 +68,7 @@ public class XpathRegressionAnnotationLocationTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testInterface() throws Exception {
+  void testInterface() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAnnotationLocationInterface.java"));
 
@@ -101,7 +101,7 @@ public class XpathRegressionAnnotationLocationTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testEnum() throws Exception {
+  void testEnum() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAnnotationLocationEnum.java"));
 
@@ -133,7 +133,7 @@ public class XpathRegressionAnnotationLocationTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testMethod() throws Exception {
+  void method() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAnnotationLocationMethod.java"));
 
@@ -169,7 +169,7 @@ public class XpathRegressionAnnotationLocationTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testVariable() throws Exception {
+  void variable() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAnnotationLocationVariable.java"));
 
@@ -205,7 +205,7 @@ public class XpathRegressionAnnotationLocationTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testConstructor() throws Exception {
+  void constructor() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAnnotationLocationCTOR.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAnnotationOnSameLineTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAnnotationOnSameLineTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionAnnotationOnSameLineTest extends AbstractXpathTestSupport {
+final class XpathRegressionAnnotationOnSameLineTest extends AbstractXpathTestSupport {
 
   private final String checkName = AnnotationOnSameLineCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionAnnotationOnSameLineTest extends AbstractXpathTestSu
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAnnotationOnSameLineOne.java"));
 
@@ -78,7 +78,7 @@ public class XpathRegressionAnnotationOnSameLineTest extends AbstractXpathTestSu
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAnnotationOnSameLineTwo.java"));
 
@@ -113,7 +113,7 @@ public class XpathRegressionAnnotationOnSameLineTest extends AbstractXpathTestSu
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAnnotationOnSameLineThree.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAnnotationUseStyleTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAnnotationUseStyleTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.annotation.AnnotationUseStyleCheck;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionAnnotationUseStyleTest extends AbstractXpathTestSupport {
+final class XpathRegressionAnnotationUseStyleTest extends AbstractXpathTestSupport {
 
   private final String checkName = AnnotationUseStyleCheck.class.getSimpleName();
 
@@ -37,7 +37,7 @@ public class XpathRegressionAnnotationUseStyleTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAnnotationUseStyleOne.java"));
 
@@ -64,7 +64,7 @@ public class XpathRegressionAnnotationUseStyleTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAnnotationUseStyleTwo.java"));
 
@@ -99,7 +99,7 @@ public class XpathRegressionAnnotationUseStyleTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAnnotationUseStyleThree.java"));
 
@@ -136,7 +136,7 @@ public class XpathRegressionAnnotationUseStyleTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testFour() throws Exception {
+  void four() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAnnotationUseStyleFour.java"));
 
@@ -154,7 +154,7 @@ public class XpathRegressionAnnotationUseStyleTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionAnnotationUseStyleFour']]"
                 + "/MODIFIERS/ANNOTATION[./IDENT[@text='SuppressWarnings']]"
@@ -164,7 +164,7 @@ public class XpathRegressionAnnotationUseStyleTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testFive() throws Exception {
+  void five() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAnnotationUseStyleFive.java"));
 
@@ -200,7 +200,7 @@ public class XpathRegressionAnnotationUseStyleTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testSix() throws Exception {
+  void six() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAnnotationUseStyleSix.java"));
 
@@ -236,7 +236,7 @@ public class XpathRegressionAnnotationUseStyleTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testSeven() throws Exception {
+  void seven() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAnnotationUseStyleSeven.java"));
 
@@ -263,7 +263,7 @@ public class XpathRegressionAnnotationUseStyleTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testEight() throws Exception {
+  void eight() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAnnotationUseStyleEight.java"));
 
@@ -281,7 +281,7 @@ public class XpathRegressionAnnotationUseStyleTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionAnnotationUseStyleEight']]"
                 + "/MODIFIERS/ANNOTATION[./IDENT[@text='SuppressWarnings']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAnonInnerLengthTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAnonInnerLengthTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionAnonInnerLengthTest extends AbstractXpathTestSupport {
+final class XpathRegressionAnonInnerLengthTest extends AbstractXpathTestSupport {
 
   private final String checkName = AnonInnerLengthCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionAnonInnerLengthTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAnonInnerLengthDefault.java"));
 
@@ -63,7 +63,7 @@ public class XpathRegressionAnonInnerLengthTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testMaxLength() throws Exception {
+  void maxLength() throws Exception {
     final int maxLen = 5;
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionAnonInnerLength.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionArrayTrailingCommaTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionArrayTrailingCommaTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.ArrayTrailingCommaCheck;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionArrayTrailingCommaTest extends AbstractXpathTestSupport {
+final class XpathRegressionArrayTrailingCommaTest extends AbstractXpathTestSupport {
 
   private final String checkName = ArrayTrailingCommaCheck.class.getSimpleName();
 
@@ -37,7 +37,7 @@ public class XpathRegressionArrayTrailingCommaTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionArrayTrailingCommaOne.java"));
 
@@ -62,7 +62,7 @@ public class XpathRegressionArrayTrailingCommaTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionArrayTrailingCommaTwo.java"));
 
@@ -73,7 +73,7 @@ public class XpathRegressionArrayTrailingCommaTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionArrayTrailingCommaTwo']]"
                 + "/OBJBLOCK/VARIABLE_DEF[./IDENT[@text='d2']]/ASSIGN/EXPR/LITERAL_NEW"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionArrayTypeStyleTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionArrayTypeStyleTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.ArrayTypeStyleCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionArrayTypeStyleTest extends AbstractXpathTestSupport {
+final class XpathRegressionArrayTypeStyleTest extends AbstractXpathTestSupport {
 
   @Override
   protected String getCheckName() {
@@ -34,7 +34,7 @@ public class XpathRegressionArrayTypeStyleTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testVariable() throws Exception {
+  void variable() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionArrayTypeStyleVariable.java"));
 
@@ -45,7 +45,7 @@ public class XpathRegressionArrayTypeStyleTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionArrayTypeStyleVariable']]"
                 + "/OBJBLOCK/VARIABLE_DEF[./IDENT[@text='strings']]/TYPE["
@@ -55,7 +55,7 @@ public class XpathRegressionArrayTypeStyleTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testMethodDef() throws Exception {
+  void methodDef() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionArrayTypeStyleMethodDef.java"));
 
@@ -66,7 +66,7 @@ public class XpathRegressionArrayTypeStyleTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionArrayTypeStyleMethodDef']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='getData']]/TYPE/ARRAY_DECLARATOR");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAvoidDoubleBraceInitializationTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAvoidDoubleBraceInitializationTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionAvoidDoubleBraceInitializationTest extends AbstractXpathTestSupport {
+final class XpathRegressionAvoidDoubleBraceInitializationTest extends AbstractXpathTestSupport {
 
   private final Class<AvoidDoubleBraceInitializationCheck> clazz =
       AvoidDoubleBraceInitializationCheck.class;
@@ -37,7 +37,7 @@ public class XpathRegressionAvoidDoubleBraceInitializationTest extends AbstractX
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAvoidDoubleBraceInitialization.java"));
 
@@ -62,7 +62,7 @@ public class XpathRegressionAvoidDoubleBraceInitializationTest extends AbstractX
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAvoidDoubleBraceInitializationTwo.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAvoidEscapedUnicodeCharactersTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAvoidEscapedUnicodeCharactersTest.java
@@ -28,7 +28,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionAvoidEscapedUnicodeCharactersTest extends AbstractXpathTestSupport {
+final class XpathRegressionAvoidEscapedUnicodeCharactersTest extends AbstractXpathTestSupport {
   private final String checkName = AvoidEscapedUnicodeCharactersCheck.class.getSimpleName();
 
   @Override
@@ -37,7 +37,7 @@ public class XpathRegressionAvoidEscapedUnicodeCharactersTest extends AbstractXp
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAvoidEscapedUnicodeCharactersDefault.java"));
 
@@ -63,7 +63,7 @@ public class XpathRegressionAvoidEscapedUnicodeCharactersTest extends AbstractXp
   }
 
   @Test
-  public void testControlCharacters() throws Exception {
+  void controlCharacters() throws Exception {
     final File fileToProcess =
         new File(
             getPath(
@@ -94,7 +94,7 @@ public class XpathRegressionAvoidEscapedUnicodeCharactersTest extends AbstractXp
   }
 
   @Test
-  public void testTailComment() throws Exception {
+  void tailComment() throws Exception {
     final File fileToProcess =
         new File(
             getPath("SuppressionXpathRegressionAvoidEscapedUnicodeCharactersTailComment.java"));
@@ -124,7 +124,7 @@ public class XpathRegressionAvoidEscapedUnicodeCharactersTest extends AbstractXp
   }
 
   @Test
-  public void testAllCharactersEscaped() throws Exception {
+  void allCharactersEscaped() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAvoidEscapedUnicodeCharactersAllEscaped.java"));
 
@@ -153,7 +153,7 @@ public class XpathRegressionAvoidEscapedUnicodeCharactersTest extends AbstractXp
   }
 
   @Test
-  public void testNonPrintableCharacters() throws Exception {
+  void nonPrintableCharacters() throws Exception {
     final File fileToProcess =
         new File(
             getPath("SuppressionXpathRegressionAvoidEscapedUnicodeCharactersNonPrintable.java"));
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAvoidInlineConditionalsTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAvoidInlineConditionalsTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.AvoidInlineConditionalsCheck;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionAvoidInlineConditionalsTest extends AbstractXpathTestSupport {
+final class XpathRegressionAvoidInlineConditionalsTest extends AbstractXpathTestSupport {
 
   @Override
   protected String getCheckName() {
@@ -35,7 +35,7 @@ public class XpathRegressionAvoidInlineConditionalsTest extends AbstractXpathTes
   }
 
   @Test
-  public void testInlineConditionalsVariableDef() throws Exception {
+  void inlineConditionalsVariableDef() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAvoidInlineConditionalsVariableDef.java"));
 
@@ -63,7 +63,7 @@ public class XpathRegressionAvoidInlineConditionalsTest extends AbstractXpathTes
   }
 
   @Test
-  public void testInlineConditionalsAssign() throws Exception {
+  void inlineConditionalsAssign() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAvoidInlineConditionalsAssign.java"));
 
@@ -77,7 +77,7 @@ public class XpathRegressionAvoidInlineConditionalsTest extends AbstractXpathTes
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT[@text='"
                 + "SuppressionXpathRegressionAvoidInlineConditionalsAssign']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='setB']]/SLIST"
@@ -87,7 +87,7 @@ public class XpathRegressionAvoidInlineConditionalsTest extends AbstractXpathTes
   }
 
   @Test
-  public void testInlineConditionalsAssert() throws Exception {
+  void inlineConditionalsAssert() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAvoidInlineConditionalsAssert.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAvoidNestedBlocksTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAvoidNestedBlocksTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.blocks.AvoidNestedBlocksCheck;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionAvoidNestedBlocksTest extends AbstractXpathTestSupport {
+final class XpathRegressionAvoidNestedBlocksTest extends AbstractXpathTestSupport {
 
   @Override
   protected String getCheckName() {
@@ -35,7 +35,7 @@ public class XpathRegressionAvoidNestedBlocksTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testEmpty() throws Exception {
+  void empty() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAvoidNestedBlocksEmpty.java"));
 
@@ -48,7 +48,7 @@ public class XpathRegressionAvoidNestedBlocksTest extends AbstractXpathTestSuppo
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionAvoidNestedBlocksEmpty']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='empty']]/SLIST/SLIST");
@@ -57,7 +57,7 @@ public class XpathRegressionAvoidNestedBlocksTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testVariableAssignment() throws Exception {
+  void variableAssignment() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAvoidNestedBlocksVariable.java"));
 
@@ -70,7 +70,7 @@ public class XpathRegressionAvoidNestedBlocksTest extends AbstractXpathTestSuppo
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionAvoidNestedBlocksVariable']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='varAssign']]/SLIST/SLIST");
@@ -79,7 +79,7 @@ public class XpathRegressionAvoidNestedBlocksTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testSwitchAllowInSwitchCaseFalse() throws Exception {
+  void switchAllowInSwitchCaseFalse() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAvoidNestedBlocksSwitch1.java"));
 
@@ -112,7 +112,7 @@ public class XpathRegressionAvoidNestedBlocksTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testSwitchAllowInSwitchCaseTrue() throws Exception {
+  void switchAllowInSwitchCaseTrue() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAvoidNestedBlocksSwitch2.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAvoidNoArgumentSuperConstructorCallTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAvoidNoArgumentSuperConstructorCallTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.AvoidNoArgumentSuperConstructorCallCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionAvoidNoArgumentSuperConstructorCallTest
+final class XpathRegressionAvoidNoArgumentSuperConstructorCallTest
     extends AbstractXpathTestSupport {
 
   private static final Class<AvoidNoArgumentSuperConstructorCallCheck> CLASS =
@@ -38,7 +38,7 @@ public class XpathRegressionAvoidNoArgumentSuperConstructorCallTest
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAvoidNoArgumentSuperConstructorCall.java"));
 
@@ -49,7 +49,7 @@ public class XpathRegressionAvoidNoArgumentSuperConstructorCallTest
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionAvoidNoArgumentSuperConstructorCall']]"
                 + "/OBJBLOCK/CTOR_DEF[./IDENT["
@@ -60,7 +60,7 @@ public class XpathRegressionAvoidNoArgumentSuperConstructorCallTest
   }
 
   @Test
-  public void testInnerClass() throws Exception {
+  void innerClass() throws Exception {
     final File fileToProcess =
         new File(
             getPath(
@@ -73,7 +73,7 @@ public class XpathRegressionAvoidNoArgumentSuperConstructorCallTest
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT[@text="
                 + "'SuppressionXpathRegressionAvoidNoArgumentSuperConstructorCallInnerClass']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='test']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAvoidStarImportTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAvoidStarImportTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.imports.AvoidStarImportCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionAvoidStarImportTest extends AbstractXpathTestSupport {
+final class XpathRegressionAvoidStarImportTest extends AbstractXpathTestSupport {
 
   private static final Class<AvoidStarImportCheck> CLASS = AvoidStarImportCheck.class;
 
@@ -36,7 +36,7 @@ public class XpathRegressionAvoidStarImportTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionAvoidStarImport1.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(CLASS);
@@ -47,13 +47,13 @@ public class XpathRegressionAvoidStarImportTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList("/COMPILATION_UNIT/STATIC_IMPORT/DOT");
+        ImmutableList.of("/COMPILATION_UNIT/STATIC_IMPORT/DOT");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionAvoidStarImport2.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(CLASS);
@@ -62,8 +62,7 @@ public class XpathRegressionAvoidStarImportTest extends AbstractXpathTestSupport
       "4:15: " + getCheckMessage(CLASS, AvoidStarImportCheck.MSG_KEY, "java.io.*"),
     };
 
-    final List<String> expectedXpathQueries =
-        Collections.singletonList("/COMPILATION_UNIT/IMPORT/DOT");
+    final List<String> expectedXpathQueries = ImmutableList.of("/COMPILATION_UNIT/IMPORT/DOT");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAvoidStaticImportTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionAvoidStaticImportTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.imports.AvoidStaticImportCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionAvoidStaticImportTest extends AbstractXpathTestSupport {
+final class XpathRegressionAvoidStaticImportTest extends AbstractXpathTestSupport {
 
   private static final Class<AvoidStaticImportCheck> CLASS = AvoidStaticImportCheck.class;
 
@@ -36,7 +36,7 @@ public class XpathRegressionAvoidStaticImportTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAvoidStaticImport1.java"));
 
@@ -48,13 +48,13 @@ public class XpathRegressionAvoidStaticImportTest extends AbstractXpathTestSuppo
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList("/COMPILATION_UNIT/STATIC_IMPORT/DOT");
+        ImmutableList.of("/COMPILATION_UNIT/STATIC_IMPORT/DOT");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionAvoidStaticImport2.java"));
 
@@ -66,8 +66,7 @@ public class XpathRegressionAvoidStaticImportTest extends AbstractXpathTestSuppo
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
-            "/COMPILATION_UNIT/STATIC_IMPORT/DOT[./IDENT[@text='createTempFile']]");
+        ImmutableList.of("/COMPILATION_UNIT/STATIC_IMPORT/DOT[./IDENT[@text='createTempFile']]");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionBooleanExpressionComplexityTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionBooleanExpressionComplexityTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.metrics.BooleanExpressionComplexityCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionBooleanExpressionComplexityTest extends AbstractXpathTestSupport {
+final class XpathRegressionBooleanExpressionComplexityTest extends AbstractXpathTestSupport {
 
   @Override
   protected String getCheckName() {
@@ -34,7 +34,7 @@ public class XpathRegressionBooleanExpressionComplexityTest extends AbstractXpat
   }
 
   @Test
-  public void testMethodOne() throws Exception {
+  void methodOne() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionBooleanExpressionComplexityOne.java"));
 
@@ -51,7 +51,7 @@ public class XpathRegressionBooleanExpressionComplexityTest extends AbstractXpat
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionBooleanExpressionComplexityOne']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='methodOne']]/SLIST"
@@ -62,7 +62,7 @@ public class XpathRegressionBooleanExpressionComplexityTest extends AbstractXpat
   }
 
   @Test
-  public void testMethodTwo() throws Exception {
+  void methodTwo() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionBooleanExpressionComplexityTwo.java"));
 
@@ -79,7 +79,7 @@ public class XpathRegressionBooleanExpressionComplexityTest extends AbstractXpat
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT["
                 + "@text='SuppressionXpathRegressionBooleanExpressionComplexityTwo']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='methodTwo']]/SLIST/VARIABLE_DEF"
@@ -89,7 +89,7 @@ public class XpathRegressionBooleanExpressionComplexityTest extends AbstractXpat
   }
 
   @Test
-  public void testMethodThree() throws Exception {
+  void methodThree() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionBoolean" + "ExpressionComplexityThree.java"));
 
@@ -106,7 +106,7 @@ public class XpathRegressionBooleanExpressionComplexityTest extends AbstractXpat
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT["
                 + "@text='SuppressionXpathRegressionBooleanExpressionComplexityThree']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='methodThree']]/SLIST/LITERAL_IF");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionCatchParameterNameTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionCatchParameterNameTest.java
@@ -21,14 +21,14 @@ package org.checkstyle.suppressionxpathfilter;
 
 import static com.puppycrawl.tools.checkstyle.checks.naming.AbstractNameCheck.MSG_INVALID_PATTERN;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.naming.CatchParameterNameCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionCatchParameterNameTest extends AbstractXpathTestSupport {
+final class XpathRegressionCatchParameterNameTest extends AbstractXpathTestSupport {
   private final String checkName = CatchParameterNameCheck.class.getSimpleName();
 
   @Override
@@ -37,7 +37,7 @@ public class XpathRegressionCatchParameterNameTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testSimple() throws Exception {
+  void simple() throws Exception {
     final String pattern = "^(e|t|ex|[a-z][a-z][a-zA-Z]+)$";
 
     final DefaultConfiguration moduleConfig = createModuleConfig(CatchParameterNameCheck.class);
@@ -50,7 +50,7 @@ public class XpathRegressionCatchParameterNameTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionCatchParameterNameSimple']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='method']]"
@@ -60,7 +60,7 @@ public class XpathRegressionCatchParameterNameTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testNested() throws Exception {
+  void nested() throws Exception {
     final String pattern = "^(e|t|ex|[a-z][a-z][a-zA-Z]+)$";
 
     final DefaultConfiguration moduleConfig = createModuleConfig(CatchParameterNameCheck.class);
@@ -73,7 +73,7 @@ public class XpathRegressionCatchParameterNameTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionCatchParameterNameNested']]"
                 + "/OBJBLOCK/CLASS_DEF[./IDENT[@text='NestedClass']]"
@@ -85,7 +85,7 @@ public class XpathRegressionCatchParameterNameTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testStaticInit() throws Exception {
+  void staticInit() throws Exception {
     final String pattern = "^[a-z][a-zA-Z0-9]+$";
 
     final DefaultConfiguration moduleConfig = createModuleConfig(CatchParameterNameCheck.class);
@@ -99,7 +99,7 @@ public class XpathRegressionCatchParameterNameTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionCatchParameterNameStaticInit']]"
                 + "/OBJBLOCK/STATIC_INIT/SLIST"
@@ -109,7 +109,7 @@ public class XpathRegressionCatchParameterNameTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testAnonymous() throws Exception {
+  void anonymous() throws Exception {
     final String pattern = "^[a-z][a-zA-Z0-9]+$";
 
     final DefaultConfiguration moduleConfig = createModuleConfig(CatchParameterNameCheck.class);
@@ -124,7 +124,7 @@ public class XpathRegressionCatchParameterNameTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionCatchParameterNameAnonymous']]"
                 + "/OBJBLOCK/CLASS_DEF[./IDENT[@text='InnerClass']]"
@@ -137,7 +137,7 @@ public class XpathRegressionCatchParameterNameTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testLambda() throws Exception {
+  void lambda() throws Exception {
     final String pattern = "^[A-Z][a-z]+$";
 
     final DefaultConfiguration moduleConfig = createModuleConfig(CatchParameterNameCheck.class);
@@ -151,7 +151,7 @@ public class XpathRegressionCatchParameterNameTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionCatchParameterNameLambda']]"
                 + "/OBJBLOCK/VARIABLE_DEF[./IDENT[@text='lambdaFunction']]"
@@ -163,7 +163,7 @@ public class XpathRegressionCatchParameterNameTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testEnum() throws Exception {
+  void testEnum() throws Exception {
     final String pattern = "^[A-Z][a-z]+$";
 
     final DefaultConfiguration moduleConfig = createModuleConfig(CatchParameterNameCheck.class);
@@ -178,7 +178,7 @@ public class XpathRegressionCatchParameterNameTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/ENUM_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionCatchParameterNameEnum']]"
                 + "/OBJBLOCK/ENUM_CONSTANT_DEF[./IDENT[@text='VALUE']]"
@@ -190,7 +190,7 @@ public class XpathRegressionCatchParameterNameTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testInterface() throws Exception {
+  void testInterface() throws Exception {
     final String pattern = "^[A-Z][a-z]+$";
 
     final DefaultConfiguration moduleConfig = createModuleConfig(CatchParameterNameCheck.class);
@@ -204,7 +204,7 @@ public class XpathRegressionCatchParameterNameTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/INTERFACE_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionCatchParameterNameInterface']]"
                 + "/OBJBLOCK/INTERFACE_DEF[./IDENT[@text='InnerInterface']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionClassMemberImpliedModifierTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionClassMemberImpliedModifierTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionClassMemberImpliedModifierTest extends AbstractXpathTestSupport {
+final class XpathRegressionClassMemberImpliedModifierTest extends AbstractXpathTestSupport {
 
   private final String checkName = ClassMemberImpliedModifierCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionClassMemberImpliedModifierTest extends AbstractXpath
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionClassMemberImpliedModifierOne.java"));
 
@@ -68,7 +68,7 @@ public class XpathRegressionClassMemberImpliedModifierTest extends AbstractXpath
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionClassMemberImpliedModifierTwo.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionCommentsIndentationTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionCommentsIndentationTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.indentation.CommentsIndentationCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionCommentsIndentationTest extends AbstractXpathTestSupport {
+final class XpathRegressionCommentsIndentationTest extends AbstractXpathTestSupport {
 
   private final String checkName = CommentsIndentationCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionCommentsIndentationTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testSingleLine() throws Exception {
+  void singleLine() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionCommentsIndentation" + "SingleLine.java"));
 
@@ -48,7 +48,7 @@ public class XpathRegressionCommentsIndentationTest extends AbstractXpathTestSup
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionCommentsIndentationSingleLine']]"
                 + "/OBJBLOCK/SINGLE_LINE_COMMENT[./COMMENT_CONTENT[@text=' Comment // warn\\n']]");
@@ -57,7 +57,7 @@ public class XpathRegressionCommentsIndentationTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testBlock() throws Exception {
+  void block() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionCommentsIndentation" + "Block.java"));
 
@@ -69,7 +69,7 @@ public class XpathRegressionCommentsIndentationTest extends AbstractXpathTestSup
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionCommentsIndentationBlock']]/OBJBLOCK/"
                 + "VARIABLE_DEF[./IDENT[@text='f']]/TYPE/BLOCK_COMMENT_BEGIN[./COMMENT_CONTENT"
@@ -79,7 +79,7 @@ public class XpathRegressionCommentsIndentationTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testSeparator() throws Exception {
+  void separator() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionCommentsIndentation" + "Separator.java"));
 
@@ -92,7 +92,7 @@ public class XpathRegressionCommentsIndentationTest extends AbstractXpathTestSup
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionCommentsIndentationSeparator']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='foo']]/MODIFIERS/SINGLE_LINE_COMMENT"
@@ -102,7 +102,7 @@ public class XpathRegressionCommentsIndentationTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testDistributedStatement() throws Exception {
+  void distributedStatement() throws Exception {
     final File fileToProcess =
         new File(
             getPath("SuppressionXpathRegressionCommentsIndentation" + "DistributedStatement.java"));
@@ -116,7 +116,7 @@ public class XpathRegressionCommentsIndentationTest extends AbstractXpathTestSup
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionCommentsIndentationDistributedStatement']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='foo']]/SLIST/SINGLE_LINE_COMMENT"
@@ -126,7 +126,7 @@ public class XpathRegressionCommentsIndentationTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testSingleLineBlock() throws Exception {
+  void singleLineBlock() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionCommentsIndentation" + "SingleLineBlock.java"));
 
@@ -138,7 +138,7 @@ public class XpathRegressionCommentsIndentationTest extends AbstractXpathTestSup
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionCommentsIndentationSingleLineBlock']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='foo']]/SLIST/SINGLE_LINE_COMMENT"
@@ -148,7 +148,7 @@ public class XpathRegressionCommentsIndentationTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testNonEmptyCase() throws Exception {
+  void nonEmptyCase() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionCommentsIndentation" + "NonEmptyCase.java"));
 
@@ -161,7 +161,7 @@ public class XpathRegressionCommentsIndentationTest extends AbstractXpathTestSup
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionCommentsIndentationNonEmptyCase']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='foo']]/SLIST/LITERAL_SWITCH/"
@@ -171,7 +171,7 @@ public class XpathRegressionCommentsIndentationTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testEmptyCase() throws Exception {
+  void emptyCase() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionCommentsIndentation" + "EmptyCase.java"));
 
@@ -184,7 +184,7 @@ public class XpathRegressionCommentsIndentationTest extends AbstractXpathTestSup
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionCommentsIndentationEmptyCase']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='foo']]/SLIST/LITERAL_SWITCH/"
@@ -194,7 +194,7 @@ public class XpathRegressionCommentsIndentationTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testWithinBlockStatement() throws Exception {
+  void withinBlockStatement() throws Exception {
     final File fileToProcess =
         new File(
             getPath("SuppressionXpathRegressionCommentsIndentation" + "WithinBlockStatement.java"));
@@ -208,7 +208,7 @@ public class XpathRegressionCommentsIndentationTest extends AbstractXpathTestSup
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionCommentsIndentationWithinBlockStatement']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='foo']]/SLIST/VARIABLE_DEF"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionConstantNameTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionConstantNameTest.java
@@ -21,14 +21,14 @@ package org.checkstyle.suppressionxpathfilter;
 
 import static com.puppycrawl.tools.checkstyle.checks.naming.AbstractNameCheck.MSG_INVALID_PATTERN;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.naming.ConstantNameCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionConstantNameTest extends AbstractXpathTestSupport {
+final class XpathRegressionConstantNameTest extends AbstractXpathTestSupport {
 
   private static final Class<ConstantNameCheck> CLASS = ConstantNameCheck.class;
   private static final String PATTERN = "^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$";
@@ -40,7 +40,7 @@ public class XpathRegressionConstantNameTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testLowercase() throws Exception {
+  void lowercase() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionConstantNameLowercase.java"));
 
@@ -51,7 +51,7 @@ public class XpathRegressionConstantNameTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionConstantNameLowercase']]"
                 + "/OBJBLOCK/VARIABLE_DEF/IDENT[@text='number']");
@@ -60,7 +60,7 @@ public class XpathRegressionConstantNameTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testCamelCase() throws Exception {
+  void camelCase() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionConstantNameCamelCase.java"));
 
@@ -71,7 +71,7 @@ public class XpathRegressionConstantNameTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionConstantNameCamelCase']]"
                 + "/OBJBLOCK/VARIABLE_DEF/IDENT[@text='badConstant']");
@@ -80,7 +80,7 @@ public class XpathRegressionConstantNameTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testWithBeginningUnderscore() throws Exception {
+  void withBeginningUnderscore() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionConstantNameWithBeginningUnderscore.java"));
 
@@ -91,7 +91,7 @@ public class XpathRegressionConstantNameTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionConstantNameWithBeginningUnderscore']]"
                 + "/OBJBLOCK/VARIABLE_DEF/IDENT[@text='_CONSTANT']");
@@ -100,7 +100,7 @@ public class XpathRegressionConstantNameTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testWithTwoUnderscores() throws Exception {
+  void withTwoUnderscores() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionConstantNameWithTwoUnderscores.java"));
 
@@ -111,7 +111,7 @@ public class XpathRegressionConstantNameTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionConstantNameWithTwoUnderscores']]"
                 + "/OBJBLOCK/VARIABLE_DEF/IDENT[@text='BAD__NAME']");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionCovariantEqualsTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionCovariantEqualsTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.CovariantEqualsCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionCovariantEqualsTest extends AbstractXpathTestSupport {
+final class XpathRegressionCovariantEqualsTest extends AbstractXpathTestSupport {
 
   private final String checkName = CovariantEqualsCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionCovariantEqualsTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testCovariantEqualsInClass() throws Exception {
+  void covariantEqualsInClass() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionCovariantEqualsInClass.java"));
 
@@ -47,7 +47,7 @@ public class XpathRegressionCovariantEqualsTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionCovariantEqualsInClass']]"
                 + "/OBJBLOCK/METHOD_DEF/IDENT[@text='equals']");
@@ -56,7 +56,7 @@ public class XpathRegressionCovariantEqualsTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testCovariantEqualsInEnum() throws Exception {
+  void covariantEqualsInEnum() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionCovariantEqualsInEnum.java"));
 
@@ -67,7 +67,7 @@ public class XpathRegressionCovariantEqualsTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/ENUM_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionCovariantEqualsInEnum']]"
                 + "/OBJBLOCK/METHOD_DEF/IDENT[@text='equals']");
@@ -76,7 +76,7 @@ public class XpathRegressionCovariantEqualsTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testCovariantEqualsInRecord() throws Exception {
+  void covariantEqualsInRecord() throws Exception {
     final File fileToProcess =
         new File(getNonCompilablePath("SuppressionXpathRegressionCovariantEqualsInRecord.java"));
 
@@ -87,7 +87,7 @@ public class XpathRegressionCovariantEqualsTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/RECORD_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionCovariantEqualsInRecord']]"
                 + "/OBJBLOCK/METHOD_DEF/IDENT[@text='equals']");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionCustomImportOrderTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionCustomImportOrderTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.imports.CustomImportOrderCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionCustomImportOrderTest extends AbstractXpathTestSupport {
+final class XpathRegressionCustomImportOrderTest extends AbstractXpathTestSupport {
 
   private final String checkName = CustomImportOrderCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionCustomImportOrderTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionCustomImportOrderOne.java"));
 
@@ -54,13 +54,13 @@ public class XpathRegressionCustomImportOrderTest extends AbstractXpathTestSuppo
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList("/COMPILATION_UNIT/STATIC_IMPORT[./DOT/IDENT[@text='PI']]");
+        ImmutableList.of("/COMPILATION_UNIT/STATIC_IMPORT[./DOT/IDENT[@text='PI']]");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionCustomImportOrderTwo.java"));
 
@@ -76,13 +76,13 @@ public class XpathRegressionCustomImportOrderTest extends AbstractXpathTestSuppo
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList("/COMPILATION_UNIT/IMPORT[./DOT/IDENT[@text='File']]");
+        ImmutableList.of("/COMPILATION_UNIT/IMPORT[./DOT/IDENT[@text='File']]");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionCustomImportOrderThree.java"));
 
@@ -98,13 +98,13 @@ public class XpathRegressionCustomImportOrderTest extends AbstractXpathTestSuppo
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList("/COMPILATION_UNIT/STATIC_IMPORT[./DOT/IDENT[@text='PI']]");
+        ImmutableList.of("/COMPILATION_UNIT/STATIC_IMPORT[./DOT/IDENT[@text='PI']]");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
 
   @Test
-  public void testFour() throws Exception {
+  void four() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionCustomImportOrderFour.java"));
 
@@ -120,13 +120,13 @@ public class XpathRegressionCustomImportOrderTest extends AbstractXpathTestSuppo
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList("/COMPILATION_UNIT/IMPORT[./DOT/IDENT[@text='DetailAST']]");
+        ImmutableList.of("/COMPILATION_UNIT/IMPORT[./DOT/IDENT[@text='DetailAST']]");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
 
   @Test
-  public void testFive() throws Exception {
+  void five() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionCustomImportOrderFive.java"));
 
@@ -143,13 +143,13 @@ public class XpathRegressionCustomImportOrderTest extends AbstractXpathTestSuppo
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList("/COMPILATION_UNIT/STATIC_IMPORT[./DOT/IDENT[@text='PI']]");
+        ImmutableList.of("/COMPILATION_UNIT/STATIC_IMPORT[./DOT/IDENT[@text='PI']]");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
 
   @Test
-  public void testSix() throws Exception {
+  void six() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionCustomImportOrderSix.java"));
 
@@ -168,7 +168,7 @@ public class XpathRegressionCustomImportOrderTest extends AbstractXpathTestSuppo
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList("/COMPILATION_UNIT/IMPORT[./DOT/IDENT[@text='DetailAST']]");
+        ImmutableList.of("/COMPILATION_UNIT/IMPORT[./DOT/IDENT[@text='DetailAST']]");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionCyclomaticComplexityTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionCyclomaticComplexityTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionCyclomaticComplexityTest extends AbstractXpathTestSupport {
+final class XpathRegressionCyclomaticComplexityTest extends AbstractXpathTestSupport {
 
   private final String checkName = CyclomaticComplexityCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionCyclomaticComplexityTest extends AbstractXpathTestSu
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
 
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionCyclomaticComplexityOne.java"));
@@ -66,7 +66,7 @@ public class XpathRegressionCyclomaticComplexityTest extends AbstractXpathTestSu
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionCyclomaticComplexityTwo.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionDeclarationOrderTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionDeclarationOrderTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionDeclarationOrderTest extends AbstractXpathTestSupport {
+final class XpathRegressionDeclarationOrderTest extends AbstractXpathTestSupport {
 
   private final String checkName = DeclarationOrderCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionDeclarationOrderTest extends AbstractXpathTestSuppor
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionDeclarationOrderOne.java"));
 
@@ -62,7 +62,7 @@ public class XpathRegressionDeclarationOrderTest extends AbstractXpathTestSuppor
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionDeclarationOrderTwo.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionDefaultComesLastTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionDefaultComesLastTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.DefaultComesLastCheck;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionDefaultComesLastTest extends AbstractXpathTestSupport {
+final class XpathRegressionDefaultComesLastTest extends AbstractXpathTestSupport {
 
   private final String checkName = DefaultComesLastCheck.class.getSimpleName();
 
@@ -37,7 +37,7 @@ public class XpathRegressionDefaultComesLastTest extends AbstractXpathTestSuppor
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionDefaultComesLastOne.java"));
 
@@ -62,7 +62,7 @@ public class XpathRegressionDefaultComesLastTest extends AbstractXpathTestSuppor
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionDefaultComesLastTwo.java"));
 
@@ -77,7 +77,7 @@ public class XpathRegressionDefaultComesLastTest extends AbstractXpathTestSuppor
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionDefaultComesLastTwo']]/OBJBLOCK"
                 + "/METHOD_DEF[./IDENT[@text='test']]/SLIST/LITERAL_SWITCH/CASE_GROUP"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionEmptyBlockTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionEmptyBlockTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.blocks.EmptyBlockCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionEmptyBlockTest extends AbstractXpathTestSupport {
+final class XpathRegressionEmptyBlockTest extends AbstractXpathTestSupport {
   private final String checkName = EmptyBlockCheck.class.getSimpleName();
 
   @Override
@@ -35,7 +35,7 @@ public class XpathRegressionEmptyBlockTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testEmptyForLoopEmptyBlock() throws Exception {
+  void emptyForLoopEmptyBlock() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionEmptyBlockEmpty.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(EmptyBlockCheck.class);
     moduleConfig.addProperty("option", "TEXT");
@@ -43,7 +43,7 @@ public class XpathRegressionEmptyBlockTest extends AbstractXpathTestSupport {
       "5:38: " + getCheckMessage(EmptyBlockCheck.class, EmptyBlockCheck.MSG_KEY_BLOCK_EMPTY, "for"),
     };
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text='SuppressionXpathRegressionEmptyBlockEmpty']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='emptyLoop']]"
@@ -52,14 +52,14 @@ public class XpathRegressionEmptyBlockTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testEmptyForLoopEmptyStatement() throws Exception {
+  void emptyForLoopEmptyStatement() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionEmptyBlockEmpty.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(EmptyBlockCheck.class);
     final String[] expectedViolation = {
       "5:38: " + getCheckMessage(EmptyBlockCheck.class, EmptyBlockCheck.MSG_KEY_BLOCK_NO_STATEMENT),
     };
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text='SuppressionXpathRegressionEmptyBlockEmpty']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='emptyLoop']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionEmptyCatchBlockTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionEmptyCatchBlockTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.blocks.EmptyCatchBlockCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionEmptyCatchBlockTest extends AbstractXpathTestSupport {
+final class XpathRegressionEmptyCatchBlockTest extends AbstractXpathTestSupport {
 
   private final Class<EmptyCatchBlockCheck> clazz = EmptyCatchBlockCheck.class;
 
@@ -36,7 +36,7 @@ public class XpathRegressionEmptyCatchBlockTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionEmptyCatchBlock1.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(clazz);
@@ -46,7 +46,7 @@ public class XpathRegressionEmptyCatchBlockTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionEmptyCatchBlock1']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='main']]"
@@ -56,7 +56,7 @@ public class XpathRegressionEmptyCatchBlockTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionEmptyCatchBlock2.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(clazz);
@@ -66,7 +66,7 @@ public class XpathRegressionEmptyCatchBlockTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionEmptyCatchBlock2']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='main']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionEmptyForInitializerPadTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionEmptyForInitializerPadTest.java
@@ -27,7 +27,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionEmptyForInitializerPadTest extends AbstractXpathTestSupport {
+final class XpathRegressionEmptyForInitializerPadTest extends AbstractXpathTestSupport {
 
   private final String checkName = EmptyForInitializerPadCheck.class.getSimpleName();
 
@@ -37,7 +37,7 @@ public class XpathRegressionEmptyForInitializerPadTest extends AbstractXpathTest
   }
 
   @Test
-  public void testPreceded() throws Exception {
+  void preceded() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionEmptyForInitializerPadPreceded.java"));
 
@@ -62,7 +62,7 @@ public class XpathRegressionEmptyForInitializerPadTest extends AbstractXpathTest
   }
 
   @Test
-  public void testNotPreceded() throws Exception {
+  void notPreceded() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionEmptyForInitializerPadNotPreceded.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionEmptyForIteratorPadTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionEmptyForIteratorPadTest.java
@@ -27,7 +27,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionEmptyForIteratorPadTest extends AbstractXpathTestSupport {
+final class XpathRegressionEmptyForIteratorPadTest extends AbstractXpathTestSupport {
 
   private final String checkName = EmptyForIteratorPadCheck.class.getSimpleName();
 
@@ -37,7 +37,7 @@ public class XpathRegressionEmptyForIteratorPadTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testFollowed() throws Exception {
+  void followed() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionEmptyForIteratorPadFollowed.java"));
 
@@ -62,7 +62,7 @@ public class XpathRegressionEmptyForIteratorPadTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testNotFollowed() throws Exception {
+  void notFollowed() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionEmptyForIteratorPadNotFollowed.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionEmptyLineSeparatorTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionEmptyLineSeparatorTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.EmptyLineSeparatorCheck;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionEmptyLineSeparatorTest extends AbstractXpathTestSupport {
+final class XpathRegressionEmptyLineSeparatorTest extends AbstractXpathTestSupport {
 
   @Override
   protected String getCheckName() {
@@ -35,7 +35,7 @@ public class XpathRegressionEmptyLineSeparatorTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionEmptyLineSeparator1.java"));
 
@@ -57,7 +57,7 @@ public class XpathRegressionEmptyLineSeparatorTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionEmptyLineSeparator2.java"));
 
@@ -77,7 +77,7 @@ public class XpathRegressionEmptyLineSeparatorTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionEmptyLineSeparator3.java"));
 
@@ -110,7 +110,7 @@ public class XpathRegressionEmptyLineSeparatorTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testFour() throws Exception {
+  void four() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionEmptyLineSeparator4.java"));
 
@@ -124,7 +124,7 @@ public class XpathRegressionEmptyLineSeparatorTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionEmptyLineSeparator4']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='foo1']]/SLIST/RCURLY");
@@ -133,7 +133,7 @@ public class XpathRegressionEmptyLineSeparatorTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testFive() throws Exception {
+  void five() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionEmptyLineSeparator5.java"));
 
@@ -148,7 +148,7 @@ public class XpathRegressionEmptyLineSeparatorTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionEmptyLineSeparator5']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='foo1']]/SLIST/LITERAL_TRY/SLIST"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionEmptyStatementTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionEmptyStatementTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.EmptyStatementCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionEmptyStatementTest extends AbstractXpathTestSupport {
+final class XpathRegressionEmptyStatementTest extends AbstractXpathTestSupport {
 
   private final String checkName = EmptyStatementCheck.class.getSimpleName();
 
@@ -36,14 +36,14 @@ public class XpathRegressionEmptyStatementTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testForLoopEmptyStatement() throws Exception {
+  void forLoopEmptyStatement() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionEmptyStatement1.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(EmptyStatementCheck.class);
     final String[] expectedViolation = {
       "5:36: " + getCheckMessage(EmptyStatementCheck.class, EmptyStatementCheck.MSG_KEY),
     };
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text='SuppressionXpathRegressionEmptyStatement1']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='foo']]"
@@ -52,14 +52,14 @@ public class XpathRegressionEmptyStatementTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testIfBlockEmptyStatement() throws Exception {
+  void ifBlockEmptyStatement() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionEmptyStatement2.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(EmptyStatementCheck.class);
     final String[] expectedViolation = {
       "6:19: " + getCheckMessage(EmptyStatementCheck.class, EmptyStatementCheck.MSG_KEY),
     };
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text='SuppressionXpathRegressionEmptyStatement2']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='foo']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionEqualsAvoidNullTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionEqualsAvoidNullTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionEqualsAvoidNullTest extends AbstractXpathTestSupport {
+final class XpathRegressionEqualsAvoidNullTest extends AbstractXpathTestSupport {
 
   private final Class<EqualsAvoidNullCheck> clazz = EqualsAvoidNullCheck.class;
 
@@ -36,7 +36,7 @@ public class XpathRegressionEqualsAvoidNullTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testEquals() throws Exception {
+  void testEquals() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionEqualsAvoidNull.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(clazz);
@@ -58,7 +58,7 @@ public class XpathRegressionEqualsAvoidNullTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testEqualsIgnoreCase() throws Exception {
+  void equalsIgnoreCase() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionEqualsAvoidNullIgnoreCase.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionEqualsHashCodeTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionEqualsHashCodeTest.java
@@ -26,14 +26,14 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionEqualsHashCodeTest extends AbstractXpathTestSupport {
+final class XpathRegressionEqualsHashCodeTest extends AbstractXpathTestSupport {
   @Override
   protected String getCheckName() {
     return EqualsHashCodeCheck.class.getSimpleName();
   }
 
   @Test
-  public void testEqualsOnly() throws Exception {
+  void equalsOnly() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionEqualsHashCode1.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(EqualsHashCodeCheck.class);
@@ -58,7 +58,7 @@ public class XpathRegressionEqualsHashCodeTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testHashCodeOnly() throws Exception {
+  void hashCodeOnly() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionEqualsHashCode2.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(EqualsHashCodeCheck.class);
@@ -83,7 +83,7 @@ public class XpathRegressionEqualsHashCodeTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testNestedCase() throws Exception {
+  void nestedCase() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionEqualsHashCodeNestedCase.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionExplicitInitializationTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionExplicitInitializationTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.ExplicitInitializationCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionExplicitInitializationTest extends AbstractXpathTestSupport {
+final class XpathRegressionExplicitInitializationTest extends AbstractXpathTestSupport {
 
   private final String checkName = ExplicitInitializationCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionExplicitInitializationTest extends AbstractXpathTest
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionExplicitInitializationOne.java"));
 
@@ -49,7 +49,7 @@ public class XpathRegressionExplicitInitializationTest extends AbstractXpathTest
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionExplicitInitializationOne']]"
                 + "/OBJBLOCK/VARIABLE_DEF/IDENT[@text='a']");
@@ -58,7 +58,7 @@ public class XpathRegressionExplicitInitializationTest extends AbstractXpathTest
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionExplicitInitializationTwo.java"));
 
@@ -74,7 +74,7 @@ public class XpathRegressionExplicitInitializationTest extends AbstractXpathTest
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionExplicitInitializationTwo']]"
                 + "/OBJBLOCK/VARIABLE_DEF/IDENT[@text='bar']");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionFallThroughTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionFallThroughTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionFallThroughTest extends AbstractXpathTestSupport {
+final class XpathRegressionFallThroughTest extends AbstractXpathTestSupport {
 
   private final String checkName = FallThroughCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionFallThroughTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionFallThroughOne.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(FallThroughCheck.class);
@@ -59,7 +59,7 @@ public class XpathRegressionFallThroughTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionFallThroughTwo.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(FallThroughCheck.class);
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionFinalClassTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionFinalClassTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionFinalClassTest extends AbstractXpathTestSupport {
+final class XpathRegressionFinalClassTest extends AbstractXpathTestSupport {
   private final String checkName = FinalClassCheck.class.getSimpleName();
 
   @Override
@@ -35,7 +35,7 @@ public class XpathRegressionFinalClassTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionFinalClass1.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(FinalClassCheck.class);
@@ -61,7 +61,7 @@ public class XpathRegressionFinalClassTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionFinalClass2.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(FinalClassCheck.class);
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionFinalLocalVariableTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionFinalLocalVariableTest.java
@@ -19,13 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.FinalLocalVariableCheck;
 import java.io.File;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionFinalLocalVariableTest extends AbstractXpathTestSupport {
+final class XpathRegressionFinalLocalVariableTest extends AbstractXpathTestSupport {
 
   private final String checkName = FinalLocalVariableCheck.class.getSimpleName();
 
@@ -35,7 +36,7 @@ public class XpathRegressionFinalLocalVariableTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionFinalLocalVariable1.java"));
 
@@ -47,7 +48,7 @@ public class XpathRegressionFinalLocalVariableTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        List.of(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionFinalLocalVariable1']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='testMethod']]"
@@ -57,7 +58,7 @@ public class XpathRegressionFinalLocalVariableTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionFinalLocalVariable2.java"));
 
@@ -69,7 +70,7 @@ public class XpathRegressionFinalLocalVariableTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        List.of(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionFinalLocalVariable2']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='method2']]/SLIST/"
@@ -79,7 +80,7 @@ public class XpathRegressionFinalLocalVariableTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionFinalLocalVariable3.java"));
 
@@ -91,7 +92,7 @@ public class XpathRegressionFinalLocalVariableTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        List.of(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionFinalLocalVariable3']]"
                 + "/OBJBLOCK/CLASS_DEF[./IDENT[@text='InnerClass']]"
@@ -102,7 +103,7 @@ public class XpathRegressionFinalLocalVariableTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testFour() throws Exception {
+  void four() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionFinalLocalVariable4.java"));
 
@@ -115,7 +116,7 @@ public class XpathRegressionFinalLocalVariableTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        List.of(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionFinalLocalVariable4']]"
                 + "/OBJBLOCK/CLASS_DEF[./IDENT[@text='InnerClass']]"
@@ -126,7 +127,7 @@ public class XpathRegressionFinalLocalVariableTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testFive() throws Exception {
+  void five() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionFinalLocalVariable5.java"));
 
@@ -139,7 +140,7 @@ public class XpathRegressionFinalLocalVariableTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        List.of(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionFinalLocalVariable5']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='method']]"
@@ -149,7 +150,7 @@ public class XpathRegressionFinalLocalVariableTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testSix() throws Exception {
+  void six() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionFinalLocalVariable6.java"));
 
@@ -162,7 +163,7 @@ public class XpathRegressionFinalLocalVariableTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        List.of(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionFinalLocalVariable6']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='method1']]"
@@ -172,7 +173,7 @@ public class XpathRegressionFinalLocalVariableTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testSeven() throws Exception {
+  void seven() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionFinalLocalVariable7.java"));
 
@@ -185,7 +186,7 @@ public class XpathRegressionFinalLocalVariableTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        List.of(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionFinalLocalVariable7']]"
                 + "/OBJBLOCK/CTOR_DEF[./IDENT"
@@ -196,7 +197,7 @@ public class XpathRegressionFinalLocalVariableTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testEight() throws Exception {
+  void eight() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionFinalLocalVariable8.java"));
 
@@ -209,7 +210,7 @@ public class XpathRegressionFinalLocalVariableTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        List.of(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionFinalLocalVariable8']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='checkCodeBlock']]"
@@ -219,7 +220,7 @@ public class XpathRegressionFinalLocalVariableTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testNine() throws Exception {
+  void nine() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionFinalLocalVariable9.java"));
 
@@ -231,7 +232,7 @@ public class XpathRegressionFinalLocalVariableTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        List.of(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionFinalLocalVariable9']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='checkCodeBlock']]/SLIST/LITERAL_TRY"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionFinalParametersTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionFinalParametersTest.java
@@ -19,13 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.FinalParametersCheck;
 import java.io.File;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionFinalParametersTest extends AbstractXpathTestSupport {
+final class XpathRegressionFinalParametersTest extends AbstractXpathTestSupport {
 
   private final String checkName = FinalParametersCheck.class.getSimpleName();
 
@@ -35,7 +36,7 @@ public class XpathRegressionFinalParametersTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionFinalParameters1.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(FinalParametersCheck.class);
@@ -46,7 +47,7 @@ public class XpathRegressionFinalParametersTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        List.of(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionFinalParameters1']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='method']]"
@@ -72,7 +73,7 @@ public class XpathRegressionFinalParametersTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionFinalParameters2.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(FinalParametersCheck.class);
@@ -85,7 +86,7 @@ public class XpathRegressionFinalParametersTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        List.of(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionFinalParameters2']]"
                 + "/OBJBLOCK/CTOR_DEF[./IDENT["
@@ -116,7 +117,7 @@ public class XpathRegressionFinalParametersTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionFinalParameters3.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(FinalParametersCheck.class);
@@ -129,7 +130,7 @@ public class XpathRegressionFinalParametersTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        List.of(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionFinalParameters3']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='createClass']]/SLIST/"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionGenericWhitespaceTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionGenericWhitespaceTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.GenericWhitespaceCheck;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionGenericWhitespaceTest extends AbstractXpathTestSupport {
+final class XpathRegressionGenericWhitespaceTest extends AbstractXpathTestSupport {
 
   private final String checkName = GenericWhitespaceCheck.class.getSimpleName();
 
@@ -37,7 +37,7 @@ public class XpathRegressionGenericWhitespaceTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testProcessEnd() throws Exception {
+  void processEnd() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionGenericWhitespaceEnd.java"));
 
@@ -50,7 +50,7 @@ public class XpathRegressionGenericWhitespaceTest extends AbstractXpathTestSuppo
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionGenericWhitespaceEnd']]/OBJBLOCK"
                 + "/METHOD_DEF[./IDENT[@text='bad']]"
@@ -61,7 +61,7 @@ public class XpathRegressionGenericWhitespaceTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testProcessNestedGenericsOne() throws Exception {
+  void processNestedGenericsOne() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionGenericWhitespaceNestedGenericsOne.java"));
 
@@ -74,7 +74,7 @@ public class XpathRegressionGenericWhitespaceTest extends AbstractXpathTestSuppo
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT["
                 + "@text='SuppressionXpathRegressionGenericWhitespaceNestedGenericsOne']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='bad']]/TYPE_PARAMETERS"
@@ -85,7 +85,7 @@ public class XpathRegressionGenericWhitespaceTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testProcessNestedGenericsTwo() throws Exception {
+  void processNestedGenericsTwo() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionGenericWhitespaceNestedGenericsTwo.java"));
 
@@ -98,7 +98,7 @@ public class XpathRegressionGenericWhitespaceTest extends AbstractXpathTestSuppo
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT["
                 + "@text='SuppressionXpathRegressionGenericWhitespaceNestedGenericsTwo']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='bad']]/TYPE_PARAMETERS"
@@ -109,7 +109,7 @@ public class XpathRegressionGenericWhitespaceTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testProcessNestedGenericsThree() throws Exception {
+  void processNestedGenericsThree() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionGenericWhitespaceNestedGenericsThree.java"));
 
@@ -122,7 +122,7 @@ public class XpathRegressionGenericWhitespaceTest extends AbstractXpathTestSuppo
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT["
                 + "@text='SuppressionXpathRegressionGenericWhitespaceNestedGenericsThree']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='bad']]/TYPE_PARAMETERS"
@@ -133,7 +133,7 @@ public class XpathRegressionGenericWhitespaceTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testProcessSingleGenericOne() throws Exception {
+  void processSingleGenericOne() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionGenericWhitespaceSingleGenericOne.java"));
 
@@ -146,7 +146,7 @@ public class XpathRegressionGenericWhitespaceTest extends AbstractXpathTestSuppo
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT["
                 + "@text='SuppressionXpathRegressionGenericWhitespaceSingleGenericOne']]"
                 + "/OBJBLOCK/VARIABLE_DEF[./IDENT[@text='bad']]/ASSIGN/EXPR/METHOD_CALL"
@@ -157,7 +157,7 @@ public class XpathRegressionGenericWhitespaceTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testProcessSingleGenericTwo() throws Exception {
+  void processSingleGenericTwo() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionGenericWhitespaceSingleGenericTwo.java"));
 
@@ -170,7 +170,7 @@ public class XpathRegressionGenericWhitespaceTest extends AbstractXpathTestSuppo
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT["
                 + "@text='SuppressionXpathRegressionGenericWhitespaceSingleGenericTwo']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='bad']]/TYPE_PARAMETERS/GENERIC_END");
@@ -179,7 +179,7 @@ public class XpathRegressionGenericWhitespaceTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testProcessStartOne() throws Exception {
+  void processStartOne() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionGenericWhitespaceStartOne.java"));
 
@@ -204,7 +204,7 @@ public class XpathRegressionGenericWhitespaceTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testProcessStartTwo() throws Exception {
+  void processStartTwo() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionGenericWhitespaceStartTwo.java"));
 
@@ -233,7 +233,7 @@ public class XpathRegressionGenericWhitespaceTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testProcessStartThree() throws Exception {
+  void processStartThree() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionGenericWhitespaceStartThree.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionHiddenFieldTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionHiddenFieldTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.HiddenFieldCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionHiddenFieldTest extends AbstractXpathTestSupport {
+final class XpathRegressionHiddenFieldTest extends AbstractXpathTestSupport {
 
   private final String checkName = HiddenFieldCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionHiddenFieldTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionHiddenFieldOne.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(HiddenFieldCheck.class);
@@ -46,7 +46,7 @@ public class XpathRegressionHiddenFieldTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionHiddenFieldOne']]/OBJBLOCK"
                 + "/INSTANCE_INIT/SLIST/EXPR/METHOD_CALL/ELIST/LAMBDA/PARAMETERS"
@@ -56,7 +56,7 @@ public class XpathRegressionHiddenFieldTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionHiddenFieldTwo.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(HiddenFieldCheck.class);
@@ -66,7 +66,7 @@ public class XpathRegressionHiddenFieldTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionHiddenFieldTwo']]/OBJBLOCK"
                 + "/METHOD_DEF[./IDENT[@text='method']]/PARAMETERS/PARAMETER_DEF"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionIllegalCatchTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionIllegalCatchTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.IllegalCatchCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionIllegalCatchTest extends AbstractXpathTestSupport {
+final class XpathRegressionIllegalCatchTest extends AbstractXpathTestSupport {
 
   private final String checkName = IllegalCatchCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionIllegalCatchTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionIllegalCatchOne.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(IllegalCatchCheck.class);
@@ -47,7 +47,7 @@ public class XpathRegressionIllegalCatchTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionIllegalCatchOne']]/OBJBLOCK"
                 + "/METHOD_DEF[./IDENT[@text='fun']]/SLIST"
@@ -57,7 +57,7 @@ public class XpathRegressionIllegalCatchTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionIllegalCatchTwo.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(IllegalCatchCheck.class);
@@ -69,7 +69,7 @@ public class XpathRegressionIllegalCatchTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionIllegalCatchTwo']]/OBJBLOCK"
                 + "/METHOD_DEF[./IDENT[@text='methodTwo']]/SLIST"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionIllegalIdentifierNameTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionIllegalIdentifierNameTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.naming.AbstractNameCheck;
 import com.puppycrawl.tools.checkstyle.checks.naming.IllegalIdentifierNameCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionIllegalIdentifierNameTest extends AbstractXpathTestSupport {
+final class XpathRegressionIllegalIdentifierNameTest extends AbstractXpathTestSupport {
 
   private final String checkName = IllegalIdentifierNameCheck.class.getSimpleName();
 
@@ -37,7 +37,7 @@ public class XpathRegressionIllegalIdentifierNameTest extends AbstractXpathTestS
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(
             getNonCompilablePath("SuppressionXpathRegressionIllegalIdentifierNameTestOne.java"));
@@ -56,7 +56,7 @@ public class XpathRegressionIllegalIdentifierNameTest extends AbstractXpathTestS
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/RECORD_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionIllegalIdentifierNameTestOne'"
                 + "]]/RECORD_COMPONENTS/RECORD_COMPONENT_DEF/IDENT[@text='yield']");
@@ -65,7 +65,7 @@ public class XpathRegressionIllegalIdentifierNameTest extends AbstractXpathTestS
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(
             getNonCompilablePath("SuppressionXpathRegressionIllegalIdentifierNameTestTwo.java"));
@@ -84,7 +84,7 @@ public class XpathRegressionIllegalIdentifierNameTest extends AbstractXpathTestS
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionIllegalIdentifierNameTestTwo']"
                 + "]/OBJBLOCK/METHOD_DEF[./IDENT[@text='foo']]/PARAMETERS/PARAMETER_DEF"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionIllegalImportTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionIllegalImportTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.imports.IllegalImportCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionIllegalImportTest extends AbstractXpathTestSupport {
+final class XpathRegressionIllegalImportTest extends AbstractXpathTestSupport {
 
   private final String checkName = IllegalImportCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionIllegalImportTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionIllegalImportOne.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(IllegalImportCheck.class);
     moduleConfig.addProperty("illegalPkgs", "java.util");
@@ -44,13 +44,13 @@ public class XpathRegressionIllegalImportTest extends AbstractXpathTestSupport {
       "3:1: "
           + getCheckMessage(IllegalImportCheck.class, IllegalImportCheck.MSG_KEY, "java.util.List"),
     };
-    final List<String> expectedXpathQueries = Collections.singletonList("/COMPILATION_UNIT/IMPORT");
+    final List<String> expectedXpathQueries = ImmutableList.of("/COMPILATION_UNIT/IMPORT");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionIllegalImportTwo.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(IllegalImportCheck.class);
 
@@ -61,8 +61,7 @@ public class XpathRegressionIllegalImportTest extends AbstractXpathTestSupport {
           + getCheckMessage(
               IllegalImportCheck.class, IllegalImportCheck.MSG_KEY, "java.lang.Math.pow"),
     };
-    final List<String> expectedXpathQueries =
-        Collections.singletonList("/COMPILATION_UNIT/STATIC_IMPORT");
+    final List<String> expectedXpathQueries = ImmutableList.of("/COMPILATION_UNIT/STATIC_IMPORT");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionIllegalThrowsTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionIllegalThrowsTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.IllegalThrowsCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionIllegalThrowsTest extends AbstractXpathTestSupport {
+final class XpathRegressionIllegalThrowsTest extends AbstractXpathTestSupport {
 
   private final String checkName = IllegalThrowsCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionIllegalThrowsTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionIllegalThrowsOne.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(IllegalThrowsCheck.class);
@@ -48,7 +48,7 @@ public class XpathRegressionIllegalThrowsTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionIllegalThrowsOne']]/OBJBLOCK"
                 + "/METHOD_DEF[./IDENT[@text='sayHello']]/LITERAL_THROWS"
@@ -58,7 +58,7 @@ public class XpathRegressionIllegalThrowsTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionIllegalThrowsTwo.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(IllegalThrowsCheck.class);
@@ -70,7 +70,7 @@ public class XpathRegressionIllegalThrowsTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionIllegalThrowsTwo']]/OBJBLOCK"
                 + "/METHOD_DEF[./IDENT[@text='methodTwo']]/LITERAL_THROWS"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionIllegalTokenTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionIllegalTokenTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.IllegalTokenCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionIllegalTokenTest extends AbstractXpathTestSupport {
+final class XpathRegressionIllegalTokenTest extends AbstractXpathTestSupport {
 
   private final String checkName = IllegalTokenCheck.class.getSimpleName();
 
@@ -36,14 +36,14 @@ public class XpathRegressionIllegalTokenTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionIllegalToken1.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(IllegalTokenCheck.class);
     final String[] expectedViolation = {
       "5:10: " + getCheckMessage(IllegalTokenCheck.class, IllegalTokenCheck.MSG_KEY, "outer:"),
     };
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text='SuppressionXpathRegressionIllegalToken1']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='myTest']]"
@@ -53,7 +53,7 @@ public class XpathRegressionIllegalTokenTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionIllegalToken2.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(IllegalTokenCheck.class);
 
@@ -63,7 +63,7 @@ public class XpathRegressionIllegalTokenTest extends AbstractXpathTestSupport {
       "4:10: " + getCheckMessage(IllegalTokenCheck.class, IllegalTokenCheck.MSG_KEY, "native"),
     };
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text='SuppressionXpathRegressionIllegalToken2']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='myTest']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionIllegalTokenTextTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionIllegalTokenTextTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.IllegalTokenTextCheck;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionIllegalTokenTextTest extends AbstractXpathTestSupport {
+final class XpathRegressionIllegalTokenTextTest extends AbstractXpathTestSupport {
 
   private final String checkName = IllegalTokenTextCheck.class.getSimpleName();
 
@@ -37,7 +37,7 @@ public class XpathRegressionIllegalTokenTextTest extends AbstractXpathTestSuppor
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionIllegalTokenText1.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(IllegalTokenTextCheck.class);
@@ -62,7 +62,7 @@ public class XpathRegressionIllegalTokenTextTest extends AbstractXpathTestSuppor
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionIllegalTokenText2.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(IllegalTokenTextCheck.class);
@@ -90,7 +90,7 @@ public class XpathRegressionIllegalTokenTextTest extends AbstractXpathTestSuppor
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionIllegalTokenText3.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(IllegalTokenTextCheck.class);
@@ -102,7 +102,7 @@ public class XpathRegressionIllegalTokenTextTest extends AbstractXpathTestSuppor
               IllegalTokenTextCheck.class, IllegalTokenTextCheck.MSG_KEY, "invalidIdentifier"),
     };
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/INTERFACE_DEF[./IDENT[@text='SuppressionXpathRegressionIllegalTokenText3']]"
                 + "/OBJBLOCK/METHOD_DEF/IDENT[@text='invalidIdentifier']");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionIllegalTypeTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionIllegalTypeTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.IllegalTypeCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionIllegalTypeTest extends AbstractXpathTestSupport {
+final class XpathRegressionIllegalTypeTest extends AbstractXpathTestSupport {
 
   private final String checkName = IllegalTypeCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionIllegalTypeTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionIllegalTypeOne.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(IllegalTypeCheck.class);
     moduleConfig.addProperty("tokens", "METHOD_DEF");
@@ -45,7 +45,7 @@ public class XpathRegressionIllegalTypeTest extends AbstractXpathTestSupport {
           + getCheckMessage(IllegalTypeCheck.class, IllegalTypeCheck.MSG_KEY, "java.util.HashSet"),
     };
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text='SuppressionXpathRegressionIllegalTypeOne']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='typeParam']]/TYPE_PARAMETERS/TYPE_PARAMETER"
@@ -56,7 +56,7 @@ public class XpathRegressionIllegalTypeTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionIllegalTypeTwo.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(IllegalTypeCheck.class);
 
@@ -66,7 +66,7 @@ public class XpathRegressionIllegalTypeTest extends AbstractXpathTestSupport {
       "6:20: " + getCheckMessage(IllegalTypeCheck.class, IllegalTypeCheck.MSG_KEY, "Boolean"),
     };
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT[@text='SuppressionXpathRegressionIllegalTypeTwo']"
                 + "]/OBJBLOCK/METHOD_DEF[./IDENT[@text='typeParam']]/TYPE_PARAMETERS/"
                 + "TYPE_PARAMETER[./IDENT[@text='T']]/TYPE_UPPER_BOUNDS/IDENT[@text='Boolean']");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionImportControlTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionImportControlTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.imports.ImportControlCheck;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionImportControlTest extends AbstractXpathTestSupport {
+final class XpathRegressionImportControlTest extends AbstractXpathTestSupport {
 
   private final String checkName = ImportControlCheck.class.getSimpleName();
 
@@ -37,7 +37,7 @@ public class XpathRegressionImportControlTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionImportControlOne.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(ImportControlCheck.class);
@@ -49,13 +49,13 @@ public class XpathRegressionImportControlTest extends AbstractXpathTestSupport {
               ImportControlCheck.class, ImportControlCheck.MSG_DISALLOWED, "java.util.Scanner"),
     };
 
-    final List<String> expectedXpathQueries = Collections.singletonList("/COMPILATION_UNIT/IMPORT");
+    final List<String> expectedXpathQueries = ImmutableList.of("/COMPILATION_UNIT/IMPORT");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionImportControlTwo.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(ImportControlCheck.class);
@@ -72,7 +72,7 @@ public class XpathRegressionImportControlTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionImportControlThree.java"));
 
@@ -89,7 +89,7 @@ public class XpathRegressionImportControlTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testFour() throws Exception {
+  void four() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionImportControlFour.java"));
 
@@ -103,7 +103,7 @@ public class XpathRegressionImportControlTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList("/COMPILATION_UNIT/IMPORT[./DOT/IDENT[@text='Scanner']]");
+        ImmutableList.of("/COMPILATION_UNIT/IMPORT[./DOT/IDENT[@text='Scanner']]");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionImportOrderTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionImportOrderTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.imports.ImportOrderCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionImportOrderTest extends AbstractXpathTestSupport {
+final class XpathRegressionImportOrderTest extends AbstractXpathTestSupport {
 
   private final String checkName = ImportOrderCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionImportOrderTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionImportOrderOne.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(ImportOrderCheck.class);
@@ -46,13 +46,13 @@ public class XpathRegressionImportOrderTest extends AbstractXpathTestSupport {
           + getCheckMessage(ImportOrderCheck.class, ImportOrderCheck.MSG_ORDERING, "java.util.Set"),
     };
 
-    final List<String> expectedXpathQueries = Collections.singletonList("/COMPILATION_UNIT/IMPORT");
+    final List<String> expectedXpathQueries = ImmutableList.of("/COMPILATION_UNIT/IMPORT");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionImportOrderTwo.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(ImportOrderCheck.class);
@@ -64,13 +64,13 @@ public class XpathRegressionImportOrderTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList("/COMPILATION_UNIT/IMPORT[./DOT/IDENT[@text='Set']]");
+        ImmutableList.of("/COMPILATION_UNIT/IMPORT[./DOT/IDENT[@text='Set']]");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionImportOrderThree.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(ImportOrderCheck.class);
@@ -83,13 +83,13 @@ public class XpathRegressionImportOrderTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList("/COMPILATION_UNIT/IMPORT[./DOT/DOT/IDENT[@text='org']]");
+        ImmutableList.of("/COMPILATION_UNIT/IMPORT[./DOT/DOT/IDENT[@text='org']]");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
 
   @Test
-  public void testFour() throws Exception {
+  void four() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionImportOrderFour.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(ImportOrderCheck.class);
@@ -101,14 +101,13 @@ public class XpathRegressionImportOrderTest extends AbstractXpathTestSupport {
               ImportOrderCheck.class, ImportOrderCheck.MSG_ORDERING, "java.lang.Math.PI"),
     };
 
-    final List<String> expectedXpathQueries =
-        Collections.singletonList("/COMPILATION_UNIT/STATIC_IMPORT");
+    final List<String> expectedXpathQueries = ImmutableList.of("/COMPILATION_UNIT/STATIC_IMPORT");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
 
   @Test
-  public void testFive() throws Exception {
+  void five() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionImportOrderFive.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(ImportOrderCheck.class);
@@ -121,7 +120,7 @@ public class XpathRegressionImportOrderTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList("/COMPILATION_UNIT/IMPORT[./DOT/IDENT[@text='Date']]");
+        ImmutableList.of("/COMPILATION_UNIT/IMPORT[./DOT/IDENT[@text='Date']]");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionIndentationTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionIndentationTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.indentation.IndentationCheck;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionIndentationTest extends AbstractXpathTestSupport {
+final class XpathRegressionIndentationTest extends AbstractXpathTestSupport {
   private final String checkName = IndentationCheck.class.getSimpleName();
 
   @Override
@@ -36,7 +36,7 @@ public class XpathRegressionIndentationTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionIndentationTestOne.java"));
 
@@ -67,7 +67,7 @@ public class XpathRegressionIndentationTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testBasicOffset() throws Exception {
+  void basicOffset() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionIndentationTestTwo.java"));
 
@@ -106,7 +106,7 @@ public class XpathRegressionIndentationTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testCaseIndent() throws Exception {
+  void caseIndent() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionIndentationTestThree.java"));
 
@@ -141,7 +141,7 @@ public class XpathRegressionIndentationTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testLambda() throws Exception {
+  void lambda() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionIndentationLambdaTest1.java"));
 
@@ -160,7 +160,7 @@ public class XpathRegressionIndentationTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionIndentationLambdaTest1"
                 + "']]/OBJBLOCK/METHOD_DEF[./IDENT[@text='test']]/SLIST/VARIABLE_DEF"
@@ -170,7 +170,7 @@ public class XpathRegressionIndentationTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testLambda2() throws Exception {
+  void lambda2() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionIndentationLambdaTest2.java"));
 
@@ -195,7 +195,7 @@ public class XpathRegressionIndentationTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionIndentationLambdaTest2']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='test']]/SLIST/VARIABLE_DEF["
@@ -205,7 +205,7 @@ public class XpathRegressionIndentationTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testIfWithNoCurlies() throws Exception {
+  void ifWithNoCurlies() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionIndentationIfWithoutCurly.java"));
 
@@ -226,7 +226,7 @@ public class XpathRegressionIndentationTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionIndentationIfWithoutCurly']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='test']]/SLIST/LITERAL_IF/EXPR/"
@@ -236,7 +236,7 @@ public class XpathRegressionIndentationTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testElseWithNoCurlies() throws Exception {
+  void elseWithNoCurlies() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionIndentationElseWithoutCurly.java"));
 
@@ -258,7 +258,7 @@ public class XpathRegressionIndentationTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionIndentationElseWithoutCurly']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='test']]/SLIST/LITERAL_IF/LITERAL_ELSE"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionInnerAssignmentTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionInnerAssignmentTest.java
@@ -19,6 +19,7 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.InnerAssignmentCheck;
 import java.io.File;
@@ -26,7 +27,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionInnerAssignmentTest extends AbstractXpathTestSupport {
+final class XpathRegressionInnerAssignmentTest extends AbstractXpathTestSupport {
 
   private final String checkName = InnerAssignmentCheck.class.getSimpleName();
 
@@ -36,7 +37,7 @@ public class XpathRegressionInnerAssignmentTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testFile1() throws Exception {
+  void file1() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionInnerAssignment1.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(InnerAssignmentCheck.class);
@@ -46,7 +47,7 @@ public class XpathRegressionInnerAssignmentTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        List.of(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text='SuppressionXpathRegressionInnerAssignment1']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='testMethod']]"
@@ -56,7 +57,7 @@ public class XpathRegressionInnerAssignmentTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testFile2() throws Exception {
+  void file2() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionInnerAssignment2.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(InnerAssignmentCheck.class);
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionInnerTypeLastTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionInnerTypeLastTest.java
@@ -28,7 +28,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionInnerTypeLastTest extends AbstractXpathTestSupport {
+final class XpathRegressionInnerTypeLastTest extends AbstractXpathTestSupport {
 
   private final String checkName = InnerTypeLastCheck.class.getSimpleName();
 
@@ -38,7 +38,7 @@ public class XpathRegressionInnerTypeLastTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionInnerTypeLastOne.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(InnerTypeLastCheck.class);
@@ -68,7 +68,7 @@ public class XpathRegressionInnerTypeLastTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
 
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionInnerTypeLastTwo.java"));
 
@@ -99,7 +99,7 @@ public class XpathRegressionInnerTypeLastTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
 
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionInnerTypeLastThree.java"));
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionInterfaceIsTypeTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionInterfaceIsTypeTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionInterfaceIsTypeTest extends AbstractXpathTestSupport {
+final class XpathRegressionInterfaceIsTypeTest extends AbstractXpathTestSupport {
 
   private final String checkName = InterfaceIsTypeCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionInterfaceIsTypeTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionInterfaceIsType1.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(InterfaceIsTypeCheck.class);
@@ -59,7 +59,7 @@ public class XpathRegressionInterfaceIsTypeTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionInterfaceIsType2.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(InterfaceIsTypeCheck.class);
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionInterfaceMemberImpliedModifierTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionInterfaceMemberImpliedModifierTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionInterfaceMemberImpliedModifierTest extends AbstractXpathTestSupport {
+final class XpathRegressionInterfaceMemberImpliedModifierTest extends AbstractXpathTestSupport {
 
   @Override
   protected String getCheckName() {
@@ -34,7 +34,7 @@ public class XpathRegressionInterfaceMemberImpliedModifierTest extends AbstractX
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionInterfaceMemberImpliedModifier1.java"));
 
@@ -67,7 +67,7 @@ public class XpathRegressionInterfaceMemberImpliedModifierTest extends AbstractX
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionInterfaceMemberImpliedModifier2.java"));
 
@@ -100,7 +100,7 @@ public class XpathRegressionInterfaceMemberImpliedModifierTest extends AbstractX
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionInterfaceMemberImpliedModifier3.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionInvalidJavadocPositionTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionInvalidJavadocPositionTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.javadoc.InvalidJavadocPositionCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionInvalidJavadocPositionTest extends AbstractXpathTestSupport {
+final class XpathRegressionInvalidJavadocPositionTest extends AbstractXpathTestSupport {
 
   private final String checkName = InvalidJavadocPositionCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionInvalidJavadocPositionTest extends AbstractXpathTest
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionInvalidJavadocPositionOne.java"));
 
@@ -48,7 +48,7 @@ public class XpathRegressionInvalidJavadocPositionTest extends AbstractXpathTest
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionInvalidJavadocPositionOne']]"
                 + "/MODIFIERS/BLOCK_COMMENT_BEGIN[./COMMENT_CONTENT"
@@ -58,7 +58,7 @@ public class XpathRegressionInvalidJavadocPositionTest extends AbstractXpathTest
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionInvalidJavadocPositionTwo.java"));
 
@@ -70,7 +70,7 @@ public class XpathRegressionInvalidJavadocPositionTest extends AbstractXpathTest
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionInvalidJavadocPositionTwo']]"
                 + "/OBJBLOCK/BLOCK_COMMENT_BEGIN[./COMMENT_CONTENT"
@@ -80,7 +80,7 @@ public class XpathRegressionInvalidJavadocPositionTest extends AbstractXpathTest
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionInvalidJavadocPositionThree.java"));
 
@@ -92,7 +92,7 @@ public class XpathRegressionInvalidJavadocPositionTest extends AbstractXpathTest
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionInvalidJavadocPositionThree']]/"
                 + "OBJBLOCK/BLOCK_COMMENT_BEGIN[./COMMENT_CONTENT"
@@ -102,7 +102,7 @@ public class XpathRegressionInvalidJavadocPositionTest extends AbstractXpathTest
   }
 
   @Test
-  public void testFour() throws Exception {
+  void four() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionInvalidJavadocPositionFour.java"));
 
@@ -114,7 +114,7 @@ public class XpathRegressionInvalidJavadocPositionTest extends AbstractXpathTest
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionInvalidJavadocPositionFour']]"
                 + "/OBJBLOCK/BLOCK_COMMENT_BEGIN[./COMMENT_CONTENT"
@@ -124,7 +124,7 @@ public class XpathRegressionInvalidJavadocPositionTest extends AbstractXpathTest
   }
 
   @Test
-  public void testFive() throws Exception {
+  void five() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionInvalidJavadocPositionFive.java"));
 
@@ -136,7 +136,7 @@ public class XpathRegressionInvalidJavadocPositionTest extends AbstractXpathTest
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionInvalidJavadocPositionFive']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='foo']]"
@@ -147,7 +147,7 @@ public class XpathRegressionInvalidJavadocPositionTest extends AbstractXpathTest
   }
 
   @Test
-  public void testSix() throws Exception {
+  void six() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionInvalidJavadocPositionSix.java"));
 
@@ -159,7 +159,7 @@ public class XpathRegressionInvalidJavadocPositionTest extends AbstractXpathTest
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionInvalidJavadocPositionSix']]"
                 + "/OBJBLOCK/BLOCK_COMMENT_BEGIN[./COMMENT_CONTENT"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionJavaNCSSTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionJavaNCSSTest.java
@@ -19,6 +19,7 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.metrics.JavaNCSSCheck;
 import java.io.File;
@@ -26,7 +27,7 @@ import java.util.List;
 import org.junit.jupiter.api.Test;
 
 // -@cs[AbbreviationAsWordInName] Test should be named as its main class.
-public class XpathRegressionJavaNCSSTest extends AbstractXpathTestSupport {
+final class XpathRegressionJavaNCSSTest extends AbstractXpathTestSupport {
 
   private final String checkName = JavaNCSSCheck.class.getSimpleName();
 
@@ -36,7 +37,7 @@ public class XpathRegressionJavaNCSSTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionJavaNCSSOne.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(JavaNCSSCheck.class);
@@ -46,7 +47,7 @@ public class XpathRegressionJavaNCSSTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        List.of(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionJavaNCSSOne']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='test']]",
@@ -61,7 +62,7 @@ public class XpathRegressionJavaNCSSTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionJavaNCSSTwo.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(JavaNCSSCheck.class);
@@ -73,7 +74,7 @@ public class XpathRegressionJavaNCSSTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        List.of(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionJavaNCSSTwo']]",
             "/COMPILATION_UNIT/CLASS_DEF"
@@ -86,7 +87,7 @@ public class XpathRegressionJavaNCSSTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionJavaNCSSThree.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(JavaNCSSCheck.class);
@@ -98,7 +99,7 @@ public class XpathRegressionJavaNCSSTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        List.of("/COMPILATION_UNIT", "/COMPILATION_UNIT/PACKAGE_DEF");
+        ImmutableList.of("/COMPILATION_UNIT", "/COMPILATION_UNIT/PACKAGE_DEF");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionJavadocContentLocationTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionJavadocContentLocationTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.javadoc.JavadocContentLocationCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionJavadocContentLocationTest extends AbstractXpathTestSupport {
+final class XpathRegressionJavadocContentLocationTest extends AbstractXpathTestSupport {
 
   private final String checkName = JavadocContentLocationCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionJavadocContentLocationTest extends AbstractXpathTest
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionJavadocContentLocationOne.java"));
 
@@ -50,7 +50,7 @@ public class XpathRegressionJavadocContentLocationTest extends AbstractXpathTest
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/INTERFACE_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionJavadocContentLocationOne']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='test']]/TYPE/BLOCK_COMMENT_BEGIN"
@@ -60,7 +60,7 @@ public class XpathRegressionJavadocContentLocationTest extends AbstractXpathTest
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionJavadocContentLocationTwo.java"));
 
@@ -76,7 +76,7 @@ public class XpathRegressionJavadocContentLocationTest extends AbstractXpathTest
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/INTERFACE_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionJavadocContentLocationTwo']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='test']]/TYPE/BLOCK_COMMENT_BEGIN"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionJavadocMethodTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionJavadocMethodTest.java
@@ -22,15 +22,15 @@ package org.checkstyle.suppressionxpathfilter;
 import static com.puppycrawl.tools.checkstyle.checks.javadoc.JavadocMethodCheck.MSG_EXPECTED_TAG;
 import static com.puppycrawl.tools.checkstyle.checks.javadoc.JavadocMethodCheck.MSG_INVALID_INHERIT_DOC;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.javadoc.JavadocMethodCheck;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionJavadocMethodTest extends AbstractXpathTestSupport {
+final class XpathRegressionJavadocMethodTest extends AbstractXpathTestSupport {
 
   private final String checkName = JavadocMethodCheck.class.getSimpleName();
 
@@ -40,7 +40,7 @@ public class XpathRegressionJavadocMethodTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionJavadocMethodOne.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(JavadocMethodCheck.class);
@@ -66,7 +66,7 @@ public class XpathRegressionJavadocMethodTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionJavadocMethodTwo.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(JavadocMethodCheck.class);
@@ -76,7 +76,7 @@ public class XpathRegressionJavadocMethodTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionJavadocMethodTwo']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='checkParam']]/PARAMETERS"
@@ -86,7 +86,7 @@ public class XpathRegressionJavadocMethodTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionJavadocMethodThree.java"));
 
@@ -111,7 +111,7 @@ public class XpathRegressionJavadocMethodTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testFour() throws Exception {
+  void four() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionJavadocMethodFour.java"));
 
@@ -125,7 +125,7 @@ public class XpathRegressionJavadocMethodTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionJavadocMethodFour']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='foo']]"
@@ -135,7 +135,7 @@ public class XpathRegressionJavadocMethodTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testFive() throws Exception {
+  void five() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionJavadocMethodFive.java"));
 
@@ -153,7 +153,7 @@ public class XpathRegressionJavadocMethodTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionJavadocMethodFive']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='bar']]/SLIST"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionJavadocTypeTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionJavadocTypeTest.java
@@ -30,7 +30,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionJavadocTypeTest extends AbstractXpathTestSupport {
+final class XpathRegressionJavadocTypeTest extends AbstractXpathTestSupport {
 
   private final String checkName = JavadocTypeCheck.class.getSimpleName();
 
@@ -40,7 +40,7 @@ public class XpathRegressionJavadocTypeTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionJavadocTypeOne.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(JavadocTypeCheck.class);
@@ -66,7 +66,7 @@ public class XpathRegressionJavadocTypeTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionJavadocTypeTwo.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(JavadocTypeCheck.class);
@@ -91,7 +91,7 @@ public class XpathRegressionJavadocTypeTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionJavadocTypeThree.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(JavadocTypeCheck.class);
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionJavadocVariableTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionJavadocVariableTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionJavadocVariableTest extends AbstractXpathTestSupport {
+final class XpathRegressionJavadocVariableTest extends AbstractXpathTestSupport {
 
   private final String checkName = JavadocVariableCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionJavadocVariableTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionJavadocVariableOne.java"));
 
@@ -63,7 +63,7 @@ public class XpathRegressionJavadocVariableTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionJavadocVariableTwo.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionLambdaBodyLengthTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionLambdaBodyLengthTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.sizes.LambdaBodyLengthCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionLambdaBodyLengthTest extends AbstractXpathTestSupport {
+final class XpathRegressionLambdaBodyLengthTest extends AbstractXpathTestSupport {
 
   private static final Class<LambdaBodyLengthCheck> CLASS = LambdaBodyLengthCheck.class;
 
@@ -36,7 +36,7 @@ public class XpathRegressionLambdaBodyLengthTest extends AbstractXpathTestSuppor
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionLambdaBodyLength1.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(CLASS);
@@ -45,7 +45,7 @@ public class XpathRegressionLambdaBodyLengthTest extends AbstractXpathTestSuppor
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionLambdaBodyLength1']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='test']]/SLIST"
@@ -55,7 +55,7 @@ public class XpathRegressionLambdaBodyLengthTest extends AbstractXpathTestSuppor
   }
 
   @Test
-  public void testMaxIsNotDefault() throws Exception {
+  void maxIsNotDefault() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionLambdaBodyLength2.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(CLASS);
@@ -65,7 +65,7 @@ public class XpathRegressionLambdaBodyLengthTest extends AbstractXpathTestSuppor
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionLambdaBodyLength2']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='test']]/SLIST"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionLambdaParameterNameTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionLambdaParameterNameTest.java
@@ -19,16 +19,16 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.naming.AbstractNameCheck;
 import com.puppycrawl.tools.checkstyle.checks.naming.LambdaParameterNameCheck;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionLambdaParameterNameTest extends AbstractXpathTestSupport {
+final class XpathRegressionLambdaParameterNameTest extends AbstractXpathTestSupport {
 
   private final String checkName = LambdaParameterNameCheck.class.getSimpleName();
 
@@ -38,7 +38,7 @@ public class XpathRegressionLambdaParameterNameTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionLambdaParameterName1.java"));
 
@@ -55,7 +55,7 @@ public class XpathRegressionLambdaParameterNameTest extends AbstractXpathTestSup
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionLambdaParameterName1']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='test']]/SLIST/VARIABLE_DEF["
@@ -65,7 +65,7 @@ public class XpathRegressionLambdaParameterNameTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionLambdaParameterName2.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionLeftCurlyTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionLeftCurlyTest.java
@@ -19,16 +19,16 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.blocks.LeftCurlyCheck;
 import com.puppycrawl.tools.checkstyle.checks.blocks.LeftCurlyOption;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionLeftCurlyTest extends AbstractXpathTestSupport {
+final class XpathRegressionLeftCurlyTest extends AbstractXpathTestSupport {
 
   private final String checkName = LeftCurlyCheck.class.getSimpleName();
 
@@ -38,7 +38,7 @@ public class XpathRegressionLeftCurlyTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionLeftCurlyOne.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(LeftCurlyCheck.class);
@@ -58,7 +58,7 @@ public class XpathRegressionLeftCurlyTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionLeftCurlyTwo.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(LeftCurlyCheck.class);
@@ -79,7 +79,7 @@ public class XpathRegressionLeftCurlyTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionLeftCurlyThree.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(LeftCurlyCheck.class);
@@ -90,7 +90,7 @@ public class XpathRegressionLeftCurlyTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionLeftCurlyThree']]/OBJBLOCK"
                 + "/METHOD_DEF[./IDENT[@text='sample']]/SLIST/LITERAL_IF/SLIST");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMagicNumberTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMagicNumberTest.java
@@ -19,6 +19,7 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.MagicNumberCheck;
 import java.io.File;
@@ -26,7 +27,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionMagicNumberTest extends AbstractXpathTestSupport {
+final class XpathRegressionMagicNumberTest extends AbstractXpathTestSupport {
 
   @Override
   protected String getCheckName() {
@@ -34,7 +35,7 @@ public class XpathRegressionMagicNumberTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testVariable() throws Exception {
+  void variable() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMagicNumberVariable.java"));
 
@@ -59,7 +60,7 @@ public class XpathRegressionMagicNumberTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testMethodDef() throws Exception {
+  void methodDef() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMagicNumberMethodDef.java"));
 
@@ -85,7 +86,7 @@ public class XpathRegressionMagicNumberTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testAnotherVariable() throws Exception {
+  void anotherVariable() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMagicNumberAnotherVariable.java"));
 
@@ -96,7 +97,7 @@ public class XpathRegressionMagicNumberTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        List.of(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionMagicNumberAnotherVariable']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='performOperation']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMatchXpathTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMatchXpathTest.java
@@ -19,16 +19,16 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.IllegalTokenCheck;
 import com.puppycrawl.tools.checkstyle.checks.coding.MatchXpathCheck;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionMatchXpathTest extends AbstractXpathTestSupport {
+final class XpathRegressionMatchXpathTest extends AbstractXpathTestSupport {
 
   private final String checkName = MatchXpathCheck.class.getSimpleName();
 
@@ -38,7 +38,7 @@ public class XpathRegressionMatchXpathTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionMatchXpathOne.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(MatchXpathCheck.class);
@@ -61,7 +61,7 @@ public class XpathRegressionMatchXpathTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionMatchXpathTwo.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(MatchXpathCheck.class);
@@ -75,7 +75,7 @@ public class XpathRegressionMatchXpathTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionMatchXpathTwo']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='func1']]"
@@ -85,7 +85,7 @@ public class XpathRegressionMatchXpathTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testEncodedQuoteString() throws Exception {
+  void encodedQuoteString() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMatchXpathEncodedQuoteString.java"));
 
@@ -113,7 +113,7 @@ public class XpathRegressionMatchXpathTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testEncodedLessString() throws Exception {
+  void encodedLessString() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMatchXpathEncodedLessString.java"));
 
@@ -140,7 +140,7 @@ public class XpathRegressionMatchXpathTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testEncodedNewLineString() throws Exception {
+  void encodedNewLineString() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMatchXpathEncodedNewLineString.java"));
 
@@ -167,7 +167,7 @@ public class XpathRegressionMatchXpathTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testGreaterString() throws Exception {
+  void greaterString() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMatchXpathEncodedGreaterString.java"));
 
@@ -194,7 +194,7 @@ public class XpathRegressionMatchXpathTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testEncodedAmpString() throws Exception {
+  void encodedAmpString() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMatchXpathEncodedAmpString.java"));
 
@@ -221,7 +221,7 @@ public class XpathRegressionMatchXpathTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testEncodedAposString() throws Exception {
+  void encodedAposString() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMatchXpathEncodedAposString.java"));
 
@@ -249,7 +249,7 @@ public class XpathRegressionMatchXpathTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testEncodedCarriageString() throws Exception {
+  void encodedCarriageString() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMatchXpathEncodedCarriageString.java"));
 
@@ -277,7 +277,7 @@ public class XpathRegressionMatchXpathTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testEncodedAmpersandChars() throws Exception {
+  void encodedAmpersandChars() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMatchXpathEncodedAmpChar.java"));
 
@@ -307,7 +307,7 @@ public class XpathRegressionMatchXpathTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testEncodedQuoteChar() throws Exception {
+  void encodedQuoteChar() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMatchXpathEncodedQuotChar.java"));
 
@@ -334,7 +334,7 @@ public class XpathRegressionMatchXpathTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testEncodedLessChar() throws Exception {
+  void encodedLessChar() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMatchXpathEncodedLessChar.java"));
 
@@ -361,7 +361,7 @@ public class XpathRegressionMatchXpathTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testEncodedAposChar() throws Exception {
+  void encodedAposChar() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMatchXpathEncodedAposChar.java"));
 
@@ -388,7 +388,7 @@ public class XpathRegressionMatchXpathTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testEncodedGreaterChar() throws Exception {
+  void encodedGreaterChar() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMatchXpathEncodedGreaterChar.java"));
 
@@ -417,7 +417,7 @@ public class XpathRegressionMatchXpathTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testFollowing() throws Exception {
+  void following() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionMatchXpathThree.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(MatchXpathCheck.class);
@@ -428,7 +428,7 @@ public class XpathRegressionMatchXpathTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text='SuppressionXpathRegressionMatchXpathThree']]"
                 + "/OBJBLOCK/RCURLY");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMemberNameTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMemberNameTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.naming.AbstractNameCheck;
 import com.puppycrawl.tools.checkstyle.checks.naming.MemberNameCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionMemberNameTest extends AbstractXpathTestSupport {
+final class XpathRegressionMemberNameTest extends AbstractXpathTestSupport {
 
   private final String checkName = MemberNameCheck.class.getSimpleName();
 
@@ -37,7 +37,7 @@ public class XpathRegressionMemberNameTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void test1() throws Exception {
+  void test1() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionMemberName1.java"));
 
     final String pattern = "^[a-z][a-zA-Z0-9]*$";
@@ -50,7 +50,7 @@ public class XpathRegressionMemberNameTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text"
                 + "='SuppressionXpathRegressionMemberName1']]"
@@ -59,7 +59,7 @@ public class XpathRegressionMemberNameTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void test2() throws Exception {
+  void test2() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionMemberName2.java"));
 
     final String pattern = "^m[A-Z][a-zA-Z0-9]*$";
@@ -75,7 +75,7 @@ public class XpathRegressionMemberNameTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text"
                 + "='SuppressionXpathRegressionMemberName2']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMethodCountTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMethodCountTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionMethodCountTest extends AbstractXpathTestSupport {
+final class XpathRegressionMethodCountTest extends AbstractXpathTestSupport {
 
   @Override
   protected String getCheckName() {
@@ -34,7 +34,7 @@ public class XpathRegressionMethodCountTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionMethodCount1.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(MethodCountCheck.class);
@@ -59,7 +59,7 @@ public class XpathRegressionMethodCountTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionMethodCount2.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(MethodCountCheck.class);
@@ -84,7 +84,7 @@ public class XpathRegressionMethodCountTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionMethodCount1.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(MethodCountCheck.class);
@@ -109,7 +109,7 @@ public class XpathRegressionMethodCountTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testFour() throws Exception {
+  void four() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionMethodCount3.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(MethodCountCheck.class);
@@ -135,7 +135,7 @@ public class XpathRegressionMethodCountTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testFive() throws Exception {
+  void five() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionMethodCount4.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(MethodCountCheck.class);
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMethodNameTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMethodNameTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.naming.AbstractNameCheck;
 import com.puppycrawl.tools.checkstyle.checks.naming.MethodNameCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionMethodNameTest extends AbstractXpathTestSupport {
+final class XpathRegressionMethodNameTest extends AbstractXpathTestSupport {
 
   private final String checkName = MethodNameCheck.class.getSimpleName();
 
@@ -37,7 +37,7 @@ public class XpathRegressionMethodNameTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void test1() throws Exception {
+  void test1() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionMethodName1.java"));
 
     final String pattern = "^[a-z][a-zA-Z0-9]*$";
@@ -53,7 +53,7 @@ public class XpathRegressionMethodNameTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text"
                 + "='SuppressionXpathRegressionMethodName1']]"
@@ -62,7 +62,7 @@ public class XpathRegressionMethodNameTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void test2() throws Exception {
+  void test2() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionMethodName2.java"));
 
     final String pattern = "^[a-z](_?[a-zA-Z0-9]+)*$";
@@ -76,7 +76,7 @@ public class XpathRegressionMethodNameTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text"
                 + "='SuppressionXpathRegressionMethodName2']]"
@@ -86,7 +86,7 @@ public class XpathRegressionMethodNameTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void test3() throws Exception {
+  void test3() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionMethodName3.java"));
 
     final String pattern = "^[a-z](_?[a-zA-Z0-9]+)*$";
@@ -102,7 +102,7 @@ public class XpathRegressionMethodNameTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/INTERFACE_DEF[./IDENT[@text='Check']]"
                 + "/OBJBLOCK/METHOD_DEF/IDENT[@text='ThirdMethod']");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMethodParamPadTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMethodParamPadTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.MethodParamPadCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionMethodParamPadTest extends AbstractXpathTestSupport {
+final class XpathRegressionMethodParamPadTest extends AbstractXpathTestSupport {
 
   private final String checkName = MethodParamPadCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionMethodParamPadTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMethodParamPadOne.java"));
 
@@ -48,7 +48,7 @@ public class XpathRegressionMethodParamPadTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionMethodParamPadOne']]/OBJBLOCK"
                 + "/METHOD_DEF[./IDENT[@text='InputMethodParamPad']]/LPAREN");
@@ -57,7 +57,7 @@ public class XpathRegressionMethodParamPadTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMethodParamPadTwo.java"));
 
@@ -69,7 +69,7 @@ public class XpathRegressionMethodParamPadTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionMethodParamPadTwo']]/OBJBLOCK"
                 + "/METHOD_DEF[./IDENT[@text='sayHello']]/LPAREN");
@@ -78,7 +78,7 @@ public class XpathRegressionMethodParamPadTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMethodParamPadThree.java"));
 
@@ -92,7 +92,7 @@ public class XpathRegressionMethodParamPadTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionMethodParamPadThree']]/OBJBLOCK"
                 + "/METHOD_DEF[./IDENT[@text='sayHello']]/LPAREN");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMissingCtorTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMissingCtorTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionMissingCtorTest extends AbstractXpathTestSupport {
+final class XpathRegressionMissingCtorTest extends AbstractXpathTestSupport {
 
   private final String checkName = MissingCtorCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionMissingCtorTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionMissingCtor1.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(MissingCtorCheck.class);
@@ -58,7 +58,7 @@ public class XpathRegressionMissingCtorTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionMissingCtor2.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(MissingCtorCheck.class);
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMissingJavadocMethodTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMissingJavadocMethodTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionMissingJavadocMethodTest extends AbstractXpathTestSupport {
+final class XpathRegressionMissingJavadocMethodTest extends AbstractXpathTestSupport {
 
   @Override
   protected String getCheckName() {
@@ -34,7 +34,7 @@ public class XpathRegressionMissingJavadocMethodTest extends AbstractXpathTestSu
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMissingJavadocMethod1.java"));
 
@@ -68,7 +68,7 @@ public class XpathRegressionMissingJavadocMethodTest extends AbstractXpathTestSu
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMissingJavadocMethod2.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMissingJavadocPackageTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMissingJavadocPackageTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionMissingJavadocPackageTest extends AbstractXpathTestSupport {
+final class XpathRegressionMissingJavadocPackageTest extends AbstractXpathTestSupport {
 
   private final String checkName = MissingJavadocPackageCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionMissingJavadocPackageTest extends AbstractXpathTestS
   }
 
   @Test
-  public void testBlockComment() throws Exception {
+  void blockComment() throws Exception {
     final File fileToProcess = new File(getPath("blockcomment/package-info.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(MissingJavadocPackageCheck.class);
@@ -53,7 +53,7 @@ public class XpathRegressionMissingJavadocPackageTest extends AbstractXpathTestS
   }
 
   @Test
-  public void testNoJavadoc() throws Exception {
+  void noJavadoc() throws Exception {
     final File fileToProcess = new File(getPath("nojavadoc/package-info.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(MissingJavadocPackageCheck.class);
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMissingJavadocTypeTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMissingJavadocTypeTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionMissingJavadocTypeTest extends AbstractXpathTestSupport {
+final class XpathRegressionMissingJavadocTypeTest extends AbstractXpathTestSupport {
 
   private final String checkName = MissingJavadocTypeCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionMissingJavadocTypeTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testClass() throws Exception {
+  void testClass() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMissingJavadocTypeClass.java"));
 
@@ -65,7 +65,7 @@ public class XpathRegressionMissingJavadocTypeTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testScope() throws Exception {
+  void scope() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMissingJavadocTypeScope.java"));
 
@@ -96,7 +96,7 @@ public class XpathRegressionMissingJavadocTypeTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testExcluded() throws Exception {
+  void excluded() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMissingJavadocTypeExcluded.java"));
 
@@ -128,7 +128,7 @@ public class XpathRegressionMissingJavadocTypeTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testAnnotation() throws Exception {
+  void annotation() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMissingJavadocTypeAnnotation.java"));
 
@@ -164,7 +164,7 @@ public class XpathRegressionMissingJavadocTypeTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testToken() throws Exception {
+  void token() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMissingJavadocTypeToken.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMissingOverrideTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMissingOverrideTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionMissingOverrideTest extends AbstractXpathTestSupport {
+final class XpathRegressionMissingOverrideTest extends AbstractXpathTestSupport {
 
   private final String checkName = MissingOverrideCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionMissingOverrideTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testClass() throws Exception {
+  void testClass() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMissingOverrideClass.java"));
 
@@ -64,7 +64,7 @@ public class XpathRegressionMissingOverrideTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testInterface() throws Exception {
+  void testInterface() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMissingOverrideInterface.java"));
 
@@ -95,7 +95,7 @@ public class XpathRegressionMissingOverrideTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testAnonymous() throws Exception {
+  void anonymous() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMissingOverrideAnonymous.java"));
 
@@ -129,7 +129,7 @@ public class XpathRegressionMissingOverrideTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testInheritDocInvalid1() throws Exception {
+  void inheritDocInvalid1() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMissingOverrideInheritDocInvalid1.java"));
 
@@ -159,7 +159,7 @@ public class XpathRegressionMissingOverrideTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testInheritDocInvalid2() throws Exception {
+  void inheritDocInvalid2() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMissingOverrideInheritDocInvalid2.java"));
 
@@ -189,7 +189,7 @@ public class XpathRegressionMissingOverrideTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testJavaFiveCompatibility1() throws Exception {
+  void javaFiveCompatibility1() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMissingOverrideClass.java"));
 
@@ -218,7 +218,7 @@ public class XpathRegressionMissingOverrideTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testJavaFiveCompatibility2() throws Exception {
+  void javaFiveCompatibility2() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMissingOverrideInterface.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMissingSwitchDefaultTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMissingSwitchDefaultTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.MissingSwitchDefaultCheck;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionMissingSwitchDefaultTest extends AbstractXpathTestSupport {
+final class XpathRegressionMissingSwitchDefaultTest extends AbstractXpathTestSupport {
 
   private final Class<MissingSwitchDefaultCheck> clss = MissingSwitchDefaultCheck.class;
 
@@ -37,7 +37,7 @@ public class XpathRegressionMissingSwitchDefaultTest extends AbstractXpathTestSu
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMissingSwitchDefaultOne.java"));
 
@@ -47,7 +47,7 @@ public class XpathRegressionMissingSwitchDefaultTest extends AbstractXpathTestSu
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionMissingSwitchDefaultOne']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='test1']]"
@@ -57,7 +57,7 @@ public class XpathRegressionMissingSwitchDefaultTest extends AbstractXpathTestSu
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMissingSwitchDefaultTwo.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionModifierOrderTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionModifierOrderTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.modifier.ModifierOrderCheck;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionModifierOrderTest extends AbstractXpathTestSupport {
+final class XpathRegressionModifierOrderTest extends AbstractXpathTestSupport {
 
   private final Class<ModifierOrderCheck> clazz = ModifierOrderCheck.class;
 
@@ -37,7 +37,7 @@ public class XpathRegressionModifierOrderTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testMethod() throws Exception {
+  void method() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionModifierOrderMethod.java"));
 
@@ -63,7 +63,7 @@ public class XpathRegressionModifierOrderTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testVariable() throws Exception {
+  void variable() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionModifierOrderVariable.java"));
 
@@ -74,7 +74,7 @@ public class XpathRegressionModifierOrderTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionModifierOrderVariable']]"
                 + "/OBJBLOCK/VARIABLE_DEF[./IDENT[@text='var']]/MODIFIERS/LITERAL_PRIVATE");
@@ -83,7 +83,7 @@ public class XpathRegressionModifierOrderTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testAnnotation() throws Exception {
+  void annotation() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionModifierOrderAnnotation.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMultipleVariableDeclarationsTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionMultipleVariableDeclarationsTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionMultipleVariableDeclarationsTest extends AbstractXpathTestSupport {
+final class XpathRegressionMultipleVariableDeclarationsTest extends AbstractXpathTestSupport {
 
   private final String checkName = MultipleVariableDeclarationsCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionMultipleVariableDeclarationsTest extends AbstractXpa
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMultipleVariableDeclarationsOne.java"));
 
@@ -81,7 +81,7 @@ public class XpathRegressionMultipleVariableDeclarationsTest extends AbstractXpa
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionMultipleVariableDeclarationsTwo.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNPathComplexityTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNPathComplexityTest.java
@@ -19,16 +19,16 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.metrics.NPathComplexityCheck;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
 // -@cs[AbbreviationAsWordInName] Test should be named as its main class.
-public class XpathRegressionNPathComplexityTest extends AbstractXpathTestSupport {
+final class XpathRegressionNPathComplexityTest extends AbstractXpathTestSupport {
 
   private final String checkName = NPathComplexityCheck.class.getSimpleName();
 
@@ -38,7 +38,7 @@ public class XpathRegressionNPathComplexityTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionNPathComplexityOne.java"));
 
@@ -65,7 +65,7 @@ public class XpathRegressionNPathComplexityTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionNPathComplexityTwo.java"));
 
@@ -77,7 +77,7 @@ public class XpathRegressionNPathComplexityTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionNPathComplexityTwo']]"
                 + "/OBJBLOCK/STATIC_INIT");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNeedBracesTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNeedBracesTest.java
@@ -21,14 +21,14 @@ package org.checkstyle.suppressionxpathfilter;
 
 import static com.puppycrawl.tools.checkstyle.checks.blocks.NeedBracesCheck.MSG_KEY_NEED_BRACES;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.blocks.NeedBracesCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionNeedBracesTest extends AbstractXpathTestSupport {
+final class XpathRegressionNeedBracesTest extends AbstractXpathTestSupport {
   private final String checkName = NeedBracesCheck.class.getSimpleName();
 
   @Override
@@ -37,7 +37,7 @@ public class XpathRegressionNeedBracesTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testDo() throws Exception {
+  void testDo() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionNeedBracesDo.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(NeedBracesCheck.class);
@@ -47,7 +47,7 @@ public class XpathRegressionNeedBracesTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionNeedBracesDo']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='test']]/SLIST/LITERAL_DO");
@@ -56,7 +56,7 @@ public class XpathRegressionNeedBracesTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testSingleLine() throws Exception {
+  void singleLine() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionNeedBracesSingleLine.java"));
 
@@ -68,7 +68,7 @@ public class XpathRegressionNeedBracesTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionNeedBracesSingleLine']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='test']]/SLIST/LITERAL_IF");
@@ -77,7 +77,7 @@ public class XpathRegressionNeedBracesTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testSingleLineLambda() throws Exception {
+  void singleLineLambda() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionNeedBracesSingleLineLambda.java"));
 
@@ -90,7 +90,7 @@ public class XpathRegressionNeedBracesTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionNeedBracesSingleLineLambda']]"
                 + "/OBJBLOCK/VARIABLE_DEF[./IDENT[@text='r3']]/ASSIGN/LAMBDA");
@@ -99,7 +99,7 @@ public class XpathRegressionNeedBracesTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testEmptyLoopBody() throws Exception {
+  void emptyLoopBody() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionNeedBracesEmptyLoopBody.java"));
 
@@ -110,7 +110,7 @@ public class XpathRegressionNeedBracesTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionNeedBracesEmptyLoopBody']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='test']]/SLIST/LITERAL_WHILE");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNestedForDepthTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNestedForDepthTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.NestedForDepthCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionNestedForDepthTest extends AbstractXpathTestSupport {
+final class XpathRegressionNestedForDepthTest extends AbstractXpathTestSupport {
 
   private final String checkName = NestedForDepthCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionNestedForDepthTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testCorrect() throws Exception {
+  void correct() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionNestedForDepth.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(NestedForDepthCheck.class);
@@ -46,7 +46,7 @@ public class XpathRegressionNestedForDepthTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionNestedForDepth']]/OBJBLOCK"
                 + "/METHOD_DEF[./IDENT[@text='test']]/SLIST/LITERAL_FOR"
@@ -56,7 +56,7 @@ public class XpathRegressionNestedForDepthTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testMax() throws Exception {
+  void max() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionNestedForDepthMax.java"));
 
@@ -68,7 +68,7 @@ public class XpathRegressionNestedForDepthTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionNestedForDepthMax']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='test']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNestedIfDepthTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNestedIfDepthTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.NestedIfDepthCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionNestedIfDepthTest extends AbstractXpathTestSupport {
+final class XpathRegressionNestedIfDepthTest extends AbstractXpathTestSupport {
 
   private final String checkName = NestedIfDepthCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionNestedIfDepthTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testCorrect() throws Exception {
+  void correct() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionNestedIfDepth.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(NestedIfDepthCheck.class);
@@ -46,7 +46,7 @@ public class XpathRegressionNestedIfDepthTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionNestedIfDepth']]/OBJBLOCK"
                 + "/METHOD_DEF[./IDENT[@text='test']]/SLIST/LITERAL_IF"
@@ -56,7 +56,7 @@ public class XpathRegressionNestedIfDepthTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testMax() throws Exception {
+  void max() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionNestedIfDepthMax.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(NestedIfDepthCheck.class);
@@ -67,7 +67,7 @@ public class XpathRegressionNestedIfDepthTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionNestedIfDepthMax']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='test']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNestedTryDepthTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNestedTryDepthTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.NestedTryDepthCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionNestedTryDepthTest extends AbstractXpathTestSupport {
+final class XpathRegressionNestedTryDepthTest extends AbstractXpathTestSupport {
 
   private final String checkName = NestedTryDepthCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionNestedTryDepthTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testCorrect() throws Exception {
+  void correct() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionNestedTryDepth.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(NestedTryDepthCheck.class);
@@ -46,7 +46,7 @@ public class XpathRegressionNestedTryDepthTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionNestedTryDepth']]/OBJBLOCK"
                 + "/METHOD_DEF[./IDENT[@text='test']]/SLIST/LITERAL_TRY/SLIST"
@@ -56,7 +56,7 @@ public class XpathRegressionNestedTryDepthTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testMax() throws Exception {
+  void max() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionNestedTryDepthMax.java"));
 
@@ -68,7 +68,7 @@ public class XpathRegressionNestedTryDepthTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionNestedTryDepthMax']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='test']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNoArrayTrailingCommaTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNoArrayTrailingCommaTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.NoArrayTrailingCommaCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionNoArrayTrailingCommaTest extends AbstractXpathTestSupport {
+final class XpathRegressionNoArrayTrailingCommaTest extends AbstractXpathTestSupport {
 
   private final String checkName = NoArrayTrailingCommaCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionNoArrayTrailingCommaTest extends AbstractXpathTestSu
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionNoArrayTrailingCommaOne.java"));
 
@@ -48,7 +48,7 @@ public class XpathRegressionNoArrayTrailingCommaTest extends AbstractXpathTestSu
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text='SuppressionXpathRegressionNoArrayTrailingCommaOne']]"
                 + "/OBJBLOCK/VARIABLE_DEF[./IDENT[@text='t1']]/ASSIGN/EXPR"
@@ -58,7 +58,7 @@ public class XpathRegressionNoArrayTrailingCommaTest extends AbstractXpathTestSu
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionNoArrayTrailingCommaTwo.java"));
 
@@ -70,7 +70,7 @@ public class XpathRegressionNoArrayTrailingCommaTest extends AbstractXpathTestSu
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionNoArrayTrailingCommaTwo']]"
                 + "/OBJBLOCK/VARIABLE_DEF[./IDENT[@text='t4']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNoCloneTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNoCloneTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionNoCloneTest extends AbstractXpathTestSupport {
+final class XpathRegressionNoCloneTest extends AbstractXpathTestSupport {
 
   private final String checkName = NoCloneCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionNoCloneTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionNoCloneOne.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(NoCloneCheck.class);
@@ -61,7 +61,7 @@ public class XpathRegressionNoCloneTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionNoCloneTwo.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(NoCloneCheck.class);
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNoEnumTrailingCommaTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNoEnumTrailingCommaTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.NoEnumTrailingCommaCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionNoEnumTrailingCommaTest extends AbstractXpathTestSupport {
+final class XpathRegressionNoEnumTrailingCommaTest extends AbstractXpathTestSupport {
 
   private final String checkName = NoEnumTrailingCommaCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionNoEnumTrailingCommaTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionNoEnumTrailingCommaOne.java"));
 
@@ -47,7 +47,7 @@ public class XpathRegressionNoEnumTrailingCommaTest extends AbstractXpathTestSup
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionNoEnumTrailingCommaOne']]"
                 + "/OBJBLOCK/ENUM_DEF[./IDENT[@text='Foo3']]/OBJBLOCK/COMMA[2]");
@@ -56,7 +56,7 @@ public class XpathRegressionNoEnumTrailingCommaTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionNoEnumTrailingCommaTwo.java"));
 
@@ -67,7 +67,7 @@ public class XpathRegressionNoEnumTrailingCommaTest extends AbstractXpathTestSup
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionNoEnumTrailingCommaTwo']]"
                 + "/OBJBLOCK/ENUM_DEF[./IDENT[@text='Foo6']]/OBJBLOCK/COMMA[2]");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNoFinalizerTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNoFinalizerTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionNoFinalizerTest extends AbstractXpathTestSupport {
+final class XpathRegressionNoFinalizerTest extends AbstractXpathTestSupport {
 
   @Override
   protected String getCheckName() {
@@ -34,7 +34,7 @@ public class XpathRegressionNoFinalizerTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionNoFinalizer1.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(NoFinalizerCheck.class);
@@ -59,7 +59,7 @@ public class XpathRegressionNoFinalizerTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionNoFinalizer2.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(NoFinalizerCheck.class);
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNoLineWrapTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNoLineWrapTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionNoLineWrapTest extends AbstractXpathTestSupport {
+final class XpathRegressionNoLineWrapTest extends AbstractXpathTestSupport {
 
   @Override
   protected String getCheckName() {
@@ -34,7 +34,7 @@ public class XpathRegressionNoLineWrapTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionNoLineWrap1.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(NoLineWrapCheck.class);
@@ -50,7 +50,7 @@ public class XpathRegressionNoLineWrapTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionNoLineWrap2.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(NoLineWrapCheck.class);
@@ -78,7 +78,7 @@ public class XpathRegressionNoLineWrapTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionNoLineWrap3.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(NoLineWrapCheck.class);
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNoWhitespaceAfterTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNoWhitespaceAfterTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.NoWhitespaceAfterCheck;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionNoWhitespaceAfterTest extends AbstractXpathTestSupport {
+final class XpathRegressionNoWhitespaceAfterTest extends AbstractXpathTestSupport {
 
   private final String checkName = NoWhitespaceAfterCheck.class.getSimpleName();
 
@@ -37,7 +37,7 @@ public class XpathRegressionNoWhitespaceAfterTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testNoWhitespaceAfter() throws Exception {
+  void noWhitespaceAfter() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionNoWhitespaceAfter.java"));
 
@@ -61,7 +61,7 @@ public class XpathRegressionNoWhitespaceAfterTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testTokens() throws Exception {
+  void tokens() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionNoWhitespaceAfterTokens.java"));
 
@@ -73,7 +73,7 @@ public class XpathRegressionNoWhitespaceAfterTest extends AbstractXpathTestSuppo
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionNoWhitespaceAfterTokens']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='test']]"
@@ -84,7 +84,7 @@ public class XpathRegressionNoWhitespaceAfterTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testAllowLineBreaks() throws Exception {
+  void allowLineBreaks() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionNoWhitespaceAfterLineBreaks.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNoWhitespaceBeforeCaseDefaultColonTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNoWhitespaceBeforeCaseDefaultColonTest.java
@@ -19,15 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.NoWhitespaceBeforeCaseDefaultColonCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionNoWhitespaceBeforeCaseDefaultColonTest
-    extends AbstractXpathTestSupport {
+final class XpathRegressionNoWhitespaceBeforeCaseDefaultColonTest extends AbstractXpathTestSupport {
 
   private final String checkName = NoWhitespaceBeforeCaseDefaultColonCheck.class.getSimpleName();
 
@@ -37,7 +36,7 @@ public class XpathRegressionNoWhitespaceBeforeCaseDefaultColonTest
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionNoWhitespaceBeforeCaseDefaultColonOne.java"));
 
@@ -53,7 +52,7 @@ public class XpathRegressionNoWhitespaceBeforeCaseDefaultColonTest
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT[@text="
                 + "'SuppressionXpathRegressionNoWhitespaceBeforeCaseDefaultColonOne']]"
                 + "/OBJBLOCK/INSTANCE_INIT/SLIST/LITERAL_SWITCH/CASE_GROUP/LITERAL_CASE/COLON");
@@ -62,7 +61,7 @@ public class XpathRegressionNoWhitespaceBeforeCaseDefaultColonTest
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionNoWhitespaceBeforeCaseDefaultColonTwo.java"));
 
@@ -78,7 +77,7 @@ public class XpathRegressionNoWhitespaceBeforeCaseDefaultColonTest
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT[@text="
                 + "'SuppressionXpathRegressionNoWhitespaceBeforeCaseDefaultColonTwo']]"
                 + "/OBJBLOCK/INSTANCE_INIT/SLIST/LITERAL_SWITCH/CASE_GROUP"
@@ -88,7 +87,7 @@ public class XpathRegressionNoWhitespaceBeforeCaseDefaultColonTest
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionNoWhitespaceBeforeCaseDefaultColonThree.java"));
 
@@ -104,7 +103,7 @@ public class XpathRegressionNoWhitespaceBeforeCaseDefaultColonTest
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT[@text="
                 + "'SuppressionXpathRegressionNoWhitespaceBeforeCaseDefaultColonThree']]"
                 + "/OBJBLOCK/INSTANCE_INIT/SLIST/LITERAL_SWITCH/CASE_GROUP"
@@ -114,7 +113,7 @@ public class XpathRegressionNoWhitespaceBeforeCaseDefaultColonTest
   }
 
   @Test
-  public void testFour() throws Exception {
+  void four() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionNoWhitespaceBeforeCaseDefaultColonFour.java"));
 
@@ -130,7 +129,7 @@ public class XpathRegressionNoWhitespaceBeforeCaseDefaultColonTest
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT[@text="
                 + "'SuppressionXpathRegressionNoWhitespaceBeforeCaseDefaultColonFour']]"
                 + "/OBJBLOCK/INSTANCE_INIT/SLIST/LITERAL_SWITCH/CASE_GROUP"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNoWhitespaceBeforeTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionNoWhitespaceBeforeTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.NoWhitespaceBeforeCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionNoWhitespaceBeforeTest extends AbstractXpathTestSupport {
+final class XpathRegressionNoWhitespaceBeforeTest extends AbstractXpathTestSupport {
 
   private final String checkName = NoWhitespaceBeforeCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionNoWhitespaceBeforeTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testNoWhitespaceBefore() throws Exception {
+  void noWhitespaceBefore() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionNoWhitespaceBefore.java"));
 
@@ -48,7 +48,7 @@ public class XpathRegressionNoWhitespaceBeforeTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionNoWhitespaceBefore']]/OBJBLOCK"
                 + "/VARIABLE_DEF[./IDENT[@text='bad']]/SEMI");
@@ -57,7 +57,7 @@ public class XpathRegressionNoWhitespaceBeforeTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testTokens() throws Exception {
+  void tokens() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionNoWhitespaceBeforeTokens.java"));
 
@@ -70,7 +70,7 @@ public class XpathRegressionNoWhitespaceBeforeTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionNoWhitespaceBeforeTokens']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='test']]"
@@ -81,7 +81,7 @@ public class XpathRegressionNoWhitespaceBeforeTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void testAllowLineBreaks() throws Exception {
+  void allowLineBreaks() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionNoWhitespaceBeforeLineBreaks.java"));
 
@@ -94,7 +94,7 @@ public class XpathRegressionNoWhitespaceBeforeTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionNoWhitespaceBeforeLineBreaks']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='test']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionOneStatementPerLineTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionOneStatementPerLineTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.OneStatementPerLineCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionOneStatementPerLineTest extends AbstractXpathTestSupport {
+final class XpathRegressionOneStatementPerLineTest extends AbstractXpathTestSupport {
 
   private final String checkName = OneStatementPerLineCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionOneStatementPerLineTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionOneStatementPerLineOne.java"));
 
@@ -47,7 +47,7 @@ public class XpathRegressionOneStatementPerLineTest extends AbstractXpathTestSup
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionOneStatementPerLineOne']]/OBJBLOCK"
                 + "/VARIABLE_DEF[./IDENT[@text='j']]/SEMI");
@@ -56,7 +56,7 @@ public class XpathRegressionOneStatementPerLineTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionOneStatementPerLineTwo.java"));
 
@@ -67,7 +67,7 @@ public class XpathRegressionOneStatementPerLineTest extends AbstractXpathTestSup
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionOneStatementPerLineTwo']]/OBJBLOCK"
                 + "/METHOD_DEF[./IDENT[@text='foo5']]/SLIST/LITERAL_FOR/SLIST/SEMI[2]");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionOneTopLevelClassTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionOneTopLevelClassTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionOneTopLevelClassTest extends AbstractXpathTestSupport {
+final class XpathRegressionOneTopLevelClassTest extends AbstractXpathTestSupport {
 
   private final String checkName = OneTopLevelClassCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionOneTopLevelClassTest extends AbstractXpathTestSuppor
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionOneTopLevelClassFirst.java"));
 
@@ -58,7 +58,7 @@ public class XpathRegressionOneTopLevelClassTest extends AbstractXpathTestSuppor
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionOneTopLevelClassSecond.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionOperatorWrapTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionOperatorWrapTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.OperatorWrapCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionOperatorWrapTest extends AbstractXpathTestSupport {
+final class XpathRegressionOperatorWrapTest extends AbstractXpathTestSupport {
 
   private final String checkName = OperatorWrapCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionOperatorWrapTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOperatorWrapNewLine() throws Exception {
+  void operatorWrapNewLine() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionOperatorWrapNewLine.java"));
 
@@ -47,7 +47,7 @@ public class XpathRegressionOperatorWrapTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text"
                 + "='SuppressionXpathRegressionOperatorWrapNewLine']]"
@@ -60,7 +60,7 @@ public class XpathRegressionOperatorWrapTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOperatorWrapPreviousLine() throws Exception {
+  void operatorWrapPreviousLine() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionOperatorWrapPreviousLine.java"));
 
@@ -73,7 +73,7 @@ public class XpathRegressionOperatorWrapTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text='SuppressionXpathRegressionOperatorWrapPreviousLine']]"
                 + "/OBJBLOCK/VARIABLE_DEF[./IDENT[@text='b']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionOuterTypeFilenameTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionOuterTypeFilenameTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionOuterTypeFilenameTest extends AbstractXpathTestSupport {
+final class XpathRegressionOuterTypeFilenameTest extends AbstractXpathTestSupport {
 
   private final String checkName = OuterTypeFilenameCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionOuterTypeFilenameTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testNoPublic() throws Exception {
+  void noPublic() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionOuterTypeFilename1.java"));
 
@@ -56,7 +56,7 @@ public class XpathRegressionOuterTypeFilenameTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testNested() throws Exception {
+  void nested() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionOuterTypeFilename2.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionOuterTypeNumberTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionOuterTypeNumberTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionOuterTypeNumberTest extends AbstractXpathTestSupport {
+final class XpathRegressionOuterTypeNumberTest extends AbstractXpathTestSupport {
 
   private final String checkName = OuterTypeNumberCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionOuterTypeNumberTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionOuterTypeNumberDefault.java"));
 
@@ -53,7 +53,7 @@ public class XpathRegressionOuterTypeNumberTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testMax() throws Exception {
+  void max() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionOuterTypeNumber.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(OuterTypeNumberCheck.class);
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionOverloadMethodsDeclarationOrderTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionOverloadMethodsDeclarationOrderTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionOverloadMethodsDeclarationOrderTest extends AbstractXpathTestSupport {
+final class XpathRegressionOverloadMethodsDeclarationOrderTest extends AbstractXpathTestSupport {
 
   private final Class<OverloadMethodsDeclarationOrderCheck> clazz =
       OverloadMethodsDeclarationOrderCheck.class;
@@ -37,7 +37,7 @@ public class XpathRegressionOverloadMethodsDeclarationOrderTest extends Abstract
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionOverloadMethodsDeclarationOrder1.java"));
 
@@ -64,7 +64,7 @@ public class XpathRegressionOverloadMethodsDeclarationOrderTest extends Abstract
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionOverloadMethodsDeclarationOrder2.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionPackageAnnotationTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionPackageAnnotationTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionPackageAnnotationTest extends AbstractXpathTestSupport {
+final class XpathRegressionPackageAnnotationTest extends AbstractXpathTestSupport {
 
   private final String checkName = PackageAnnotationCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionPackageAnnotationTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getNonCompilablePath("SuppressionXpathRegressionPackageAnnotationOne.java"));
 
@@ -53,7 +53,7 @@ public class XpathRegressionPackageAnnotationTest extends AbstractXpathTestSuppo
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getNonCompilablePath("SuppressionXpathRegressionPackageAnnotationTwo.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionPackageDeclarationTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionPackageDeclarationTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionPackageDeclarationTest extends AbstractXpathTestSupport {
+final class XpathRegressionPackageDeclarationTest extends AbstractXpathTestSupport {
 
   private final String checkName = PackageDeclarationCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionPackageDeclarationTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void test1() throws Exception {
+  void test1() throws Exception {
     final File fileToProcess = new File(getNonCompilablePath("SuppressionXpathRegression1.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(PackageDeclarationCheck.class);
@@ -54,7 +54,7 @@ public class XpathRegressionPackageDeclarationTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void test2() throws Exception {
+  void test2() throws Exception {
     final File fileToProcess = new File(getNonCompilablePath("SuppressionXpathRegression2.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(PackageDeclarationCheck.class);
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionPackageNameTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionPackageNameTest.java
@@ -21,14 +21,14 @@ package org.checkstyle.suppressionxpathfilter;
 
 import static com.puppycrawl.tools.checkstyle.checks.naming.PackageNameCheck.MSG_KEY;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.naming.PackageNameCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionPackageNameTest extends AbstractXpathTestSupport {
+final class XpathRegressionPackageNameTest extends AbstractXpathTestSupport {
 
   private final String checkName = PackageNameCheck.class.getSimpleName();
 
@@ -38,7 +38,7 @@ public class XpathRegressionPackageNameTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
 
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionPackageNameOne.java"));
 
@@ -57,7 +57,7 @@ public class XpathRegressionPackageNameTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/PACKAGE_DEF/DOT"
                 + "[./IDENT[@text='packagename']]/DOT"
                 + "[./IDENT[@text='suppressionxpathfilter']]"
@@ -67,7 +67,7 @@ public class XpathRegressionPackageNameTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
 
     final File fileToProcess =
         new File(getNonCompilablePath("SuppressionXpathRegressionPackageName.java"));
@@ -86,7 +86,7 @@ public class XpathRegressionPackageNameTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/PACKAGE_DEF/DOT[./IDENT"
                 + "[@text='PACKAGENAME']]/DOT[./IDENT"
                 + "[@text='suppressionxpathfilter']]"
@@ -96,7 +96,7 @@ public class XpathRegressionPackageNameTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
 
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionPackageNameTwo.java"));
 
@@ -115,7 +115,7 @@ public class XpathRegressionPackageNameTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/PACKAGE_DEF/DOT"
                 + "[./IDENT[@text='packagename']]/DOT"
                 + "[./IDENT[@text='suppressionxpathfilter']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionParameterNameTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionParameterNameTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.naming.AbstractNameCheck;
 import com.puppycrawl.tools.checkstyle.checks.naming.ParameterNameCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionParameterNameTest extends AbstractXpathTestSupport {
+final class XpathRegressionParameterNameTest extends AbstractXpathTestSupport {
 
   private final String checkName = ParameterNameCheck.class.getSimpleName();
 
@@ -37,7 +37,7 @@ public class XpathRegressionParameterNameTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testDefaultPattern() throws Exception {
+  void defaultPattern() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionParameterNameDefaultPattern.java"));
 
@@ -51,7 +51,7 @@ public class XpathRegressionParameterNameTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text"
                 + "='SuppressionXpathRegressionParameterNameDefaultPattern']]"
@@ -61,7 +61,7 @@ public class XpathRegressionParameterNameTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testDifferentPattern() throws Exception {
+  void differentPattern() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionParameterNameDifferentPattern.java"));
 
@@ -76,7 +76,7 @@ public class XpathRegressionParameterNameTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text"
                 + "='SuppressionXpathRegressionParameterNameDifferentPattern']]"
@@ -86,7 +86,7 @@ public class XpathRegressionParameterNameTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testIgnoreOverridden() throws Exception {
+  void ignoreOverridden() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionParameterNameIgnoreOverridden.java"));
 
@@ -101,7 +101,7 @@ public class XpathRegressionParameterNameTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text"
                 + "='SuppressionXpathRegressionParameterNameIgnoreOverridden']]"
@@ -111,7 +111,7 @@ public class XpathRegressionParameterNameTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testAccessModifiers() throws Exception {
+  void accessModifiers() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionParameterNameAccessModifier.java"));
 
@@ -127,7 +127,7 @@ public class XpathRegressionParameterNameTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text"
                 + "='SuppressionXpathRegressionParameterNameAccessModifier']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionParenPadTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionParenPadTest.java
@@ -19,16 +19,16 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.AbstractParenPadCheck;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.PadOption;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.ParenPadCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionParenPadTest extends AbstractXpathTestSupport {
+final class XpathRegressionParenPadTest extends AbstractXpathTestSupport {
 
   private final String checkName = ParenPadCheck.class.getSimpleName();
 
@@ -38,7 +38,7 @@ public class XpathRegressionParenPadTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testLeftFollowed() throws Exception {
+  void leftFollowed() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionParenPadLeftFollowed.java"));
 
@@ -49,7 +49,7 @@ public class XpathRegressionParenPadTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionParenPadLeftFollowed']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='method']]/SLIST/LITERAL_IF/LPAREN");
@@ -58,7 +58,7 @@ public class XpathRegressionParenPadTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testLeftNotFollowed() throws Exception {
+  void leftNotFollowed() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionParenPadLeftNotFollowed.java"));
 
@@ -71,7 +71,7 @@ public class XpathRegressionParenPadTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionParenPadLeftNotFollowed']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='method']]/SLIST/LITERAL_IF/LPAREN");
@@ -80,7 +80,7 @@ public class XpathRegressionParenPadTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testRightPreceded() throws Exception {
+  void rightPreceded() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionParenPadRightPreceded.java"));
 
@@ -91,7 +91,7 @@ public class XpathRegressionParenPadTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionParenPadRightPreceded']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='method']]/SLIST/LITERAL_IF/RPAREN");
@@ -100,7 +100,7 @@ public class XpathRegressionParenPadTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testRightNotPreceded() throws Exception {
+  void rightNotPreceded() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionParenPadRightNotPreceded.java"));
 
@@ -113,7 +113,7 @@ public class XpathRegressionParenPadTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionParenPadRightNotPreceded']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='method']]/SLIST/LITERAL_IF/RPAREN");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionPatternVariableNameTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionPatternVariableNameTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.naming.AbstractNameCheck;
 import com.puppycrawl.tools.checkstyle.checks.naming.PatternVariableNameCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionPatternVariableNameTest extends AbstractXpathTestSupport {
+final class XpathRegressionPatternVariableNameTest extends AbstractXpathTestSupport {
 
   private final String checkName = PatternVariableNameCheck.class.getSimpleName();
 
@@ -37,7 +37,7 @@ public class XpathRegressionPatternVariableNameTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getNonCompilablePath("SuppressionXpathRegressionPatternVariableName1.java"));
 
@@ -54,7 +54,7 @@ public class XpathRegressionPatternVariableNameTest extends AbstractXpathTestSup
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionPatternVariableName1']]"
                 + "/OBJBLOCK/CTOR_DEF[./IDENT[@text='MyClass']]/SLIST/LITERAL_IF/EXPR/"
@@ -65,7 +65,7 @@ public class XpathRegressionPatternVariableNameTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getNonCompilablePath("SuppressionXpathRegressionPatternVariableName2.java"));
 
@@ -84,7 +84,7 @@ public class XpathRegressionPatternVariableNameTest extends AbstractXpathTestSup
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionPatternVariableName2']]"
                 + "/OBJBLOCK/CTOR_DEF[./IDENT[@text='MyClass']]/SLIST/LITERAL_IF/EXPR/"
@@ -95,7 +95,7 @@ public class XpathRegressionPatternVariableNameTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess =
         new File(getNonCompilablePath("SuppressionXpathRegressionPatternVariableName3.java"));
 
@@ -114,7 +114,7 @@ public class XpathRegressionPatternVariableNameTest extends AbstractXpathTestSup
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionPatternVariableName3']]"
                 + "/OBJBLOCK/CTOR_DEF[./IDENT[@text='MyClass']]/SLIST/LITERAL_IF/"
@@ -125,7 +125,7 @@ public class XpathRegressionPatternVariableNameTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testFour() throws Exception {
+  void four() throws Exception {
     final File fileToProcess =
         new File(getNonCompilablePath("SuppressionXpathRegressionPatternVariableName4.java"));
 
@@ -144,7 +144,7 @@ public class XpathRegressionPatternVariableNameTest extends AbstractXpathTestSup
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionPatternVariableName1']]"
                 + "/OBJBLOCK/CTOR_DEF[./IDENT[@text='MyClass']]/SLIST/LITERAL_IF/EXPR/"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionRecordComponentNameTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionRecordComponentNameTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.naming.AbstractNameCheck;
 import com.puppycrawl.tools.checkstyle.checks.naming.RecordComponentNameCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionRecordComponentNameTest extends AbstractXpathTestSupport {
+final class XpathRegressionRecordComponentNameTest extends AbstractXpathTestSupport {
 
   private final String checkName = RecordComponentNameCheck.class.getSimpleName();
 
@@ -37,7 +37,7 @@ public class XpathRegressionRecordComponentNameTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getNonCompilablePath("SuppressionXpathRecordComponentName1.java"));
 
@@ -53,7 +53,7 @@ public class XpathRegressionRecordComponentNameTest extends AbstractXpathTestSup
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/RECORD_DEF[./IDENT[@text='SuppressionXpathRecordComponentName1']]"
                 + "/RECORD_COMPONENTS/RECORD_COMPONENT_DEF/IDENT[@text='_value']");
 
@@ -61,7 +61,7 @@ public class XpathRegressionRecordComponentNameTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getNonCompilablePath("SuppressionXpathRecordComponentName2.java"));
 
@@ -78,7 +78,7 @@ public class XpathRegressionRecordComponentNameTest extends AbstractXpathTestSup
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRecordComponentName2']]/OBJBLOCK"
                 + "/RECORD_DEF[./IDENT[@text='MyRecord']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionRecordComponentNumberTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionRecordComponentNumberTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionRecordComponentNumberTest extends AbstractXpathTestSupport {
+final class XpathRegressionRecordComponentNumberTest extends AbstractXpathTestSupport {
 
   private final String checkName = RecordComponentNumberCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionRecordComponentNumberTest extends AbstractXpathTestS
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getNonCompilablePath("SuppressionXpathRecordComponentNumber1.java"));
 
@@ -60,7 +60,7 @@ public class XpathRegressionRecordComponentNumberTest extends AbstractXpathTestS
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getNonCompilablePath("SuppressionXpathRecordComponentNumber2.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionRecordTypeParameterNameTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionRecordTypeParameterNameTest.java
@@ -27,7 +27,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionRecordTypeParameterNameTest extends AbstractXpathTestSupport {
+final class XpathRegressionRecordTypeParameterNameTest extends AbstractXpathTestSupport {
 
   private final String checkName = RecordTypeParameterNameCheck.class.getSimpleName();
 
@@ -37,7 +37,7 @@ public class XpathRegressionRecordTypeParameterNameTest extends AbstractXpathTes
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getNonCompilablePath("SuppressionXpathRegressionRecordTypeParameterName1.java"));
 
@@ -66,7 +66,7 @@ public class XpathRegressionRecordTypeParameterNameTest extends AbstractXpathTes
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getNonCompilablePath("SuppressionXpathRegressionRecordTypeParameterName2.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionRedundantImportTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionRedundantImportTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionRedundantImportTest extends AbstractXpathTestSupport {
+final class XpathRegressionRedundantImportTest extends AbstractXpathTestSupport {
 
   private final String checkName = RedundantImportCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionRedundantImportTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionRedundantImport1.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(RedundantImportCheck.class);
     final String[] expectedViolation = {
@@ -47,13 +47,13 @@ public class XpathRegressionRedundantImportTest extends AbstractXpathTestSupport
               "org.checkstyle.suppressionxpathfilter"
                   + ".redundantimport.SuppressionXpathRegressionRedundantImport1"),
     };
-    final List<String> expectedXpathQueries = Collections.singletonList("/COMPILATION_UNIT/IMPORT");
+    final List<String> expectedXpathQueries = ImmutableList.of("/COMPILATION_UNIT/IMPORT");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionRedundantImport2.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(RedundantImportCheck.class);
     final String[] expectedViolation = {
@@ -61,13 +61,13 @@ public class XpathRegressionRedundantImportTest extends AbstractXpathTestSupport
           + getCheckMessage(
               RedundantImportCheck.class, RedundantImportCheck.MSG_LANG, "java.lang.String"),
     };
-    final List<String> expectedXpathQueries = Collections.singletonList("/COMPILATION_UNIT/IMPORT");
+    final List<String> expectedXpathQueries = ImmutableList.of("/COMPILATION_UNIT/IMPORT");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionRedundantImport3.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(RedundantImportCheck.class);
     final String[] expectedViolation = {
@@ -79,7 +79,7 @@ public class XpathRegressionRedundantImportTest extends AbstractXpathTestSupport
               "java.util.Scanner"),
     };
     final List<String> expectedXpathQueries =
-        Collections.singletonList("/COMPILATION_UNIT/IMPORT[./DOT/IDENT[@text='Scanner']]");
+        ImmutableList.of("/COMPILATION_UNIT/IMPORT[./DOT/IDENT[@text='Scanner']]");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionRequireThisTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionRequireThisTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.RequireThisCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionRequireThisTest extends AbstractXpathTestSupport {
+final class XpathRegressionRequireThisTest extends AbstractXpathTestSupport {
 
   private final String checkName = RequireThisCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionRequireThisTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionRequireThisOne.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(RequireThisCheck.class);
@@ -47,7 +47,7 @@ public class XpathRegressionRequireThisTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionRequireThisOne']]/OBJBLOCK"
                 + "/METHOD_DEF[./IDENT[@text='changeAge']]/SLIST/EXPR/ASSIGN"
@@ -57,7 +57,7 @@ public class XpathRegressionRequireThisTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionRequireThisTwo.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(RequireThisCheck.class);
@@ -68,7 +68,7 @@ public class XpathRegressionRequireThisTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionRequireThisTwo']]/OBJBLOCK"
                 + "/METHOD_DEF[./IDENT[@text='method2']]/SLIST/EXPR"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionReturnCountTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionReturnCountTest.java
@@ -19,6 +19,7 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.ReturnCountCheck;
 import java.io.File;
@@ -26,7 +27,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionReturnCountTest extends AbstractXpathTestSupport {
+final class XpathRegressionReturnCountTest extends AbstractXpathTestSupport {
 
   @Override
   protected String getCheckName() {
@@ -34,7 +35,7 @@ public class XpathRegressionReturnCountTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionReturnCount1.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(ReturnCountCheck.class);
@@ -62,7 +63,7 @@ public class XpathRegressionReturnCountTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionReturnCount1.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(ReturnCountCheck.class);
@@ -92,7 +93,7 @@ public class XpathRegressionReturnCountTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionReturnCount2.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(ReturnCountCheck.class);
@@ -120,7 +121,7 @@ public class XpathRegressionReturnCountTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testFour() throws Exception {
+  void four() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionReturnCount2.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(ReturnCountCheck.class);
@@ -150,7 +151,7 @@ public class XpathRegressionReturnCountTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testFive() throws Exception {
+  void five() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionReturnCount3.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(ReturnCountCheck.class);
@@ -176,7 +177,7 @@ public class XpathRegressionReturnCountTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testSix() throws Exception {
+  void six() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionReturnCount4.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(ReturnCountCheck.class);
@@ -186,7 +187,7 @@ public class XpathRegressionReturnCountTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        List.of(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionReturnCount4']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='testLambda']]/SLIST"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionRightCurlyTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionRightCurlyTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.blocks.RightCurlyCheck;
 import com.puppycrawl.tools.checkstyle.checks.blocks.RightCurlyOption;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionRightCurlyTest extends AbstractXpathTestSupport {
+final class XpathRegressionRightCurlyTest extends AbstractXpathTestSupport {
 
   private final String checkName = RightCurlyCheck.class.getSimpleName();
 
@@ -37,7 +37,7 @@ public class XpathRegressionRightCurlyTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionRightCurlyOne.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(RightCurlyCheck.class);
@@ -47,7 +47,7 @@ public class XpathRegressionRightCurlyTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionRightCurlyOne']]/OBJBLOCK"
                 + "/METHOD_DEF[./IDENT[@text='test']]/SLIST/LITERAL_IF/SLIST/RCURLY");
@@ -56,7 +56,7 @@ public class XpathRegressionRightCurlyTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionRightCurlyTwo.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(RightCurlyCheck.class);
@@ -68,7 +68,7 @@ public class XpathRegressionRightCurlyTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionRightCurlyTwo']]/OBJBLOCK"
                 + "/METHOD_DEF[./IDENT[@text='fooMethod']]/SLIST/LITERAL_TRY/SLIST/RCURLY");
@@ -77,7 +77,7 @@ public class XpathRegressionRightCurlyTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionRightCurlyThree.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(RightCurlyCheck.class);
@@ -89,7 +89,7 @@ public class XpathRegressionRightCurlyTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionRightCurlyThree']]/OBJBLOCK"
                 + "/METHOD_DEF[./IDENT[@text='sample']]/SLIST/LITERAL_IF/SLIST/RCURLY");
@@ -98,7 +98,7 @@ public class XpathRegressionRightCurlyTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testFour() throws Exception {
+  void four() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionRightCurlyFour.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(RightCurlyCheck.class);
@@ -111,7 +111,7 @@ public class XpathRegressionRightCurlyTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionRightCurlyFour']]/OBJBLOCK"
                 + "/METHOD_DEF[./IDENT[@text='sample']]/SLIST/LITERAL_IF/SLIST/RCURLY");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionSimplifyBooleanReturnTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionSimplifyBooleanReturnTest.java
@@ -21,14 +21,14 @@ package org.checkstyle.suppressionxpathfilter;
 
 import static com.puppycrawl.tools.checkstyle.checks.coding.SimplifyBooleanReturnCheck.MSG_KEY;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.SimplifyBooleanReturnCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionSimplifyBooleanReturnTest extends AbstractXpathTestSupport {
+final class XpathRegressionSimplifyBooleanReturnTest extends AbstractXpathTestSupport {
 
   private static final Class<SimplifyBooleanReturnCheck> CLASS = SimplifyBooleanReturnCheck.class;
   private final String checkName = CLASS.getSimpleName();
@@ -39,7 +39,7 @@ public class XpathRegressionSimplifyBooleanReturnTest extends AbstractXpathTestS
   }
 
   @Test
-  public void testIfBooleanEqualsBoolean() throws Exception {
+  void ifBooleanEqualsBoolean() throws Exception {
     final File fileToProcess =
         new File(
             getPath("SuppressionXpathRegressionSimplifyBooleanReturnIfBooleanEqualsBoolean.java"));
@@ -51,7 +51,7 @@ public class XpathRegressionSimplifyBooleanReturnTest extends AbstractXpathTestS
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT[@text="
                 + "'SuppressionXpathRegressionSimplifyBooleanReturnIfBooleanEqualsBoolean']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='toTest']]/SLIST/LITERAL_IF");
@@ -60,7 +60,7 @@ public class XpathRegressionSimplifyBooleanReturnTest extends AbstractXpathTestS
   }
 
   @Test
-  public void testIfBooleanReturnBoolean() throws Exception {
+  void ifBooleanReturnBoolean() throws Exception {
     final File fileToProcess =
         new File(
             getPath("SuppressionXpathRegressionSimplifyBooleanReturnIfBooleanReturnBoolean.java"));
@@ -72,7 +72,7 @@ public class XpathRegressionSimplifyBooleanReturnTest extends AbstractXpathTestS
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT[@text="
                 + "'SuppressionXpathRegressionSimplifyBooleanReturnIfBooleanReturnBoolean']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='toTest']]/SLIST/EXPR/METHOD_CALL/ELIST"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionSingleSpaceSeparatorTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionSingleSpaceSeparatorTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.SingleSpaceSeparatorCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionSingleSpaceSeparatorTest extends AbstractXpathTestSupport {
+final class XpathRegressionSingleSpaceSeparatorTest extends AbstractXpathTestSupport {
 
   private final String checkName = SingleSpaceSeparatorCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionSingleSpaceSeparatorTest extends AbstractXpathTestSu
   }
 
   @Test
-  public void testSingleSpaceSeparator() throws Exception {
+  void singleSpaceSeparator() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionSingleSpaceSeparator.java"));
 
@@ -48,7 +48,7 @@ public class XpathRegressionSingleSpaceSeparatorTest extends AbstractXpathTestSu
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionSingleSpaceSeparator']]/OBJBLOCK"
                 + "/VARIABLE_DEF/IDENT[@text='bad']");
@@ -57,7 +57,7 @@ public class XpathRegressionSingleSpaceSeparatorTest extends AbstractXpathTestSu
   }
 
   @Test
-  public void testValidateComments() throws Exception {
+  void validateComments() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionSingleSpaceSeparatorValidateComments.java"));
 
@@ -70,7 +70,7 @@ public class XpathRegressionSingleSpaceSeparatorTest extends AbstractXpathTestSu
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[."
                 + "/IDENT[@text='SuppressionXpathRegressionSingleSpaceSeparatorValidateComments']]"
                 + "/OBJBLOCK/SINGLE_LINE_COMMENT[./COMMENT_CONTENT"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionStaticVariableNameTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionStaticVariableNameTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.naming.AbstractNameCheck;
 import com.puppycrawl.tools.checkstyle.checks.naming.StaticVariableNameCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionStaticVariableNameTest extends AbstractXpathTestSupport {
+final class XpathRegressionStaticVariableNameTest extends AbstractXpathTestSupport {
 
   private final String checkName = StaticVariableNameCheck.class.getSimpleName();
 
@@ -37,7 +37,7 @@ public class XpathRegressionStaticVariableNameTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void test1() throws Exception {
+  void test1() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionStaticVariableName1.java"));
 
@@ -54,7 +54,7 @@ public class XpathRegressionStaticVariableNameTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text"
                 + "='SuppressionXpathRegressionStaticVariableName1']]"
@@ -63,7 +63,7 @@ public class XpathRegressionStaticVariableNameTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void test2() throws Exception {
+  void test2() throws Exception {
     final File fileToProcess =
         new File(getNonCompilablePath("SuppressionXpathRegressionStaticVariableName2.java"));
 
@@ -80,7 +80,7 @@ public class XpathRegressionStaticVariableNameTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text"
                 + "='SuppressionXpathRegressionStaticVariableName2']]"
@@ -91,7 +91,7 @@ public class XpathRegressionStaticVariableNameTest extends AbstractXpathTestSupp
   }
 
   @Test
-  public void test3() throws Exception {
+  void test3() throws Exception {
     final File fileToProcess =
         new File(getNonCompilablePath("SuppressionXpathRegressionStaticVariableName3.java"));
 
@@ -108,7 +108,7 @@ public class XpathRegressionStaticVariableNameTest extends AbstractXpathTestSupp
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text"
                 + "='SuppressionXpathRegressionStaticVariableName2']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionStringLiteralEqualityTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionStringLiteralEqualityTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.StringLiteralEqualityCheck;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionStringLiteralEqualityTest extends AbstractXpathTestSupport {
+final class XpathRegressionStringLiteralEqualityTest extends AbstractXpathTestSupport {
 
   private final String checkName = StringLiteralEqualityCheck.class.getSimpleName();
 
@@ -37,7 +37,7 @@ public class XpathRegressionStringLiteralEqualityTest extends AbstractXpathTestS
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionStringLiteralEquality.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(StringLiteralEqualityCheck.class);
@@ -61,7 +61,7 @@ public class XpathRegressionStringLiteralEqualityTest extends AbstractXpathTestS
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionStringLiteralEquality1.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(StringLiteralEqualityCheck.class);
@@ -85,7 +85,7 @@ public class XpathRegressionStringLiteralEqualityTest extends AbstractXpathTestS
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionStringLiteralEquality2.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(StringLiteralEqualityCheck.class);
@@ -95,7 +95,7 @@ public class XpathRegressionStringLiteralEqualityTest extends AbstractXpathTestS
               StringLiteralEqualityCheck.class, StringLiteralEqualityCheck.MSG_KEY, "=="),
     };
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text='SuppressionXpathRegressionStringLiteralEquality2']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='myFunction']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionSuperCloneTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionSuperCloneTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.AbstractSuperCheck;
 import com.puppycrawl.tools.checkstyle.checks.coding.SuperCloneCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionSuperCloneTest extends AbstractXpathTestSupport {
+final class XpathRegressionSuperCloneTest extends AbstractXpathTestSupport {
 
   @Override
   protected String getCheckName() {
@@ -35,7 +35,7 @@ public class XpathRegressionSuperCloneTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testInnerClone() throws Exception {
+  void innerClone() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionSuperCloneInnerClone.java"));
 
@@ -46,7 +46,7 @@ public class XpathRegressionSuperCloneTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpath"
                 + "RegressionSuperCloneInnerClone']]"
@@ -57,7 +57,7 @@ public class XpathRegressionSuperCloneTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testNoSuperClone() throws Exception {
+  void noSuperClone() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionSuperCloneNoSuperClone.java"));
 
@@ -68,7 +68,7 @@ public class XpathRegressionSuperCloneTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpath"
                 + "RegressionSuperCloneNoSuperClone']]"
@@ -79,7 +79,7 @@ public class XpathRegressionSuperCloneTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testPlainAndSubclasses() throws Exception {
+  void plainAndSubclasses() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionSuperClonePlainAndSubclasses.java"));
 
@@ -90,7 +90,7 @@ public class XpathRegressionSuperCloneTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpath"
                 + "RegressionSuperClonePlainAndSubclasses']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionThrowsCountTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionThrowsCountTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.design.ThrowsCountCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionThrowsCountTest extends AbstractXpathTestSupport {
+final class XpathRegressionThrowsCountTest extends AbstractXpathTestSupport {
 
   private final String checkName = ThrowsCountCheck.class.getSimpleName();
 
@@ -36,14 +36,14 @@ public class XpathRegressionThrowsCountTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionThrowsCount1.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(ThrowsCountCheck.class);
     final String[] expectedViolation = {
       "4:30: " + getCheckMessage(ThrowsCountCheck.class, ThrowsCountCheck.MSG_KEY, 5, 4),
     };
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text='SuppressionXpathRegressionThrowsCount1']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='myFunction']]"
@@ -53,7 +53,7 @@ public class XpathRegressionThrowsCountTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionThrowsCount2.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(ThrowsCountCheck.class);
 
@@ -63,7 +63,7 @@ public class XpathRegressionThrowsCountTest extends AbstractXpathTestSupport {
       "4:30: " + getCheckMessage(ThrowsCountCheck.class, ThrowsCountCheck.MSG_KEY, 3, 2),
     };
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/INTERFACE_DEF[./IDENT[@text='SuppressionXpathRegressionThrowsCount2']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='myFunction']]"
@@ -73,7 +73,7 @@ public class XpathRegressionThrowsCountTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionThrowsCount3.java"));
     final DefaultConfiguration moduleConfig = createModuleConfig(ThrowsCountCheck.class);
 
@@ -83,7 +83,7 @@ public class XpathRegressionThrowsCountTest extends AbstractXpathTestSupport {
       "9:40: " + getCheckMessage(ThrowsCountCheck.class, ThrowsCountCheck.MSG_KEY, 5, 4),
     };
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text='SuppressionXpathRegressionThrowsCount3']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='myFunc']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionTodoCommentTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionTodoCommentTest.java
@@ -21,14 +21,14 @@ package org.checkstyle.suppressionxpathfilter;
 
 import static com.puppycrawl.tools.checkstyle.checks.TodoCommentCheck.MSG_KEY;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.TodoCommentCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionTodoCommentTest extends AbstractXpathTestSupport {
+final class XpathRegressionTodoCommentTest extends AbstractXpathTestSupport {
   private final String checkName = TodoCommentCheck.class.getSimpleName();
 
   @Override
@@ -37,7 +37,7 @@ public class XpathRegressionTodoCommentTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionTodoCommentOne.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(TodoCommentCheck.class);
@@ -48,7 +48,7 @@ public class XpathRegressionTodoCommentTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT[@text="
                 + "'SuppressionXpathRegressionTodoCommentOne']]/OBJBLOCK/"
                 + "SINGLE_LINE_COMMENT/COMMENT_CONTENT[@text=' warn FIXME:\\n']");
@@ -57,7 +57,7 @@ public class XpathRegressionTodoCommentTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionTodoCommentTwo.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(TodoCommentCheck.class);
@@ -68,7 +68,7 @@ public class XpathRegressionTodoCommentTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT[@text="
                 + "'SuppressionXpathRegressionTodoCommentTwo']]/"
                 + "OBJBLOCK/BLOCK_COMMENT_BEGIN/COMMENT_CONTENT"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionTrailingCommentTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionTrailingCommentTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.TrailingCommentCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionTrailingCommentTest extends AbstractXpathTestSupport {
+final class XpathRegressionTrailingCommentTest extends AbstractXpathTestSupport {
   private final String checkName = TrailingCommentCheck.class.getSimpleName();
 
   @Override
@@ -35,7 +35,7 @@ public class XpathRegressionTrailingCommentTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionTrailingComment1.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(TrailingCommentCheck.class);
@@ -45,7 +45,7 @@ public class XpathRegressionTrailingCommentTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionTrailingComment1']]/"
                 + "OBJBLOCK/SINGLE_LINE_COMMENT[./COMMENT_CONTENT[@text=' don&apos;"
@@ -55,7 +55,7 @@ public class XpathRegressionTrailingCommentTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionTrailingComment2.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(TrailingCommentCheck.class);
@@ -65,7 +65,7 @@ public class XpathRegressionTrailingCommentTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionTrailingComment2']]"
                 + "/OBJBLOCK/SINGLE_LINE_COMMENT[./COMMENT_CONTENT[@text=' warn\\n']]");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionTypeNameTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionTypeNameTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.naming.AbstractNameCheck;
 import com.puppycrawl.tools.checkstyle.checks.naming.TypeNameCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionTypeNameTest extends AbstractXpathTestSupport {
+final class XpathRegressionTypeNameTest extends AbstractXpathTestSupport {
 
   private final String checkName = TypeNameCheck.class.getSimpleName();
 
@@ -37,7 +37,7 @@ public class XpathRegressionTypeNameTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void test1() throws Exception {
+  void test1() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionTypeName1.java"));
 
     final String pattern = "^[A-Z][a-zA-Z0-9]*$";
@@ -50,7 +50,7 @@ public class XpathRegressionTypeNameTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text"
                 + "='SuppressionXpathRegressionTypeName1']]"
@@ -59,7 +59,7 @@ public class XpathRegressionTypeNameTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void test2() throws Exception {
+  void test2() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionTypeName2.java"));
 
     final String pattern = "^I_[a-zA-Z0-9]*$";
@@ -74,7 +74,7 @@ public class XpathRegressionTypeNameTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT"
                 + "/CLASS_DEF[./IDENT[@text"
                 + "='SuppressionXpathRegressionTypeName2']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionTypecastParenPadTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionTypecastParenPadTest.java
@@ -19,17 +19,17 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.AbstractParenPadCheck;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.PadOption;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.TypecastParenPadCheck;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionTypecastParenPadTest extends AbstractXpathTestSupport {
+final class XpathRegressionTypecastParenPadTest extends AbstractXpathTestSupport {
 
   private final String checkName = TypecastParenPadCheck.class.getSimpleName();
 
@@ -39,7 +39,7 @@ public class XpathRegressionTypecastParenPadTest extends AbstractXpathTestSuppor
   }
 
   @Test
-  public void testLeftFollowed() throws Exception {
+  void leftFollowed() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionTypecastParenPadLeftFollowed.java"));
 
@@ -64,7 +64,7 @@ public class XpathRegressionTypecastParenPadTest extends AbstractXpathTestSuppor
   }
 
   @Test
-  public void testLeftNotFollowed() throws Exception {
+  void leftNotFollowed() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionTypecastParenPadLeftNotFollowed.java"));
 
@@ -90,7 +90,7 @@ public class XpathRegressionTypecastParenPadTest extends AbstractXpathTestSuppor
   }
 
   @Test
-  public void testRightPreceded() throws Exception {
+  void rightPreceded() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionTypecastParenPadRightPreceded.java"));
 
@@ -103,7 +103,7 @@ public class XpathRegressionTypecastParenPadTest extends AbstractXpathTestSuppor
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionTypecastParenPadRightPreceded']]"
                 + "/OBJBLOCK/VARIABLE_DEF[./IDENT[@text='bad']]/ASSIGN/EXPR/TYPECAST/RPAREN");
@@ -112,7 +112,7 @@ public class XpathRegressionTypecastParenPadTest extends AbstractXpathTestSuppor
   }
 
   @Test
-  public void testRightNotPreceded() throws Exception {
+  void rightNotPreceded() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionTypecastParenPadRightNotPreceded.java"));
 
@@ -126,7 +126,7 @@ public class XpathRegressionTypecastParenPadTest extends AbstractXpathTestSuppor
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT["
                 + "@text='SuppressionXpathRegressionTypecastParenPadRightNotPreceded']]"
                 + "/OBJBLOCK/VARIABLE_DEF[./IDENT[@text='bad']]/ASSIGN/EXPR/TYPECAST/RPAREN");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionUncommentedMainTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionUncommentedMainTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionUncommentedMainTest extends AbstractXpathTestSupport {
+final class XpathRegressionUncommentedMainTest extends AbstractXpathTestSupport {
 
   private final Class<UncommentedMainCheck> clazz = UncommentedMainCheck.class;
 
@@ -36,7 +36,7 @@ public class XpathRegressionUncommentedMainTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionUncommentedMain.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(UncommentedMainCheck.class);
@@ -61,7 +61,7 @@ public class XpathRegressionUncommentedMainTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionUncommentedMainTwo.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionUnnecessaryParenthesesTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionUnnecessaryParenthesesTest.java
@@ -19,15 +19,15 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.UnnecessaryParenthesesCheck;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionUnnecessaryParenthesesTest extends AbstractXpathTestSupport {
+final class XpathRegressionUnnecessaryParenthesesTest extends AbstractXpathTestSupport {
 
   @Override
   protected String getCheckName() {
@@ -35,7 +35,7 @@ public class XpathRegressionUnnecessaryParenthesesTest extends AbstractXpathTest
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionUnnecessaryParentheses1.java"));
 
@@ -62,7 +62,7 @@ public class XpathRegressionUnnecessaryParenthesesTest extends AbstractXpathTest
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionUnnecessaryParentheses2.java"));
 
@@ -89,7 +89,7 @@ public class XpathRegressionUnnecessaryParenthesesTest extends AbstractXpathTest
   }
 
   @Test
-  public void testThree() throws Exception {
+  void three() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionUnnecessaryParentheses3.java"));
 
@@ -102,7 +102,7 @@ public class XpathRegressionUnnecessaryParenthesesTest extends AbstractXpathTest
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionUnnecessaryParentheses3']]"
                 + "/OBJBLOCK/VARIABLE_DEF[./IDENT[@text='predicate']]"
@@ -112,7 +112,7 @@ public class XpathRegressionUnnecessaryParenthesesTest extends AbstractXpathTest
   }
 
   @Test
-  public void testFour() throws Exception {
+  void four() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionUnnecessaryParentheses4.java"));
 
@@ -125,7 +125,7 @@ public class XpathRegressionUnnecessaryParenthesesTest extends AbstractXpathTest
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionUnnecessaryParentheses4']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='foo']]"
@@ -136,7 +136,7 @@ public class XpathRegressionUnnecessaryParenthesesTest extends AbstractXpathTest
   }
 
   @Test
-  public void testFive() throws Exception {
+  void five() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionUnnecessaryParentheses5.java"));
 
@@ -151,7 +151,7 @@ public class XpathRegressionUnnecessaryParenthesesTest extends AbstractXpathTest
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionUnnecessaryParentheses5']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='foo']]"
@@ -162,7 +162,7 @@ public class XpathRegressionUnnecessaryParenthesesTest extends AbstractXpathTest
   }
 
   @Test
-  public void testSix() throws Exception {
+  void six() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionUnnecessaryParentheses6.java"));
 
@@ -175,7 +175,7 @@ public class XpathRegressionUnnecessaryParenthesesTest extends AbstractXpathTest
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='SuppressionXpathRegressionUnnecessaryParentheses6']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='foo']]"
@@ -186,7 +186,7 @@ public class XpathRegressionUnnecessaryParenthesesTest extends AbstractXpathTest
   }
 
   @Test
-  public void testSeven() throws Exception {
+  void seven() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionUnnecessaryParentheses7.java"));
 
@@ -213,7 +213,7 @@ public class XpathRegressionUnnecessaryParenthesesTest extends AbstractXpathTest
   }
 
   @Test
-  public void testEight() throws Exception {
+  void eight() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionUnnecessaryParentheses8.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionUnnecessarySemicolonAfterOuterTypeDeclarationTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionUnnecessarySemicolonAfterOuterTypeDeclarationTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.UnnecessarySemicolonAfterOuterTypeDeclarationCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionUnnecessarySemicolonAfterOuterTypeDeclarationTest
+final class XpathRegressionUnnecessarySemicolonAfterOuterTypeDeclarationTest
     extends AbstractXpathTestSupport {
 
   private static final Class<UnnecessarySemicolonAfterOuterTypeDeclarationCheck> CLASS =
@@ -38,7 +38,7 @@ public class XpathRegressionUnnecessarySemicolonAfterOuterTypeDeclarationTest
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(
             getPath(
@@ -48,13 +48,13 @@ public class XpathRegressionUnnecessarySemicolonAfterOuterTypeDeclarationTest
       "5:2: " + getCheckMessage(CLASS, UnnecessarySemicolonAfterOuterTypeDeclarationCheck.MSG_SEMI),
     };
 
-    final List<String> expectedXpathQueries = Collections.singletonList("/COMPILATION_UNIT/SEMI");
+    final List<String> expectedXpathQueries = ImmutableList.of("/COMPILATION_UNIT/SEMI");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(
             getPath(
@@ -66,7 +66,7 @@ public class XpathRegressionUnnecessarySemicolonAfterOuterTypeDeclarationTest
           + getCheckMessage(CLASS, UnnecessarySemicolonAfterOuterTypeDeclarationCheck.MSG_SEMI),
     };
 
-    final List<String> expectedXpathQueries = Collections.singletonList("/COMPILATION_UNIT/SEMI");
+    final List<String> expectedXpathQueries = ImmutableList.of("/COMPILATION_UNIT/SEMI");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionUnnecessarySemicolonAfterTypeMemberDeclarationTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionUnnecessarySemicolonAfterTypeMemberDeclarationTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.UnnecessarySemicolonAfterTypeMemberDeclarationCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionUnnecessarySemicolonAfterTypeMemberDeclarationTest
+final class XpathRegressionUnnecessarySemicolonAfterTypeMemberDeclarationTest
     extends AbstractXpathTestSupport {
 
   private static final Class<UnnecessarySemicolonAfterTypeMemberDeclarationCheck> CLASS =
@@ -38,7 +38,7 @@ public class XpathRegressionUnnecessarySemicolonAfterTypeMemberDeclarationTest
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final File fileToProcess =
         new File(
             getPath(
@@ -50,7 +50,7 @@ public class XpathRegressionUnnecessarySemicolonAfterTypeMemberDeclarationTest
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT"
                 + "[@text="
                 + "'SuppressionXpathRegressionUnnecessarySemicolonAfterTypeMemberDeclaration']]"
@@ -60,7 +60,7 @@ public class XpathRegressionUnnecessarySemicolonAfterTypeMemberDeclarationTest
   }
 
   @Test
-  public void testTokens() throws Exception {
+  void tokens() throws Exception {
     final File fileToProcess =
         new File(
             getPath(
@@ -75,7 +75,7 @@ public class XpathRegressionUnnecessarySemicolonAfterTypeMemberDeclarationTest
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[."
                 + "/IDENT[@text='SuppressionXpathRegressionUnnecessarySemicolonAfterTypeMember"
                 + "DeclarationTokens']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionUnnecessarySemicolonInEnumerationTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionUnnecessarySemicolonInEnumerationTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.UnnecessarySemicolonInEnumerationCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionUnnecessarySemicolonInEnumerationTest extends AbstractXpathTestSupport {
+final class XpathRegressionUnnecessarySemicolonInEnumerationTest extends AbstractXpathTestSupport {
 
   private final String checkName = UnnecessarySemicolonInEnumerationCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionUnnecessarySemicolonInEnumerationTest extends Abstra
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionUnnecessarySemicolonInEnumeration.java"));
 
@@ -51,13 +51,13 @@ public class XpathRegressionUnnecessarySemicolonInEnumerationTest extends Abstra
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList("/COMPILATION_UNIT/ENUM_DEF[./IDENT[@text='Bad']]/OBJBLOCK/SEMI");
+        ImmutableList.of("/COMPILATION_UNIT/ENUM_DEF[./IDENT[@text='Bad']]/OBJBLOCK/SEMI");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionUnnecessarySemicolonInEnumerationAll.java"));
 
@@ -72,7 +72,7 @@ public class XpathRegressionUnnecessarySemicolonInEnumerationTest extends Abstra
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/ENUM_DEF[./IDENT[@text="
                 + "'SuppressionXpathRegressionUnnecessarySemicolonInEnumerationAll']]"
                 + "/OBJBLOCK/SEMI");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionUnnecessarySemicolonInTryWithResourcesTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionUnnecessarySemicolonInTryWithResourcesTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.coding.UnnecessarySemicolonInTryWithResourcesCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionUnnecessarySemicolonInTryWithResourcesTest
+final class XpathRegressionUnnecessarySemicolonInTryWithResourcesTest
     extends AbstractXpathTestSupport {
 
   private final String checkName =
@@ -38,7 +38,7 @@ public class XpathRegressionUnnecessarySemicolonInTryWithResourcesTest
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionUnnecessarySemicolonInTryWithResources.java"));
     final DefaultConfiguration moduleConfig =
@@ -54,7 +54,7 @@ public class XpathRegressionUnnecessarySemicolonInTryWithResourcesTest
               UnnecessarySemicolonInTryWithResourcesCheck.MSG_SEMI),
     };
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT[@text="
                 + "'SuppressionXpathRegressionUnnecessarySemicolonInTryWithResources']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='m']]/SLIST/LITERAL_TRY"
@@ -63,7 +63,7 @@ public class XpathRegressionUnnecessarySemicolonInTryWithResourcesTest
   }
 
   @Test
-  public void testAllowWhenNoBraceAfterSemicolon() throws Exception {
+  void allowWhenNoBraceAfterSemicolon() throws Exception {
     final File fileToProcess =
         new File(
             getPath(
@@ -81,7 +81,7 @@ public class XpathRegressionUnnecessarySemicolonInTryWithResourcesTest
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT[@text="
                 + "'SuppressionXpathRegressionUnnecessarySemicolonInTryWithResourcesNoBrace']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='test']]"
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionUnusedImportsTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionUnusedImportsTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.imports.UnusedImportsCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionUnusedImportsTest extends AbstractXpathTestSupport {
+final class XpathRegressionUnusedImportsTest extends AbstractXpathTestSupport {
 
   private final String checkName = UnusedImportsCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionUnusedImportsTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionUnusedImportsOne.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(UnusedImportsCheck.class);
@@ -47,14 +47,14 @@ public class XpathRegressionUnusedImportsTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/IMPORT/DOT[./IDENT[@text='List']]/DOT/IDENT[@text='java']");
 
     runVerifications(moduleConfig, fileToProcess, expectedViolation, expectedXpathQueries);
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionUnusedImportsTwo.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(UnusedImportsCheck.class);
@@ -66,7 +66,7 @@ public class XpathRegressionUnusedImportsTest extends AbstractXpathTestSupport {
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/STATIC_IMPORT/DOT"
                 + "[./IDENT[@text='Entry']]/DOT[./IDENT[@text='Map']]"
                 + "/DOT/IDENT[@text='java']");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionUnusedLocalVariableTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionUnusedLocalVariableTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionUnusedLocalVariableTest extends AbstractXpathTestSupport {
+final class XpathRegressionUnusedLocalVariableTest extends AbstractXpathTestSupport {
   private final String checkName = UnusedLocalVariableCheck.class.getSimpleName();
 
   @Override
@@ -35,7 +35,7 @@ public class XpathRegressionUnusedLocalVariableTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionUnusedLocalVariableOne.java"));
 
@@ -71,7 +71,7 @@ public class XpathRegressionUnusedLocalVariableTest extends AbstractXpathTestSup
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionUnusedLocalVariableTwo.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionUpperEllTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionUpperEllTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionUpperEllTest extends AbstractXpathTestSupport {
+final class XpathRegressionUpperEllTest extends AbstractXpathTestSupport {
 
   private final String checkName = UpperEllCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionUpperEllTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testUpperEllOne() throws Exception {
+  void upperEllOne() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionUpperEllFirst.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(UpperEllCheck.class);
@@ -59,7 +59,7 @@ public class XpathRegressionUpperEllTest extends AbstractXpathTestSupport {
   }
 
   @Test
-  public void testUpperEllTwo() throws Exception {
+  void upperEllTwo() throws Exception {
     final File fileToProcess = new File(getPath("SuppressionXpathRegressionUpperEllSecond.java"));
 
     final DefaultConfiguration moduleConfig = createModuleConfig(UpperEllCheck.class);
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionVariableDeclarationUsageDistanceTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionVariableDeclarationUsageDistanceTest.java
@@ -26,7 +26,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionVariableDeclarationUsageDistanceTest extends AbstractXpathTestSupport {
+final class XpathRegressionVariableDeclarationUsageDistanceTest extends AbstractXpathTestSupport {
   private final String checkName = VariableDeclarationUsageDistanceCheck.class.getSimpleName();
 
   @Override
@@ -35,7 +35,7 @@ public class XpathRegressionVariableDeclarationUsageDistanceTest extends Abstrac
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionVariableDeclarationUsageDistance1.java"));
 
@@ -79,7 +79,7 @@ public class XpathRegressionVariableDeclarationUsageDistanceTest extends Abstrac
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionVariableDeclarationUsageDistance2.java"));
 
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionWhitespaceAfterTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionWhitespaceAfterTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.WhitespaceAfterCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionWhitespaceAfterTest extends AbstractXpathTestSupport {
+final class XpathRegressionWhitespaceAfterTest extends AbstractXpathTestSupport {
 
   private final String checkName = WhitespaceAfterCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionWhitespaceAfterTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testWhitespaceAfterTypecast() throws Exception {
+  void whitespaceAfterTypecast() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionWhitespaceAfterTypecast.java"));
 
@@ -48,7 +48,7 @@ public class XpathRegressionWhitespaceAfterTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT["
                 + "@text='SuppressionXpathRegressionWhitespaceAfterTypecast']]/OBJBLOCK"
                 + "/VARIABLE_DEF[./IDENT[@text='bad']]/ASSIGN/EXPR/TYPECAST/RPAREN");
@@ -57,7 +57,7 @@ public class XpathRegressionWhitespaceAfterTest extends AbstractXpathTestSupport
   }
 
   @Test
-  public void testWhitespaceAfterNotFollowed() throws Exception {
+  void whitespaceAfterNotFollowed() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionWhitespaceAfterNotFollowed.java"));
 
@@ -70,7 +70,7 @@ public class XpathRegressionWhitespaceAfterTest extends AbstractXpathTestSupport
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT["
                 + "@text='SuppressionXpathRegressionWhitespaceAfterNotFollowed']]/OBJBLOCK"
                 + "/VARIABLE_DEF[./IDENT[@text='bad']]/ASSIGN/ARRAY_INIT/COMMA");
--- a/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionWhitespaceAroundTest.java
+++ b/src/it/java/org/checkstyle/suppressionxpathfilter/XpathRegressionWhitespaceAroundTest.java
@@ -19,14 +19,14 @@
 
 package org.checkstyle.suppressionxpathfilter;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.WhitespaceAroundCheck;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionWhitespaceAroundTest extends AbstractXpathTestSupport {
+final class XpathRegressionWhitespaceAroundTest extends AbstractXpathTestSupport {
 
   private final String checkName = WhitespaceAroundCheck.class.getSimpleName();
 
@@ -36,7 +36,7 @@ public class XpathRegressionWhitespaceAroundTest extends AbstractXpathTestSuppor
   }
 
   @Test
-  public void testWhitespaceAroundNotPreceded() throws Exception {
+  void whitespaceAroundNotPreceded() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionWhitespaceAroundNotPreceded.java"));
 
@@ -49,7 +49,7 @@ public class XpathRegressionWhitespaceAroundTest extends AbstractXpathTestSuppor
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT["
                 + "@text='SuppressionXpathRegressionWhitespaceAroundNotPreceded']]/OBJBLOCK"
                 + "/VARIABLE_DEF[./IDENT[@text='bad']]/ASSIGN");
@@ -58,7 +58,7 @@ public class XpathRegressionWhitespaceAroundTest extends AbstractXpathTestSuppor
   }
 
   @Test
-  public void testWhitespaceAroundNotFollowed() throws Exception {
+  void whitespaceAroundNotFollowed() throws Exception {
     final File fileToProcess =
         new File(getPath("SuppressionXpathRegressionWhitespaceAroundNotFollowed.java"));
 
@@ -71,7 +71,7 @@ public class XpathRegressionWhitespaceAroundTest extends AbstractXpathTestSuppor
     };
 
     final List<String> expectedXpathQueries =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT["
                 + "@text='SuppressionXpathRegressionWhitespaceAroundNotFollowed']]/OBJBLOCK"
                 + "/VARIABLE_DEF[./IDENT[@text='bad']]/ASSIGN");
--- a/src/main/java/com/puppycrawl/tools/checkstyle/AbstractAutomaticBean.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/AbstractAutomaticBean.java
@@ -275,8 +275,8 @@ public abstract class AbstractAutomaticBean implements Configurable, Contextuali
   /** A converter that converts a string to a pattern. */
   private static final class PatternConverter implements Converter {
 
-    @SuppressWarnings("unchecked")
     @Override
+    @SuppressWarnings("unchecked")
     public Object convert(Class type, Object value) {
       return CommonUtil.createPattern(value.toString());
     }
@@ -285,8 +285,8 @@ public abstract class AbstractAutomaticBean implements Configurable, Contextuali
   /** A converter that converts strings to severity level. */
   private static final class SeverityLevelConverter implements Converter {
 
-    @SuppressWarnings("unchecked")
     @Override
+    @SuppressWarnings("unchecked")
     public Object convert(Class type, Object value) {
       return SeverityLevel.getInstance(value.toString());
     }
@@ -295,8 +295,8 @@ public abstract class AbstractAutomaticBean implements Configurable, Contextuali
   /** A converter that converts strings to scope. */
   private static final class ScopeConverter implements Converter {
 
-    @SuppressWarnings("unchecked")
     @Override
+    @SuppressWarnings("unchecked")
     public Object convert(Class type, Object value) {
       return Scope.getInstance(value.toString());
     }
@@ -305,8 +305,8 @@ public abstract class AbstractAutomaticBean implements Configurable, Contextuali
   /** A converter that converts strings to uri. */
   private static final class UriConverter implements Converter {
 
-    @SuppressWarnings("unchecked")
     @Override
+    @SuppressWarnings("unchecked")
     public Object convert(Class type, Object value) {
       final String url = value.toString();
       URI result = null;
@@ -329,8 +329,8 @@ public abstract class AbstractAutomaticBean implements Configurable, Contextuali
    */
   private static final class RelaxedStringArrayConverter implements Converter {
 
-    @SuppressWarnings("unchecked")
     @Override
+    @SuppressWarnings("unchecked")
     public Object convert(Class type, Object value) {
       final StringTokenizer tokenizer =
           new StringTokenizer(value.toString().trim(), COMMA_SEPARATOR);
@@ -355,8 +355,8 @@ public abstract class AbstractAutomaticBean implements Configurable, Contextuali
     /** Constant for optimization. */
     private static final AccessModifierOption[] EMPTY_MODIFIER_ARRAY = new AccessModifierOption[0];
 
-    @SuppressWarnings("unchecked")
     @Override
+    @SuppressWarnings("unchecked")
     public Object convert(Class type, Object value) {
       // Converts to a String and trims it for the tokenizer.
       final StringTokenizer tokenizer =
--- a/src/main/java/com/puppycrawl/tools/checkstyle/Checker.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/Checker.java
@@ -19,6 +19,9 @@
 
 package com.puppycrawl.tools.checkstyle;
 
+import static java.util.stream.Collectors.toUnmodifiableList;
+import static java.util.stream.Collectors.toUnmodifiableSet;
+
 import com.puppycrawl.tools.checkstyle.api.AuditEvent;
 import com.puppycrawl.tools.checkstyle.api.AuditListener;
 import com.puppycrawl.tools.checkstyle.api.BeforeExecutionFileFilter;
@@ -50,7 +53,6 @@ import java.util.Locale;
 import java.util.Set;
 import java.util.SortedSet;
 import java.util.TreeSet;
-import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -215,7 +217,7 @@ public class Checker extends AbstractAutomaticBean implements MessageDispatcher,
     final List<File> targetFiles =
         files.stream()
             .filter(file -> CommonUtil.matchesFileExtension(file, fileExtensions))
-            .collect(Collectors.toUnmodifiableList());
+            .collect(toUnmodifiableList());
     processFiles(targetFiles);
 
     // Finish up
@@ -244,7 +246,7 @@ public class Checker extends AbstractAutomaticBean implements MessageDispatcher,
             resource -> {
               return ((ExternalResourceHolder) resource).getExternalResourceLocations().stream();
             })
-        .collect(Collectors.toUnmodifiableSet());
+        .collect(toUnmodifiableSet());
   }
 
   /** Notify all listeners about the audit start. */
--- a/src/main/java/com/puppycrawl/tools/checkstyle/ConfigurationLoader.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/ConfigurationLoader.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle;
 
+import static com.google.common.base.Preconditions.checkState;
+
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
 import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.api.SeverityLevel;
@@ -523,9 +525,7 @@ public final class ConfigurationLoader {
         final DefaultConfiguration top = configStack.peek();
         top.addMessage(key, value);
       } else {
-        if (!METADATA.equals(qName)) {
-          throw new IllegalStateException("Unknown name:" + qName + ".");
-        }
+        checkState(METADATA.equals(qName), "Unknown name:%s.", qName);
       }
     }
 
--- a/src/main/java/com/puppycrawl/tools/checkstyle/DefaultLogger.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/DefaultLogger.java
@@ -19,6 +19,9 @@
 
 package com.puppycrawl.tools.checkstyle;
 
+import static com.google.common.base.Preconditions.checkArgument;
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import com.puppycrawl.tools.checkstyle.api.AuditEvent;
 import com.puppycrawl.tools.checkstyle.api.AuditListener;
 import com.puppycrawl.tools.checkstyle.api.AutomaticBean;
@@ -27,7 +30,6 @@ import java.io.OutputStream;
 import java.io.OutputStreamWriter;
 import java.io.PrintWriter;
 import java.io.Writer;
-import java.nio.charset.StandardCharsets;
 
 /**
  * Simple plain logger for text output. This is maybe not very suitable for a text output into a
@@ -126,21 +128,17 @@ public class DefaultLogger extends AbstractAutomaticBean implements AuditListene
       OutputStream errorStream,
       OutputStreamOptions errorStreamOptions,
       AuditEventFormatter messageFormatter) {
-    if (infoStreamOptions == null) {
-      throw new IllegalArgumentException("Parameter infoStreamOptions can not be null");
-    }
+    checkArgument(infoStreamOptions != null, "Parameter infoStreamOptions can not be null");
     closeInfo = infoStreamOptions == OutputStreamOptions.CLOSE;
-    if (errorStreamOptions == null) {
-      throw new IllegalArgumentException("Parameter errorStreamOptions can not be null");
-    }
+    checkArgument(errorStreamOptions != null, "Parameter errorStreamOptions can not be null");
     closeError = errorStreamOptions == OutputStreamOptions.CLOSE;
-    final Writer infoStreamWriter = new OutputStreamWriter(infoStream, StandardCharsets.UTF_8);
+    final Writer infoStreamWriter = new OutputStreamWriter(infoStream, UTF_8);
     infoWriter = new PrintWriter(infoStreamWriter);
 
     if (infoStream == errorStream) {
       errorWriter = infoWriter;
     } else {
-      final Writer errorStreamWriter = new OutputStreamWriter(errorStream, StandardCharsets.UTF_8);
+      final Writer errorStreamWriter = new OutputStreamWriter(errorStream, UTF_8);
       errorWriter = new PrintWriter(errorStreamWriter);
     }
     formatter = messageFormatter;
--- a/src/main/java/com/puppycrawl/tools/checkstyle/Definitions.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/Definitions.java
@@ -19,6 +19,7 @@
 
 package com.puppycrawl.tools.checkstyle;
 
+import com.google.common.collect.ImmutableSet;
 import java.util.Set;
 
 /** Contains constant definitions common to the package. */
@@ -29,7 +30,7 @@ public final class Definitions {
 
   /** Name of modules which are not checks, but are internal modules. */
   public static final Set<String> INTERNAL_MODULES =
-      Set.of(
+      ImmutableSet.of(
           "com.puppycrawl.tools.checkstyle.meta.JavadocMetadataScraper",
           "com.puppycrawl.tools.checkstyle.site.ClassAndPropertiesSettersJavadocScraper");
 
--- a/src/main/java/com/puppycrawl/tools/checkstyle/JavaAstVisitor.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/JavaAstVisitor.java
@@ -19,20 +19,22 @@
 
 package com.puppycrawl.tools.checkstyle;
 
+import static java.util.Objects.requireNonNullElseGet;
+import static java.util.stream.Collectors.toCollection;
+import static java.util.stream.Collectors.toUnmodifiableList;
+
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.grammar.java.JavaLanguageLexer;
 import com.puppycrawl.tools.checkstyle.grammar.java.JavaLanguageParser;
 import com.puppycrawl.tools.checkstyle.grammar.java.JavaLanguageParserBaseVisitor;
 import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
-import java.util.Objects;
 import java.util.Optional;
 import java.util.Queue;
 import java.util.concurrent.ConcurrentLinkedQueue;
-import java.util.stream.Collectors;
 import org.antlr.v4.runtime.BufferedTokenStream;
 import org.antlr.v4.runtime.CommonTokenStream;
 import org.antlr.v4.runtime.ParserRuleContext;
@@ -416,7 +418,7 @@ public final class JavaAstVisitor extends JavaLanguageParserBaseVisitor<DetailAs
         methodDef,
         ctx.children.stream()
             .filter(child -> !(child instanceof JavaLanguageParser.ArrayDeclaratorContext))
-            .collect(Collectors.toUnmodifiableList()));
+            .collect(toUnmodifiableList()));
 
     // We add C style array declarator brackets to TYPE ast
     final DetailAstImpl typeAst = (DetailAstImpl) methodDef.findFirstToken(TokenTypes.TYPE);
@@ -479,7 +481,7 @@ public final class JavaAstVisitor extends JavaLanguageParserBaseVisitor<DetailAs
     final List<ParseTree> children =
         ctx.children.stream()
             .filter(child -> !(child instanceof JavaLanguageParser.ArrayDeclaratorContext))
-            .collect(Collectors.toUnmodifiableList());
+            .collect(toUnmodifiableList());
     processChildren(methodDef, children);
 
     // We add C style array declarator brackets to TYPE ast
@@ -790,7 +792,7 @@ public final class JavaAstVisitor extends JavaLanguageParserBaseVisitor<DetailAs
     final DetailAstImpl dummyNode = new DetailAstImpl();
     // Since the TYPE AST is built by visitAnnotationMethodOrConstantRest(), we skip it
     // here (child [0])
-    processChildren(dummyNode, Collections.singletonList(ctx.children.get(1)));
+    processChildren(dummyNode, ImmutableList.of(ctx.children.get(1)));
     // We also append the SEMI token to the first child [size() - 1],
     // until https://github.com/checkstyle/checkstyle/issues/3151
     dummyNode.getFirstChild().addChild(create(ctx.SEMI()));
@@ -814,7 +816,7 @@ public final class JavaAstVisitor extends JavaLanguageParserBaseVisitor<DetailAs
         annotationFieldDef,
         ctx.children.stream()
             .filter(child -> !(child instanceof JavaLanguageParser.ArrayDeclaratorContext))
-            .collect(Collectors.toUnmodifiableList()));
+            .collect(toUnmodifiableList()));
 
     // We add C style array declarator brackets to TYPE ast
     final DetailAstImpl typeAst =
@@ -862,7 +864,7 @@ public final class JavaAstVisitor extends JavaLanguageParserBaseVisitor<DetailAs
         primaryCtorCall,
         ctx.children.stream()
             .filter(child -> !child.equals(ctx.LITERAL_SUPER()))
-            .collect(Collectors.toUnmodifiableList()));
+            .collect(toUnmodifiableList()));
     return primaryCtorCall;
   }
 
@@ -1100,7 +1102,7 @@ public final class JavaAstVisitor extends JavaLanguageParserBaseVisitor<DetailAs
         catchParameterDef,
         ctx.children.stream()
             .filter(child -> !(child instanceof JavaLanguageParser.VariableModifierContext))
-            .collect(Collectors.toUnmodifiableList()));
+            .collect(toUnmodifiableList()));
     return catchParameterDef;
   }
 
@@ -1431,8 +1433,7 @@ public final class JavaAstVisitor extends JavaLanguageParserBaseVisitor<DetailAs
 
     // We always add an 'ELIST' node
     final DetailAstImpl expressionList =
-        Optional.ofNullable(visit(ctx.expressionList()))
-            .orElseGet(() -> createImaginary(TokenTypes.ELIST));
+        requireNonNullElseGet(visit(ctx.expressionList()), () -> createImaginary(TokenTypes.ELIST));
 
     DetailAstPair.addAstChild(currentAst, expressionList);
     DetailAstPair.addAstChild(currentAst, create(ctx.RPAREN()));
@@ -1458,8 +1459,7 @@ public final class JavaAstVisitor extends JavaLanguageParserBaseVisitor<DetailAs
     methodCall.addChild(visit(ctx.id()));
     // We always add an 'ELIST' node
     final DetailAstImpl expressionList =
-        Optional.ofNullable(visit(ctx.expressionList()))
-            .orElseGet(() -> createImaginary(TokenTypes.ELIST));
+        requireNonNullElseGet(visit(ctx.expressionList()), () -> createImaginary(TokenTypes.ELIST));
 
     methodCall.addChild(expressionList);
     methodCall.addChild(create((Token) ctx.RPAREN().getPayload()));
@@ -1526,7 +1526,7 @@ public final class JavaAstVisitor extends JavaLanguageParserBaseVisitor<DetailAs
     final List<ParseTree> children =
         ctx.children.stream()
             .filter(child -> !child.equals(ctx.DOUBLE_COLON()))
-            .collect(Collectors.toUnmodifiableList());
+            .collect(toUnmodifiableList());
     processChildren(doubleColon, children);
     return doubleColon;
   }
@@ -1538,7 +1538,7 @@ public final class JavaAstVisitor extends JavaLanguageParserBaseVisitor<DetailAs
         root,
         ctx.children.stream()
             .filter(child -> !child.equals(ctx.QUESTION()))
-            .collect(Collectors.toUnmodifiableList()));
+            .collect(toUnmodifiableList()));
     return root;
   }
 
@@ -1565,7 +1565,7 @@ public final class JavaAstVisitor extends JavaLanguageParserBaseVisitor<DetailAs
       final Queue<DetailAstImpl> descendantList =
           binOpList.parallelStream()
               .map(this::getInnerBopAst)
-              .collect(Collectors.toCollection(ConcurrentLinkedQueue::new));
+              .collect(toCollection(ConcurrentLinkedQueue::new));
 
       bop.addChild(descendantList.poll());
       DetailAstImpl pointer = bop.getFirstChild();
@@ -1602,8 +1602,7 @@ public final class JavaAstVisitor extends JavaLanguageParserBaseVisitor<DetailAs
         create(TokenTypes.METHOD_CALL, (Token) ctx.LPAREN().getPayload());
     // We always add an 'ELIST' node
     final DetailAstImpl expressionList =
-        Optional.ofNullable(visit(ctx.expressionList()))
-            .orElseGet(() -> createImaginary(TokenTypes.ELIST));
+        requireNonNullElseGet(visit(ctx.expressionList()), () -> createImaginary(TokenTypes.ELIST));
 
     final DetailAstImpl dot = create(ctx.DOT());
     dot.addChild(visit(ctx.expr()));
@@ -1636,8 +1635,8 @@ public final class JavaAstVisitor extends JavaLanguageParserBaseVisitor<DetailAs
 
     // We add an 'PARAMETERS' node here whether it exists or not
     final DetailAstImpl parameters =
-        Optional.ofNullable(visit(ctx.formalParameterList()))
-            .orElseGet(() -> createImaginary(TokenTypes.PARAMETERS));
+        requireNonNullElseGet(
+            visit(ctx.formalParameterList()), () -> createImaginary(TokenTypes.PARAMETERS));
     addLastSibling(lparen, parameters);
     addLastSibling(lparen, create(ctx.RPAREN()));
     return lparen;
@@ -1717,7 +1716,7 @@ public final class JavaAstVisitor extends JavaLanguageParserBaseVisitor<DetailAs
 
   @Override
   public DetailAstImpl visitTemplateArgument(JavaLanguageParser.TemplateArgumentContext ctx) {
-    return Objects.requireNonNullElseGet(
+    return requireNonNullElseGet(
         visit(ctx.template()), () -> buildSimpleStringTemplateArgument(ctx));
   }
 
@@ -1773,7 +1772,7 @@ public final class JavaAstVisitor extends JavaLanguageParserBaseVisitor<DetailAs
 
     ctx.stringTemplateMiddle().stream()
         .map(this::buildStringTemplateMiddle)
-        .collect(Collectors.toUnmodifiableList())
+        .collect(toUnmodifiableList())
         .forEach(begin::addChild);
 
     final DetailAstImpl end = buildStringTemplateEnd(ctx);
@@ -2111,8 +2110,8 @@ public final class JavaAstVisitor extends JavaLanguageParserBaseVisitor<DetailAs
       root.addChild(dot);
 
       final DetailAstImpl expressionList =
-          Optional.ofNullable(visit(ctx.expressionList()))
-              .orElseGet(() -> createImaginary(TokenTypes.ELIST));
+          requireNonNullElseGet(
+              visit(ctx.expressionList()), () -> createImaginary(TokenTypes.ELIST));
       root.addChild(expressionList);
 
       root.addChild(create(ctx.RPAREN()));
@@ -2127,8 +2126,7 @@ public final class JavaAstVisitor extends JavaLanguageParserBaseVisitor<DetailAs
 
     // We always add an 'ELIST' node
     final DetailAstImpl expressionList =
-        Optional.ofNullable(visit(ctx.expressionList()))
-            .orElseGet(() -> createImaginary(TokenTypes.ELIST));
+        requireNonNullElseGet(visit(ctx.expressionList()), () -> createImaginary(TokenTypes.ELIST));
     addLastSibling(lparen, expressionList);
     addLastSibling(lparen, create(ctx.RPAREN()));
     return lparen;
--- a/src/main/java/com/puppycrawl/tools/checkstyle/JavadocPropertiesGenerator.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/JavadocPropertiesGenerator.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.api.DetailNode;
@@ -28,7 +30,6 @@ import com.puppycrawl.tools.checkstyle.utils.JavadocUtil;
 import java.io.File;
 import java.io.IOException;
 import java.io.PrintWriter;
-import java.nio.charset.StandardCharsets;
 import java.util.function.Consumer;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -92,7 +93,7 @@ public final class JavadocPropertiesGenerator {
    * @throws CheckstyleException if a javadoc comment can not be parsed
    */
   private static void writePropertiesFile(CliOptions options) throws CheckstyleException {
-    try (PrintWriter writer = new PrintWriter(options.outputFile, StandardCharsets.UTF_8)) {
+    try (PrintWriter writer = new PrintWriter(options.outputFile, UTF_8)) {
       final DetailAST top =
           JavaParser.parseFile(options.inputFile, JavaParser.Options.WITH_COMMENTS).getFirstChild();
       final DetailAST objBlock = getClassBody(top);
--- a/src/main/java/com/puppycrawl/tools/checkstyle/LocalizedMessage.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/LocalizedMessage.java
@@ -19,13 +19,14 @@
 
 package com.puppycrawl.tools.checkstyle;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import com.puppycrawl.tools.checkstyle.utils.UnmodifiableCollectionUtil;
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.io.Reader;
 import java.net.URL;
 import java.net.URLConnection;
-import java.nio.charset.StandardCharsets;
 import java.text.MessageFormat;
 import java.util.Locale;
 import java.util.MissingResourceException;
@@ -147,8 +148,7 @@ public class LocalizedMessage {
         final URLConnection connection = url.openConnection();
         if (connection != null) {
           connection.setUseCaches(!reload);
-          try (Reader streamReader =
-              new InputStreamReader(connection.getInputStream(), StandardCharsets.UTF_8)) {
+          try (Reader streamReader = new InputStreamReader(connection.getInputStream(), UTF_8)) {
             // Only this line is changed to make it read property files as UTF-8.
             resourceBundle = new PropertyResourceBundle(streamReader);
           }
--- a/src/main/java/com/puppycrawl/tools/checkstyle/Main.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/Main.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle;
 
+import static java.util.stream.Collectors.toCollection;
+
 import com.puppycrawl.tools.checkstyle.AbstractAutomaticBean.OutputStreamOptions;
 import com.puppycrawl.tools.checkstyle.api.AuditEvent;
 import com.puppycrawl.tools.checkstyle.api.AuditListener;
@@ -38,7 +40,6 @@ import java.util.ArrayList;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Locale;
-import java.util.Objects;
 import java.util.Properties;
 import java.util.logging.ConsoleHandler;
 import java.util.logging.Filter;
@@ -46,7 +47,6 @@ import java.util.logging.Level;
 import java.util.logging.LogRecord;
 import java.util.logging.Logger;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import picocli.CommandLine;
@@ -274,7 +274,7 @@ public final class Main {
       final String stringAst =
           AstTreeStringPrinter.printFileAst(file, JavaParser.Options.WITHOUT_COMMENTS);
       System.out.print(stringAst);
-    } else if (Objects.nonNull(options.xpath)) {
+    } else if (options.xpath != null) {
       final String branch = XpathUtil.printXpathBranch(options.xpath, filesToProcess.get(0));
       System.out.print(branch);
     } else if (options.printAstWithComments) {
@@ -791,7 +791,7 @@ public final class Main {
               .map(File::getAbsolutePath)
               .map(Pattern::quote)
               .map(pattern -> Pattern.compile("^" + pattern + "$"))
-              .collect(Collectors.toCollection(ArrayList::new));
+              .collect(toCollection(ArrayList::new));
       result.addAll(excludeRegex);
       return result;
     }
--- a/src/main/java/com/puppycrawl/tools/checkstyle/MetadataGeneratorLogger.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/MetadataGeneratorLogger.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import com.puppycrawl.tools.checkstyle.api.AuditEvent;
 import com.puppycrawl.tools.checkstyle.api.AuditListener;
 import com.puppycrawl.tools.checkstyle.api.SeverityLevel;
@@ -26,7 +28,6 @@ import java.io.OutputStream;
 import java.io.OutputStreamWriter;
 import java.io.PrintWriter;
 import java.io.Writer;
-import java.nio.charset.StandardCharsets;
 
 /** Simple logger for metadata generator util. */
 public class MetadataGeneratorLogger extends AbstractAutomaticBean implements AuditListener {
@@ -48,7 +49,7 @@ public class MetadataGeneratorLogger extends AbstractAutomaticBean implements Au
    */
   public MetadataGeneratorLogger(
       OutputStream outputStream, OutputStreamOptions outputStreamOptions) {
-    final Writer errorStreamWriter = new OutputStreamWriter(outputStream, StandardCharsets.UTF_8);
+    final Writer errorStreamWriter = new OutputStreamWriter(outputStream, UTF_8);
     errorWriter = new PrintWriter(errorStreamWriter);
     formatter = new AuditEventDefaultFormatter();
     closeErrorWriter = outputStreamOptions == OutputStreamOptions.CLOSE;
--- a/src/main/java/com/puppycrawl/tools/checkstyle/PackageNamesLoader.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/PackageNamesLoader.java
@@ -19,13 +19,14 @@
 
 package com.puppycrawl.tools.checkstyle;
 
+import static java.util.Collections.unmodifiableSet;
+
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
 import java.io.BufferedInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.URL;
 import java.util.ArrayDeque;
-import java.util.Collections;
 import java.util.Deque;
 import java.util.Enumeration;
 import java.util.HashMap;
@@ -137,7 +138,7 @@ public final class PackageNamesLoader extends XmlLoader {
       throw new CheckstyleException("unable to open one of package files", ex);
     }
 
-    return Collections.unmodifiableSet(result);
+    return unmodifiableSet(result);
   }
 
   /**
--- a/src/main/java/com/puppycrawl/tools/checkstyle/PackageObjectFactory.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/PackageObjectFactory.java
@@ -19,10 +19,18 @@
 
 package com.puppycrawl.tools.checkstyle;
 
+import static com.google.common.base.Preconditions.checkArgument;
+import static java.util.stream.Collectors.groupingBy;
+import static java.util.stream.Collectors.joining;
+import static java.util.stream.Collectors.mapping;
+import static java.util.stream.Collectors.toCollection;
+import static java.util.stream.Collectors.toUnmodifiableList;
+
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
 import com.puppycrawl.tools.checkstyle.utils.ModuleReflectionUtil;
 import java.io.IOException;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.LinkedHashSet;
@@ -31,7 +39,6 @@ import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Set;
 import java.util.function.Supplier;
-import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 /**
@@ -126,12 +133,8 @@ public class PackageObjectFactory implements ModuleFactory {
    */
   public PackageObjectFactory(
       Set<String> packageNames, ClassLoader moduleClassLoader, ModuleLoadOption moduleLoadOption) {
-    if (moduleClassLoader == null) {
-      throw new IllegalArgumentException(NULL_LOADER_MESSAGE);
-    }
-    if (packageNames.contains(null)) {
-      throw new IllegalArgumentException(NULL_PACKAGE_MESSAGE);
-    }
+    checkArgument(moduleClassLoader != null, NULL_LOADER_MESSAGE);
+    checkArgument(!packageNames.contains(null), NULL_PACKAGE_MESSAGE);
 
     // create a copy of the given set, but retain ordering
     packages = new LinkedHashSet<>(packageNames);
@@ -147,14 +150,10 @@ public class PackageObjectFactory implements ModuleFactory {
    * @throws IllegalArgumentException if moduleClassLoader is null or packageNames is null
    */
   public PackageObjectFactory(String packageName, ClassLoader moduleClassLoader) {
-    if (moduleClassLoader == null) {
-      throw new IllegalArgumentException(NULL_LOADER_MESSAGE);
-    }
-    if (packageName == null) {
-      throw new IllegalArgumentException(NULL_PACKAGE_MESSAGE);
-    }
+    checkArgument(moduleClassLoader != null, NULL_LOADER_MESSAGE);
+    checkArgument(packageName != null, NULL_PACKAGE_MESSAGE);
 
-    packages = Collections.singleton(packageName);
+    packages = ImmutableSet.of(packageName);
     this.moduleClassLoader = moduleClassLoader;
   }
 
@@ -272,7 +271,7 @@ public class PackageObjectFactory implements ModuleFactory {
       returnValue = createObject(fullModuleNames.iterator().next());
     } else {
       final String optionalNames =
-          fullModuleNames.stream().sorted().collect(Collectors.joining(STRING_SEPARATOR));
+          fullModuleNames.stream().sorted().collect(joining(STRING_SEPARATOR));
       final LocalizedMessage exceptionMessage =
           new LocalizedMessage(
               Definitions.CHECKSTYLE_BUNDLE,
@@ -299,12 +298,11 @@ public class PackageObjectFactory implements ModuleFactory {
       returnValue =
           ModuleReflectionUtil.getCheckstyleModules(packages, loader).stream()
               .collect(
-                  Collectors.groupingBy(
+                  groupingBy(
                       Class::getSimpleName,
-                      Collectors.mapping(
-                          Class::getCanonicalName, Collectors.toCollection(HashSet::new))));
+                      mapping(Class::getCanonicalName, toCollection(HashSet::new))));
     } catch (IOException ignore) {
-      returnValue = Collections.emptyMap();
+      returnValue = ImmutableMap.of();
     }
     return returnValue;
   }
@@ -318,8 +316,8 @@ public class PackageObjectFactory implements ModuleFactory {
   public static String getShortFromFullModuleNames(String fullName) {
     return NAME_TO_FULL_MODULE_NAME.entrySet().stream()
         .filter(entry -> entry.getValue().equals(fullName))
-        .map(Entry::getKey)
         .findFirst()
+        .map(Entry::getKey)
         .orElse(fullName);
   }
 
@@ -333,7 +331,7 @@ public class PackageObjectFactory implements ModuleFactory {
   private static String joinPackageNamesWithClassName(String className, Set<String> packages) {
     return packages.stream()
         .collect(
-            Collectors.joining(
+            joining(
                 PACKAGE_SEPARATOR + className + STRING_SEPARATOR,
                 "",
                 PACKAGE_SEPARATOR + className));
@@ -381,7 +379,7 @@ public class PackageObjectFactory implements ModuleFactory {
         packages.stream()
             .map(packageName -> packageName + PACKAGE_SEPARATOR + name)
             .flatMap(className -> Stream.of(className, className + CHECK_SUFFIX))
-            .collect(Collectors.toUnmodifiableList());
+            .collect(toUnmodifiableList());
     Object instance = null;
     for (String possibleName : possibleNames) {
       instance = createObject(possibleName);
--- a/src/main/java/com/puppycrawl/tools/checkstyle/PropertiesExpander.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/PropertiesExpander.java
@@ -19,10 +19,12 @@
 
 package com.puppycrawl.tools.checkstyle;
 
+import static com.google.common.base.Preconditions.checkArgument;
+import static java.util.function.Function.identity;
+import static java.util.stream.Collectors.toUnmodifiableMap;
+
 import java.util.Map;
 import java.util.Properties;
-import java.util.function.Function;
-import java.util.stream.Collectors;
 
 /** Resolves external properties from an underlying {@code Properties} object. */
 public final class PropertiesExpander implements PropertyResolver {
@@ -37,12 +39,10 @@ public final class PropertiesExpander implements PropertyResolver {
    * @throws IllegalArgumentException when properties argument is null
    */
   public PropertiesExpander(Properties properties) {
-    if (properties == null) {
-      throw new IllegalArgumentException("cannot pass null");
-    }
+    checkArgument(properties != null, "cannot pass null");
     values =
         properties.stringPropertyNames().stream()
-            .collect(Collectors.toUnmodifiableMap(Function.identity(), properties::getProperty));
+            .collect(toUnmodifiableMap(identity(), properties::getProperty));
   }
 
   @Override
--- a/src/main/java/com/puppycrawl/tools/checkstyle/PropertyCacheFile.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/PropertyCacheFile.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle;
 
+import static com.google.common.base.Preconditions.checkArgument;
+
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
 import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
@@ -94,12 +96,8 @@ public final class PropertyCacheFile {
    * @throws IllegalArgumentException when either arguments are null
    */
   public PropertyCacheFile(Configuration config, String fileName) {
-    if (config == null) {
-      throw new IllegalArgumentException("config can not be null");
-    }
-    if (fileName == null) {
-      throw new IllegalArgumentException("fileName can not be null");
-    }
+    checkArgument(config != null, "config can not be null");
+    checkArgument(fileName != null, "fileName can not be null");
     this.config = config;
     this.fileName = fileName;
   }
--- a/src/main/java/com/puppycrawl/tools/checkstyle/SarifLogger.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/SarifLogger.java
@@ -19,6 +19,9 @@
 
 package com.puppycrawl.tools.checkstyle;
 
+import static com.google.common.base.Preconditions.checkArgument;
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import com.puppycrawl.tools.checkstyle.api.AuditEvent;
 import com.puppycrawl.tools.checkstyle.api.AuditListener;
 import com.puppycrawl.tools.checkstyle.api.SeverityLevel;
@@ -29,7 +32,6 @@ import java.io.OutputStream;
 import java.io.OutputStreamWriter;
 import java.io.PrintWriter;
 import java.io.StringWriter;
-import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Locale;
@@ -107,10 +109,8 @@ public class SarifLogger extends AbstractAutomaticBean implements AuditListener
    */
   public SarifLogger(OutputStream outputStream, OutputStreamOptions outputStreamOptions)
       throws IOException {
-    if (outputStreamOptions == null) {
-      throw new IllegalArgumentException("Parameter outputStreamOptions can not be null");
-    }
-    writer = new PrintWriter(new OutputStreamWriter(outputStream, StandardCharsets.UTF_8));
+    checkArgument(outputStreamOptions != null, "Parameter outputStreamOptions can not be null");
+    writer = new PrintWriter(new OutputStreamWriter(outputStream, UTF_8));
     closeStream = outputStreamOptions == OutputStreamOptions.CLOSE;
     report = readResource("/com/puppycrawl/tools/checkstyle/sarif/SarifReport.template");
     resultLineColumn =
@@ -307,7 +307,7 @@ public class SarifLogger extends AbstractAutomaticBean implements AuditListener
         result.write(buffer, 0, length);
         length = inputStream.read(buffer);
       }
-      return result.toString(StandardCharsets.UTF_8);
+      return result.toString(UTF_8);
     }
   }
 }
--- a/src/main/java/com/puppycrawl/tools/checkstyle/SuppressionsStringPrinter.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/SuppressionsStringPrinter.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle;
 
+import static java.util.stream.Collectors.joining;
+
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.api.FileText;
@@ -30,7 +32,6 @@ import java.util.List;
 import java.util.Locale;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 
 /** Class for constructing xpath queries to suppress nodes with specified line and column number. */
 public final class SuppressionsStringPrinter {
@@ -98,6 +99,6 @@ public final class SuppressionsStringPrinter {
     final XpathQueryGenerator queryGenerator =
         new XpathQueryGenerator(detailAST, lineNumber, columnNumber, fileText, tabWidth);
     final List<String> suppressions = queryGenerator.generate();
-    return suppressions.stream().collect(Collectors.joining(LINE_SEPARATOR, "", LINE_SEPARATOR));
+    return suppressions.stream().collect(joining(LINE_SEPARATOR, "", LINE_SEPARATOR));
   }
 }
--- a/src/main/java/com/puppycrawl/tools/checkstyle/ThreadModeSettings.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/ThreadModeSettings.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle;
 
+import static com.google.common.base.Preconditions.checkArgument;
+
 import java.io.Serializable;
 
 /**
@@ -93,14 +95,12 @@ public class ThreadModeSettings implements Serializable {
    */
   public final String resolveName(String name) {
     if (checkerThreadsNumber > 1) {
-      if (CHECKER_MODULE_NAME.equals(name)) {
-        throw new IllegalArgumentException(
-            "Multi thread mode for Checker module is not implemented");
-      }
-      if (TREE_WALKER_MODULE_NAME.equals(name)) {
-        throw new IllegalArgumentException(
-            "Multi thread mode for TreeWalker module is not implemented");
-      }
+      checkArgument(
+          !CHECKER_MODULE_NAME.equals(name),
+          "Multi thread mode for Checker module is not implemented");
+      checkArgument(
+          !TREE_WALKER_MODULE_NAME.equals(name),
+          "Multi thread mode for TreeWalker module is not implemented");
     }
 
     return name;
--- a/src/main/java/com/puppycrawl/tools/checkstyle/TreeWalker.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/TreeWalker.java
@@ -19,6 +19,10 @@
 
 package com.puppycrawl.tools.checkstyle;
 
+import static java.util.Comparator.naturalOrder;
+import static java.util.Comparator.nullsLast;
+import static java.util.stream.Collectors.toUnmodifiableSet;
+
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck;
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
@@ -41,7 +45,6 @@ import java.util.Map;
 import java.util.Set;
 import java.util.SortedSet;
 import java.util.TreeSet;
-import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 /** Responsible for walking an abstract syntax tree and notifying interested checks at each node. */
@@ -371,7 +374,7 @@ public final class TreeWalker extends AbstractFileSetCheck implements ExternalRe
             resource -> {
               return ((ExternalResourceHolder) resource).getExternalResourceLocations().stream();
             })
-        .collect(Collectors.toUnmodifiableSet());
+        .collect(toUnmodifiableSet());
   }
 
   /**
@@ -403,8 +406,8 @@ public final class TreeWalker extends AbstractFileSetCheck implements ExternalRe
   private static SortedSet<AbstractCheck> createNewCheckSortedSet() {
     return new TreeSet<>(
         Comparator.<AbstractCheck, String>comparing(check -> check.getClass().getName())
-            .thenComparing(AbstractCheck::getId, Comparator.nullsLast(Comparator.naturalOrder()))
-            .thenComparing(AbstractCheck::hashCode));
+            .thenComparing(AbstractCheck::getId, nullsLast(naturalOrder()))
+            .thenComparingInt(AbstractCheck::hashCode));
   }
 
   /** State of AST. Indicates whether tree contains certain nodes. */
--- a/src/main/java/com/puppycrawl/tools/checkstyle/XMLLogger.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/XMLLogger.java
@@ -19,6 +19,10 @@
 
 package com.puppycrawl.tools.checkstyle;
 
+import static com.google.common.base.Preconditions.checkArgument;
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static java.util.Collections.synchronizedList;
+
 import com.puppycrawl.tools.checkstyle.api.AuditEvent;
 import com.puppycrawl.tools.checkstyle.api.AuditListener;
 import com.puppycrawl.tools.checkstyle.api.AutomaticBean;
@@ -28,9 +32,7 @@ import java.io.OutputStream;
 import java.io.OutputStreamWriter;
 import java.io.PrintWriter;
 import java.io.StringWriter;
-import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
@@ -90,10 +92,8 @@ public class XMLLogger extends AbstractAutomaticBean implements AuditListener {
    * @throws IllegalArgumentException if outputStreamOptions is null.
    */
   public XMLLogger(OutputStream outputStream, OutputStreamOptions outputStreamOptions) {
-    writer = new PrintWriter(new OutputStreamWriter(outputStream, StandardCharsets.UTF_8));
-    if (outputStreamOptions == null) {
-      throw new IllegalArgumentException("Parameter outputStreamOptions can not be null");
-    }
+    writer = new PrintWriter(new OutputStreamWriter(outputStream, UTF_8));
+    checkArgument(outputStreamOptions != null, "Parameter outputStreamOptions can not be null");
     closeStream = outputStreamOptions == OutputStreamOptions.CLOSE;
   }
 
@@ -328,10 +328,10 @@ public class XMLLogger extends AbstractAutomaticBean implements AuditListener {
   private static final class FileMessages {
 
     /** The file error events. */
-    private final List<AuditEvent> errors = Collections.synchronizedList(new ArrayList<>());
+    private final List<AuditEvent> errors = synchronizedList(new ArrayList<>());
 
     /** The file exceptions. */
-    private final List<Throwable> exceptions = Collections.synchronizedList(new ArrayList<>());
+    private final List<Throwable> exceptions = synchronizedList(new ArrayList<>());
 
     /**
      * Returns the file error events.
--- a/src/main/java/com/puppycrawl/tools/checkstyle/XpathFileGeneratorAuditListener.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/XpathFileGeneratorAuditListener.java
@@ -19,13 +19,14 @@
 
 package com.puppycrawl.tools.checkstyle;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import com.puppycrawl.tools.checkstyle.api.AuditEvent;
 import com.puppycrawl.tools.checkstyle.api.AuditListener;
 import java.io.File;
 import java.io.OutputStream;
 import java.io.OutputStreamWriter;
 import java.io.PrintWriter;
-import java.nio.charset.StandardCharsets;
 
 /**
  * Generates <b>suppressions.xml</b> file, based on violations occurred. See issue <a
@@ -54,7 +55,7 @@ public class XpathFileGeneratorAuditListener extends AbstractAutomaticBean
    */
   public XpathFileGeneratorAuditListener(
       OutputStream out, OutputStreamOptions outputStreamOptions) {
-    writer = new PrintWriter(new OutputStreamWriter(out, StandardCharsets.UTF_8));
+    writer = new PrintWriter(new OutputStreamWriter(out, UTF_8));
     closeStream = outputStreamOptions == OutputStreamOptions.CLOSE;
   }
 
--- a/src/main/java/com/puppycrawl/tools/checkstyle/ant/CheckstyleAntTask.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/ant/CheckstyleAntTask.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.ant;
 
+import static java.util.stream.Collectors.toUnmodifiableList;
+
 import com.puppycrawl.tools.checkstyle.AbstractAutomaticBean.OutputStreamOptions;
 import com.puppycrawl.tools.checkstyle.Checker;
 import com.puppycrawl.tools.checkstyle.ConfigurationLoader;
@@ -47,7 +49,6 @@ import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Properties;
-import java.util.stream.Collectors;
 import org.apache.tools.ant.BuildException;
 import org.apache.tools.ant.DirectoryScanner;
 import org.apache.tools.ant.Project;
@@ -580,7 +581,7 @@ public class CheckstyleAntTask extends Task {
     return Arrays.stream(fileNames)
         .map(name -> scanner.getBasedir() + File.separator + name)
         .map(File::new)
-        .collect(Collectors.toUnmodifiableList());
+        .collect(toUnmodifiableList());
   }
 
   /** Poor man enumeration for the formatter types. */
--- a/src/main/java/com/puppycrawl/tools/checkstyle/api/AbstractCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/api/AbstractCheck.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.api;
 
+import static java.util.Collections.unmodifiableSet;
+
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.util.Collections;
 import java.util.HashSet;
@@ -107,7 +109,7 @@ public abstract class AbstractCheck extends AbstractViolationReporter {
    * @return the set of token names
    */
   public final Set<String> getTokenNames() {
-    return Collections.unmodifiableSet(tokens);
+    return unmodifiableSet(tokens);
   }
 
   /**
--- a/src/main/java/com/puppycrawl/tools/checkstyle/api/AbstractFileSetCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/api/AbstractFileSetCheck.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.api;
 
+import static com.google.common.base.Preconditions.checkArgument;
+
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.io.File;
 import java.util.Arrays;
@@ -164,9 +166,7 @@ public abstract class AbstractFileSetCheck extends AbstractViolationReporter
    * @throws IllegalArgumentException is argument is null
    */
   public final void setFileExtensions(String... extensions) {
-    if (extensions == null) {
-      throw new IllegalArgumentException("Extensions array can not be null");
-    }
+    checkArgument(extensions != null, "Extensions array can not be null");
 
     fileExtensions = new String[extensions.length];
     for (int i = 0; i < extensions.length; i++) {
--- a/src/main/java/com/puppycrawl/tools/checkstyle/api/AuditEvent.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/api/AuditEvent.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.api;
 
+import static com.google.common.base.Preconditions.checkArgument;
+
 /**
  * Raw event for audit.
  *
@@ -69,9 +71,7 @@ public final class AuditEvent {
    * @throws IllegalArgumentException if {@code src} is {@code null}.
    */
   public AuditEvent(Object src, String fileName, Violation violation) {
-    if (src == null) {
-      throw new IllegalArgumentException("null source");
-    }
+    checkArgument(src != null, "null source");
 
     source = src;
     this.fileName = fileName;
--- a/src/main/java/com/puppycrawl/tools/checkstyle/api/BeforeExecutionFileFilterSet.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/api/BeforeExecutionFileFilterSet.java
@@ -19,7 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.api;
 
-import java.util.Collections;
+import static java.util.Collections.unmodifiableSet;
+
 import java.util.HashSet;
 import java.util.Set;
 
@@ -56,7 +57,7 @@ public final class BeforeExecutionFileFilterSet implements BeforeExecutionFileFi
    * @return the Filters of the filter set.
    */
   public Set<BeforeExecutionFileFilter> getBeforeExecutionFileFilters() {
-    return Collections.unmodifiableSet(beforeExecutionFileFilters);
+    return unmodifiableSet(beforeExecutionFileFilters);
   }
 
   @Override
--- a/src/main/java/com/puppycrawl/tools/checkstyle/api/FileContents.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/api/FileContents.java
@@ -19,12 +19,13 @@
 
 package com.puppycrawl.tools.checkstyle.api;
 
+import static java.util.Collections.unmodifiableMap;
+
 import com.puppycrawl.tools.checkstyle.grammar.CommentListener;
 import com.puppycrawl.tools.checkstyle.utils.CheckUtil;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -293,7 +294,7 @@ public final class FileContents implements CommentListener {
    * @return the Map of comments
    */
   public Map<Integer, TextBlock> getSingleLineComments() {
-    return Collections.unmodifiableMap(cppComments);
+    return unmodifiableMap(cppComments);
   }
 
   /**
@@ -303,7 +304,7 @@ public final class FileContents implements CommentListener {
    * @return the map of comments
    */
   public Map<Integer, List<TextBlock>> getBlockComments() {
-    return Collections.unmodifiableMap(clangComments);
+    return unmodifiableMap(clangComments);
   }
 
   /**
--- a/src/main/java/com/puppycrawl/tools/checkstyle/api/FilterSet.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/api/FilterSet.java
@@ -19,7 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.api;
 
-import java.util.Collections;
+import static java.util.Collections.unmodifiableSet;
+
 import java.util.HashSet;
 import java.util.Set;
 
@@ -56,7 +57,7 @@ public class FilterSet implements Filter {
    * @return the Filters of the filter set.
    */
   public Set<Filter> getFilters() {
-    return Collections.unmodifiableSet(filters);
+    return unmodifiableSet(filters);
   }
 
   @Override
--- a/src/main/java/com/puppycrawl/tools/checkstyle/api/SeverityLevelCounter.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/api/SeverityLevelCounter.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.api;
 
+import static com.google.common.base.Preconditions.checkArgument;
+
 import java.util.concurrent.atomic.AtomicInteger;
 
 /**
@@ -40,9 +42,7 @@ public final class SeverityLevelCounter implements AuditListener {
    * @throws IllegalArgumentException when level is null
    */
   public SeverityLevelCounter(SeverityLevel level) {
-    if (level == null) {
-      throw new IllegalArgumentException("'level' cannot be null");
-    }
+    checkArgument(level != null, "'level' cannot be null");
     this.level = level;
   }
 
--- a/src/main/java/com/puppycrawl/tools/checkstyle/api/Violation.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/api/Violation.java
@@ -385,7 +385,7 @@ public final class Violation implements Comparable<Violation> {
         && Objects.equals(columnNo, violation.columnNo)
         && Objects.equals(columnCharIndex, violation.columnCharIndex)
         && Objects.equals(tokenType, violation.tokenType)
-        && Objects.equals(severityLevel, violation.severityLevel)
+        && severityLevel == violation.severityLevel
         && Objects.equals(moduleId, violation.moduleId)
         && Objects.equals(key, violation.key)
         && Objects.equals(bundle, violation.bundle)
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/AvoidEscapedUnicodeCharactersCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/AvoidEscapedUnicodeCharactersCheck.java
@@ -265,8 +265,8 @@ public class AvoidEscapedUnicodeCharactersCheck extends AbstractCheck {
   }
 
   // suppress deprecation until https://github.com/checkstyle/checkstyle/issues/11166
-  @SuppressWarnings("deprecation")
   @Override
+  @SuppressWarnings("deprecation")
   public void beginTree(DetailAST rootAST) {
     singlelineComments = getFileContents().getSingleLineComments();
     blockComments = getFileContents().getBlockComments();
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/LineSeparatorOption.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/LineSeparatorOption.java
@@ -19,7 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.checks;
 
-import java.nio.charset.StandardCharsets;
+import static java.nio.charset.StandardCharsets.US_ASCII;
+
 import java.util.Arrays;
 
 /**
@@ -55,7 +56,7 @@ public enum LineSeparatorOption {
    * @param sep the line separator, e.g. "\r\n"
    */
   LineSeparatorOption(String sep) {
-    lineSeparator = sep.getBytes(StandardCharsets.US_ASCII);
+    lineSeparator = sep.getBytes(US_ASCII);
   }
 
   /**
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/OrderedPropertiesCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/OrderedPropertiesCheck.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.checks;
 
+import static java.util.Collections.enumeration;
+
 import com.puppycrawl.tools.checkstyle.StatelessCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck;
 import com.puppycrawl.tools.checkstyle.api.FileText;
@@ -27,7 +29,6 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.nio.file.Files;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.Enumeration;
 import java.util.Iterator;
 import java.util.List;
@@ -191,7 +192,7 @@ public class OrderedPropertiesCheck extends AbstractFileSetCheck {
     /** Returns a copy of the keys. */
     @Override
     public Enumeration<Object> keys() {
-      return Collections.enumeration(keyList);
+      return enumeration(keyList);
     }
 
     /**
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/SuppressWarningsHolder.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/SuppressWarningsHolder.java
@@ -19,12 +19,14 @@
 
 package com.puppycrawl.tools.checkstyle.checks;
 
+import static com.google.common.base.Preconditions.checkArgument;
+
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.StatelessCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.AuditEvent;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.LinkedList;
 import java.util.List;
@@ -296,7 +298,7 @@ public class SuppressWarningsHolder extends AbstractCheck {
    */
   private static List<String> getAllAnnotationValues(DetailAST ast) {
     // get values of annotation
-    List<String> values = Collections.emptyList();
+    List<String> values = ImmutableList.of();
     final DetailAST lparenAST = ast.findFirstToken(TokenTypes.LPAREN);
     if (lparenAST != null) {
       final DetailAST nextAST = lparenAST.getNextSibling();
@@ -378,9 +380,7 @@ public class SuppressWarningsHolder extends AbstractCheck {
    * @throws IllegalArgumentException if the AST is invalid
    */
   private static String getIdentifier(DetailAST ast) {
-    if (ast == null) {
-      throw new IllegalArgumentException("Identifier AST expected, but get null.");
-    }
+    checkArgument(ast != null, "Identifier AST expected, but get null.");
     final String identifier;
     if (ast.getType() == TokenTypes.IDENT) {
       identifier = ast.getText();
@@ -436,7 +436,7 @@ public class SuppressWarningsHolder extends AbstractCheck {
     final List<String> annotationValues;
     switch (ast.getType()) {
       case TokenTypes.EXPR:
-        annotationValues = Collections.singletonList(getStringExpr(ast));
+        annotationValues = ImmutableList.of(getStringExpr(ast));
         break;
       case TokenTypes.ANNOTATION_ARRAY_INIT:
         annotationValues = findAllExpressionsInChildren(ast);
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/TranslationCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/TranslationCheck.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.checks;
 
+import static java.util.stream.Collectors.toUnmodifiableSet;
+
 import com.puppycrawl.tools.checkstyle.Definitions;
 import com.puppycrawl.tools.checkstyle.GlobalStatefulCheck;
 import com.puppycrawl.tools.checkstyle.LocalizedMessage;
@@ -46,7 +48,6 @@ import java.util.TreeSet;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
@@ -228,7 +229,7 @@ public class TranslationCheck extends AbstractFileSetCheck {
    * @since 6.11
    */
   public void setRequiredTranslations(String... translationCodes) {
-    requiredTranslations = Arrays.stream(translationCodes).collect(Collectors.toUnmodifiableSet());
+    requiredTranslations = Arrays.stream(translationCodes).collect(toUnmodifiableSet());
     validateUserSpecifiedLanguageCodes(requiredTranslations);
   }
 
@@ -501,7 +502,7 @@ public class TranslationCheck extends AbstractFileSetCheck {
       final Set<String> missingKeys =
           keysThatMustExist.stream()
               .filter(key -> !currentFileKeys.contains(key))
-              .collect(Collectors.toUnmodifiableSet());
+              .collect(toUnmodifiableSet());
       if (!missingKeys.isEmpty()) {
         final MessageDispatcher dispatcher = getMessageDispatcher();
         final String path = fileKey.getKey().getAbsolutePath();
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/UncommentedMainCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/UncommentedMainCheck.java
@@ -19,6 +19,7 @@
 
 package com.puppycrawl.tools.checkstyle.checks;
 
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
@@ -60,7 +61,7 @@ public class UncommentedMainCheck extends AbstractCheck {
 
   /** Set of possible String array types. */
   private static final Set<String> STRING_PARAMETER_NAMES =
-      Set.of(
+      ImmutableSet.of(
           String[].class.getCanonicalName(),
           String.class.getCanonicalName(),
           String[].class.getSimpleName(),
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/annotation/MissingOverrideCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/annotation/MissingOverrideCheck.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.checks.annotation;
 
+import static java.util.Objects.requireNonNullElse;
+
 import com.puppycrawl.tools.checkstyle.StatelessCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
@@ -152,8 +154,7 @@ public final class MissingOverrideCheck extends AbstractCheck {
     final DetailAST startNode;
     if (modifiers.hasChildren()) {
       startNode =
-          Optional.ofNullable(ast.getFirstChild().findFirstToken(TokenTypes.ANNOTATION))
-              .orElse(modifiers);
+          requireNonNullElse(ast.getFirstChild().findFirstToken(TokenTypes.ANNOTATION), modifiers);
     } else {
       startNode = ast.findFirstToken(TokenTypes.TYPE);
     }
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/annotation/SuppressWarningsCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/annotation/SuppressWarningsCheck.java
@@ -19,13 +19,14 @@
 
 package com.puppycrawl.tools.checkstyle.checks.annotation;
 
+import static java.util.Objects.requireNonNullElse;
+
 import com.puppycrawl.tools.checkstyle.StatelessCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.AnnotationUtil;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
-import java.util.Objects;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -162,7 +163,7 @@ public class SuppressWarningsCheck extends AbstractCheck {
       final DetailAST token = warningHolder.findFirstToken(TokenTypes.ANNOTATION_MEMBER_VALUE_PAIR);
 
       // case like '@SuppressWarnings(value = UNUSED)'
-      final DetailAST parent = Objects.requireNonNullElse(token, warningHolder);
+      final DetailAST parent = requireNonNullElse(token, warningHolder);
       DetailAST warning = parent.findFirstToken(TokenTypes.EXPR);
 
       // rare case with empty array ex: @SuppressWarnings({})
@@ -242,10 +243,10 @@ public class SuppressWarningsCheck extends AbstractCheck {
     final DetailAST annValuePair =
         annotation.findFirstToken(TokenTypes.ANNOTATION_MEMBER_VALUE_PAIR);
 
-    final DetailAST annArrayInitParent = Objects.requireNonNullElse(annValuePair, annotation);
+    final DetailAST annArrayInitParent = requireNonNullElse(annValuePair, annotation);
     final DetailAST annArrayInit =
         annArrayInitParent.findFirstToken(TokenTypes.ANNOTATION_ARRAY_INIT);
-    return Objects.requireNonNullElse(annArrayInit, annotation);
+    return requireNonNullElse(annArrayInit, annotation);
   }
 
   /**
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/FallThroughCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/FallThroughCheck.java
@@ -370,7 +370,7 @@ public class FallThroughCheck extends AbstractCheck {
     return Optional.ofNullable(getNextNonCommentAst(ast))
         .map(DetailAST::getPreviousSibling)
         .map(previous -> previous.getFirstChild().getText())
-        .map(text -> reliefPattern.matcher(text).find())
-        .orElse(Boolean.FALSE);
+        .filter(text -> reliefPattern.matcher(text).find())
+        .isPresent();
   }
 }
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalCatchCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalCatchCheck.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.checks.coding;
 
+import static java.util.stream.Collectors.toCollection;
+
 import com.puppycrawl.tools.checkstyle.StatelessCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
@@ -28,7 +30,6 @@ import com.puppycrawl.tools.checkstyle.utils.CheckUtil;
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 /**
  * Checks that certain exception types do not appear in a {@code catch} statement.
@@ -74,7 +75,7 @@ public final class IllegalCatchCheck extends AbstractCheck {
                 "java.lang.RuntimeException",
                 "java.lang.Throwable",
               })
-          .collect(Collectors.toCollection(HashSet::new));
+          .collect(toCollection(HashSet::new));
 
   /**
    * Setter to specify exception class names to reject.
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalInstantiationCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalInstantiationCheck.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.checks.coding;
 
+import static java.util.stream.Collectors.toUnmodifiableSet;
+
 import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
@@ -28,7 +30,6 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 /**
  * Checks for illegal instantiations where a factory method is preferred.
@@ -314,6 +315,6 @@ public class IllegalInstantiationCheck extends AbstractCheck {
    * @since 3.0
    */
   public void setClasses(String... names) {
-    classes = Arrays.stream(names).collect(Collectors.toUnmodifiableSet());
+    classes = Arrays.stream(names).collect(toUnmodifiableSet());
   }
 }
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalThrowsCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalThrowsCheck.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.checks.coding;
 
+import static java.util.stream.Collectors.toCollection;
+
 import com.puppycrawl.tools.checkstyle.StatelessCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
@@ -30,7 +32,6 @@ import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 /**
  * Checks that specified types are not declared to be thrown. Declaring that a method throws {@code
@@ -69,7 +70,7 @@ public final class IllegalThrowsCheck extends AbstractCheck {
               new String[] {
                 "finalize",
               })
-          .collect(Collectors.toCollection(HashSet::new));
+          .collect(toCollection(HashSet::new));
 
   /** Specify throw class names to reject. */
   private final Set<String> illegalClassNames =
@@ -82,7 +83,7 @@ public final class IllegalThrowsCheck extends AbstractCheck {
                 "java.lang.RuntimeException",
                 "java.lang.Throwable",
               })
-          .collect(Collectors.toCollection(HashSet::new));
+          .collect(toCollection(HashSet::new));
 
   /**
    * Allow to ignore checking overridden methods (marked with {@code Override} or {@code
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalTokenTextCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalTokenTextCheck.java
@@ -19,12 +19,14 @@
 
 package com.puppycrawl.tools.checkstyle.checks.coding;
 
+import static java.util.Objects.requireNonNullElse;
+import static java.util.regex.Pattern.CASE_INSENSITIVE;
+
 import com.puppycrawl.tools.checkstyle.StatelessCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
-import java.util.Objects;
 import java.util.regex.Pattern;
 
 /**
@@ -125,7 +127,7 @@ public class IllegalTokenTextCheck extends AbstractCheck {
    * @since 3.2
    */
   public void setMessage(String message) {
-    this.message = Objects.requireNonNullElse(message, "");
+    this.message = requireNonNullElse(message, "");
   }
 
   /**
@@ -157,7 +159,7 @@ public class IllegalTokenTextCheck extends AbstractCheck {
   private void updateRegexp() {
     final int compileFlags;
     if (ignoreCase) {
-      compileFlags = Pattern.CASE_INSENSITIVE;
+      compileFlags = CASE_INSENSITIVE;
     } else {
       compileFlags = 0;
     }
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/MatchXpathCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/MatchXpathCheck.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.checks.coding;
 
+import static java.util.stream.Collectors.toUnmodifiableList;
+
 import com.puppycrawl.tools.checkstyle.StatelessCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
@@ -26,7 +28,6 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import com.puppycrawl.tools.checkstyle.xpath.AbstractNode;
 import com.puppycrawl.tools.checkstyle.xpath.RootNode;
 import java.util.List;
-import java.util.stream.Collectors;
 import net.sf.saxon.Configuration;
 import net.sf.saxon.om.Item;
 import net.sf.saxon.sxpath.XPathDynamicContext;
@@ -142,7 +143,7 @@ public class MatchXpathCheck extends AbstractCheck {
       final List<Item> matchingItems = xpathExpression.evaluate(xpathDynamicContext);
       return matchingItems.stream()
           .map(item -> (DetailAST) ((AbstractNode) item).getUnderlyingNode())
-          .collect(Collectors.toUnmodifiableList());
+          .collect(toUnmodifiableList());
     } catch (XPathException ex) {
       throw new IllegalStateException("Evaluation of Xpath query failed: " + query, ex);
     }
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/ModifiedControlVariableCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/ModifiedControlVariableCheck.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.checks.coding;
 
+import static java.util.stream.Collectors.toUnmodifiableSet;
+
 import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
@@ -31,7 +33,6 @@ import java.util.HashSet;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 /**
  * Checks that for loop control variables are not modified inside the for block. An example is:
@@ -295,7 +296,7 @@ public final class ModifiedControlVariableCheck extends AbstractCheck {
     final Set<String> iteratingVariables = getForIteratorVariables(ast);
     return initializedVariables.stream()
         .filter(iteratingVariables::contains)
-        .collect(Collectors.toUnmodifiableSet());
+        .collect(toUnmodifiableSet());
   }
 
   /**
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/ParameterAssignmentCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/ParameterAssignmentCheck.java
@@ -19,6 +19,7 @@
 
 package com.puppycrawl.tools.checkstyle.checks.coding;
 
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
@@ -26,7 +27,6 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CheckUtil;
 import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
 import java.util.ArrayDeque;
-import java.util.Collections;
 import java.util.Deque;
 import java.util.HashSet;
 import java.util.Set;
@@ -99,7 +99,7 @@ public final class ParameterAssignmentCheck extends AbstractCheck {
   public void beginTree(DetailAST rootAST) {
     // clear data
     parameterNamesStack.clear();
-    parameterNames = Collections.emptySet();
+    parameterNames = ImmutableSet.of();
   }
 
   @Override
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/UnusedLocalVariableCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/UnusedLocalVariableCheck.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.checks.coding;
 
+import static java.util.stream.Collectors.toUnmodifiableList;
+
 import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
@@ -36,7 +38,6 @@ import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 /**
  * Checks that a local variable is declared and/or assigned, but not used. Doesn't support <a
@@ -480,7 +481,7 @@ public class UnusedLocalVariableCheck extends AbstractCheck {
             typeDeclDesc -> {
               return hasSameNameAsSuperClass(superClassName, typeDeclDesc);
             })
-        .collect(Collectors.toUnmodifiableList());
+        .collect(toUnmodifiableList());
   }
 
   /**
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/design/DesignForExtensionCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/design/DesignForExtensionCheck.java
@@ -19,6 +19,9 @@
 
 package com.puppycrawl.tools.checkstyle.checks.design;
 
+import static java.util.Objects.requireNonNullElse;
+import static java.util.stream.Collectors.toUnmodifiableSet;
+
 import com.puppycrawl.tools.checkstyle.StatelessCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
@@ -28,13 +31,11 @@ import com.puppycrawl.tools.checkstyle.utils.JavadocUtil;
 import com.puppycrawl.tools.checkstyle.utils.ScopeUtil;
 import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
 import java.util.Arrays;
-import java.util.Objects;
 import java.util.Optional;
 import java.util.Set;
 import java.util.function.Predicate;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 
 /**
  * Checks that classes are designed for extension (subclass creation).
@@ -180,7 +181,7 @@ public class DesignForExtensionCheck extends AbstractCheck {
               new String[] {
                 "Test", "Before", "After", "BeforeClass", "AfterClass",
               })
-          .collect(Collectors.toUnmodifiableSet());
+          .collect(toUnmodifiableSet());
 
   /**
    * Specify the comment text pattern which qualifies a method as designed for extension. Supports
@@ -195,8 +196,7 @@ public class DesignForExtensionCheck extends AbstractCheck {
    * @since 7.2
    */
   public void setIgnoredAnnotations(String... ignoredAnnotations) {
-    this.ignoredAnnotations =
-        Arrays.stream(ignoredAnnotations).collect(Collectors.toUnmodifiableSet());
+    this.ignoredAnnotations = Arrays.stream(ignoredAnnotations).collect(toUnmodifiableSet());
   }
 
   /**
@@ -397,7 +397,7 @@ public class DesignForExtensionCheck extends AbstractCheck {
    */
   private static String getAnnotationName(DetailAST annotation) {
     final DetailAST dotAst = annotation.findFirstToken(TokenTypes.DOT);
-    final DetailAST parent = Objects.requireNonNullElse(dotAst, annotation);
+    final DetailAST parent = requireNonNullElse(dotAst, annotation);
     return parent.findFirstToken(TokenTypes.IDENT).getText();
   }
 
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/design/FinalClassCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/design/FinalClassCheck.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.checks.design;
 
+import static java.util.Comparator.comparingInt;
+
 import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
@@ -310,7 +312,7 @@ public class FinalClassCheck extends AbstractCheck {
   private Optional<ClassDesc> getNearestClassWithSameName(
       String className, ToIntFunction<ClassDesc> countProvider) {
     final String dotAndClassName = PACKAGE_SEPARATOR.concat(className);
-    final Comparator<ClassDesc> longestMatch = Comparator.comparingInt(countProvider);
+    final Comparator<ClassDesc> longestMatch = comparingInt(countProvider);
     return innerClasses.entrySet().stream()
         .filter(entry -> entry.getKey().endsWith(dotAndClassName))
         .map(Map.Entry::getValue)
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/design/ThrowsCountCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/design/ThrowsCountCheck.java
@@ -19,11 +19,12 @@
 
 package com.puppycrawl.tools.checkstyle.checks.design;
 
+import static java.util.Objects.requireNonNullElse;
+
 import com.puppycrawl.tools.checkstyle.StatelessCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
-import java.util.Objects;
 
 /**
  * Restricts throws statements to a specified count. Methods with "Override" or "java.lang.Override"
@@ -167,7 +168,7 @@ public final class ThrowsCountCheck extends AbstractCheck {
    */
   private static String getAnnotationName(DetailAST annotation) {
     final DetailAST dotAst = annotation.findFirstToken(TokenTypes.DOT);
-    final DetailAST parent = Objects.requireNonNullElse(dotAst, annotation);
+    final DetailAST parent = requireNonNullElse(dotAst, annotation);
     return parent.findFirstToken(TokenTypes.IDENT).getText();
   }
 
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/design/VisibilityModifierCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/design/VisibilityModifierCheck.java
@@ -19,6 +19,9 @@
 
 package com.puppycrawl.tools.checkstyle.checks.design;
 
+import static java.util.stream.Collectors.toCollection;
+
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
@@ -33,7 +36,6 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 
 /**
  * Checks visibility of class members. Only static final, immutable or annotated by specified
@@ -152,7 +154,7 @@ public class VisibilityModifierCheck extends AbstractCheck {
 
   /** Default ignore annotations canonical names. */
   private static final Set<String> DEFAULT_IGNORE_ANNOTATIONS =
-      Set.of(
+      ImmutableSet.of(
           "org.junit.Rule",
           "org.junit.ClassRule",
           "com.google.common.annotations.VisibleForTesting");
@@ -685,7 +687,7 @@ public class VisibilityModifierCheck extends AbstractCheck {
   private static Set<String> getClassShortNames(Set<String> canonicalClassNames) {
     return canonicalClassNames.stream()
         .map(CommonUtil::baseClassName)
-        .collect(Collectors.toCollection(HashSet::new));
+        .collect(toCollection(HashSet::new));
   }
 
   /**
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/header/AbstractHeaderCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/header/AbstractHeaderCheck.java
@@ -19,6 +19,9 @@
 
 package com.puppycrawl.tools.checkstyle.checks.header;
 
+import static com.google.common.base.Preconditions.checkArgument;
+
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.PropertyType;
 import com.puppycrawl.tools.checkstyle.XdocsPropertyType;
 import com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck;
@@ -35,7 +38,6 @@ import java.net.URI;
 import java.nio.charset.Charset;
 import java.nio.charset.UnsupportedCharsetException;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 import java.util.Set;
 import java.util.regex.Pattern;
@@ -116,10 +118,9 @@ public abstract class AbstractHeaderCheck extends AbstractFileSetCheck
    * @throws IllegalArgumentException if header has already been set
    */
   private void checkHeaderNotInitialized() {
-    if (!readerLines.isEmpty()) {
-      throw new IllegalArgumentException(
-          "header has already been set - " + "set either header or headerFile, not both");
-    }
+    checkArgument(
+        readerLines.isEmpty(),
+        "header has already been set - " + "set either header or headerFile, not both");
   }
 
   /**
@@ -190,9 +191,9 @@ public abstract class AbstractHeaderCheck extends AbstractFileSetCheck
     final Set<String> result;
 
     if (headerFile == null) {
-      result = Collections.emptySet();
+      result = ImmutableSet.of();
     } else {
-      result = Collections.singleton(headerFile.toString());
+      result = ImmutableSet.of(headerFile.toString());
     }
 
     return result;
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/header/RegexpHeaderCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/header/RegexpHeaderCheck.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.checks.header;
 
+import static com.google.common.base.Preconditions.checkArgument;
+
 import com.puppycrawl.tools.checkstyle.StatelessCheck;
 import com.puppycrawl.tools.checkstyle.api.FileText;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
@@ -263,9 +265,7 @@ public class RegexpHeaderCheck extends AbstractHeaderCheck {
   @Override
   public void setHeader(String header) {
     if (!CommonUtil.isBlank(header)) {
-      if (!CommonUtil.isPatternValid(header)) {
-        throw new IllegalArgumentException("Unable to parse format: " + header);
-      }
+      checkArgument(CommonUtil.isPatternValid(header), "Unable to parse format: %s", header);
       super.setHeader(header);
     }
   }
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/imports/CustomImportOrderCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/imports/CustomImportOrderCheck.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.checks.imports;
 
+import static com.google.common.base.Preconditions.checkArgument;
+
 import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
@@ -649,10 +651,10 @@ public class CustomImportOrderCheck extends AbstractCheck {
     } else if (ruleStr.startsWith(SAME_PACKAGE_RULE_GROUP)) {
       final String rule = ruleStr.substring(ruleStr.indexOf('(') + 1, ruleStr.indexOf(')'));
       samePackageMatchingDepth = Integer.parseInt(rule);
-      if (samePackageMatchingDepth <= 0) {
-        throw new IllegalArgumentException(
-            "SAME_PACKAGE rule parameter should be positive integer: " + ruleStr);
-      }
+      checkArgument(
+          samePackageMatchingDepth > 0,
+          "SAME_PACKAGE rule parameter should be positive integer: %s",
+          ruleStr);
       customImportOrderRules.add(SAME_PACKAGE_RULE_GROUP);
     } else {
       throw new IllegalStateException("Unexpected rule: " + ruleStr);
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/imports/ImportControlCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/imports/ImportControlCheck.java
@@ -19,6 +19,7 @@
 
 package com.puppycrawl.tools.checkstyle.checks.imports;
 
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
@@ -27,7 +28,6 @@ import com.puppycrawl.tools.checkstyle.api.ExternalResourceHolder;
 import com.puppycrawl.tools.checkstyle.api.FullIdent;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import java.net.URI;
-import java.util.Collections;
 import java.util.Set;
 import java.util.regex.Pattern;
 
@@ -167,8 +167,8 @@ public class ImportControlCheck extends AbstractCheck implements ExternalResourc
   }
 
   // suppress deprecation until https://github.com/checkstyle/checkstyle/issues/11166
-  @SuppressWarnings("deprecation")
   @Override
+  @SuppressWarnings("deprecation")
   public void beginTree(DetailAST rootAST) {
     currentImportControl = null;
     processCurrentFile = path.matcher(getFilePath()).find();
@@ -207,7 +207,7 @@ public class ImportControlCheck extends AbstractCheck implements ExternalResourc
 
   @Override
   public Set<String> getExternalResourceLocations() {
-    return Collections.singleton(file.toString());
+    return ImmutableSet.of(file.toString());
   }
 
   /**
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/imports/ImportOrderCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/imports/ImportOrderCheck.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.checks.imports;
 
+import static com.google.common.base.Preconditions.checkArgument;
+
 import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
@@ -658,9 +660,7 @@ public class ImportOrderCheck extends AbstractCheck {
         // matches any package
         grp = Pattern.compile("");
       } else if (pkg.startsWith(FORWARD_SLASH)) {
-        if (!pkg.endsWith(FORWARD_SLASH)) {
-          throw new IllegalArgumentException("Invalid group: " + pkg);
-        }
+        checkArgument(pkg.endsWith(FORWARD_SLASH), "Invalid group: %s", pkg);
         pkg = pkg.substring(1, pkg.length() - 1);
         grp = Pattern.compile(pkg);
       } else {
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/AbstractJavadocCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/AbstractJavadocCheck.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.checks.javadoc;
 
+import static java.util.stream.Collectors.toUnmodifiableList;
+
 import com.puppycrawl.tools.checkstyle.JavadocDetailNodeParser;
 import com.puppycrawl.tools.checkstyle.JavadocDetailNodeParser.ParseErrorMessage;
 import com.puppycrawl.tools.checkstyle.JavadocDetailNodeParser.ParseStatus;
@@ -36,7 +38,6 @@ import java.util.HashSet;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 /**
  * Base class for Checks that process Javadoc comments.
@@ -182,9 +183,7 @@ public abstract class AbstractJavadocCheck extends AbstractCheck {
     validateDefaultJavadocTokens();
     if (javadocTokens.isEmpty()) {
       javadocTokens.addAll(
-          Arrays.stream(getDefaultJavadocTokens())
-              .boxed()
-              .collect(Collectors.toUnmodifiableList()));
+          Arrays.stream(getDefaultJavadocTokens()).boxed().collect(toUnmodifiableList()));
     } else {
       final int[] acceptableJavadocTokens = getAcceptableJavadocTokens();
       Arrays.sort(acceptableJavadocTokens);
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocBlockTagLocationCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocBlockTagLocationCheck.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.checks.javadoc;
 
+import static java.util.stream.Collectors.toUnmodifiableSet;
+
 import com.puppycrawl.tools.checkstyle.StatelessCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailNode;
 import com.puppycrawl.tools.checkstyle.api.JavadocTokenTypes;
@@ -26,7 +28,6 @@ import java.util.Arrays;
 import java.util.Set;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 
 /**
  * Checks that a <a
@@ -123,7 +124,7 @@ public class JavadocBlockTagLocationCheck extends AbstractJavadocCheck {
    * @since 8.24
    */
   public final void setTags(String... values) {
-    tags = Arrays.stream(values).collect(Collectors.toUnmodifiableSet());
+    tags = Arrays.stream(values).collect(toUnmodifiableSet());
   }
 
   /**
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocMethodCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocMethodCheck.java
@@ -19,6 +19,7 @@
 
 package com.puppycrawl.tools.checkstyle.checks.javadoc;
 
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.StatelessCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
@@ -219,7 +220,7 @@ public class JavadocMethodCheck extends AbstractCheck {
   private boolean allowMissingReturnTag;
 
   /** Specify annotations that allow missed documentation. */
-  private Set<String> allowedAnnotations = Set.of("Override");
+  private Set<String> allowedAnnotations = ImmutableSet.of("Override");
 
   /**
    * Setter to control whether to validate {@code throws} tags.
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocStyleCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocStyleCheck.java
@@ -257,8 +257,8 @@ public class JavadocStyleCheck extends AbstractCheck {
   }
 
   // suppress deprecation until https://github.com/checkstyle/checkstyle/issues/11166
-  @SuppressWarnings("deprecation")
   @Override
+  @SuppressWarnings("deprecation")
   public void visitToken(DetailAST ast) {
     if (shouldCheck(ast)) {
       final FileContents contents = getFileContents();
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocTagInfo.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocTagInfo.java
@@ -19,6 +19,10 @@
 
 package com.puppycrawl.tools.checkstyle.checks.javadoc;
 
+import static com.google.common.base.Preconditions.checkArgument;
+import static java.util.function.Function.identity;
+import static java.util.stream.Collectors.toUnmodifiableMap;
+
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.api.Scope;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
@@ -27,8 +31,6 @@ import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
 import java.util.Arrays;
 import java.util.BitSet;
 import java.util.Map;
-import java.util.function.Function;
-import java.util.stream.Collectors;
 
 /**
  * This enum defines the various Javadoc tags and their properties.
@@ -299,11 +301,9 @@ public enum JavadocTagInfo {
   static {
     final JavadocTagInfo[] values = values();
     TEXT_TO_TAG =
-        Arrays.stream(values)
-            .collect(Collectors.toUnmodifiableMap(JavadocTagInfo::getText, Function.identity()));
+        Arrays.stream(values).collect(toUnmodifiableMap(JavadocTagInfo::getText, identity()));
     NAME_TO_TAG =
-        Arrays.stream(values)
-            .collect(Collectors.toUnmodifiableMap(JavadocTagInfo::getName, Function.identity()));
+        Arrays.stream(values).collect(toUnmodifiableMap(JavadocTagInfo::getName, identity()));
   }
 
   /** The tag text. * */
@@ -376,15 +376,11 @@ public enum JavadocTagInfo {
    * @throws IllegalArgumentException if the text is not a valid tag
    */
   public static JavadocTagInfo fromText(final String text) {
-    if (text == null) {
-      throw new IllegalArgumentException("the text is null");
-    }
+    checkArgument(text != null, "the text is null");
 
     final JavadocTagInfo tag = TEXT_TO_TAG.get(text);
 
-    if (tag == null) {
-      throw new IllegalArgumentException("the text [" + text + "] is not a valid Javadoc tag text");
-    }
+    checkArgument(tag != null, "the text [%s] is not a valid Javadoc tag text", text);
 
     return tag;
   }
@@ -399,15 +395,11 @@ public enum JavadocTagInfo {
    *     {@link JavadocTagInfo#isValidName(String)}
    */
   public static JavadocTagInfo fromName(final String name) {
-    if (name == null) {
-      throw new IllegalArgumentException("the name is null");
-    }
+    checkArgument(name != null, "the name is null");
 
     final JavadocTagInfo tag = NAME_TO_TAG.get(name);
 
-    if (tag == null) {
-      throw new IllegalArgumentException("the name [" + name + "] is not a valid Javadoc tag name");
-    }
+    checkArgument(tag != null, "the name [%s] is not a valid Javadoc tag name", name);
 
     return tag;
   }
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocTypeCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocTypeCheck.java
@@ -19,6 +19,7 @@
 
 package com.puppycrawl.tools.checkstyle.checks.javadoc;
 
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.StatelessCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
@@ -160,7 +161,7 @@ public class JavadocTypeCheck extends AbstractCheck {
    * Specify annotations that allow skipping validation at all. Only short names are allowed, e.g.
    * {@code Generated}.
    */
-  private Set<String> allowedAnnotations = Set.of("Generated");
+  private Set<String> allowedAnnotations = ImmutableSet.of("Generated");
 
   /**
    * Setter to specify the visibility scope where Javadoc comments are checked.
@@ -256,8 +257,8 @@ public class JavadocTypeCheck extends AbstractCheck {
   }
 
   // suppress deprecation until https://github.com/checkstyle/checkstyle/issues/11166
-  @SuppressWarnings("deprecation")
   @Override
+  @SuppressWarnings("deprecation")
   public void visitToken(DetailAST ast) {
     if (shouldCheck(ast)) {
       final FileContents contents = getFileContents();
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocVariableCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocVariableCheck.java
@@ -126,8 +126,8 @@ public class JavadocVariableCheck extends AbstractCheck {
   }
 
   // suppress deprecation until https://github.com/checkstyle/checkstyle/issues/11166
-  @SuppressWarnings("deprecation")
   @Override
+  @SuppressWarnings("deprecation")
   public void visitToken(DetailAST ast) {
     if (shouldCheck(ast)) {
       final FileContents contents = getFileContents();
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/MissingJavadocMethodCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/MissingJavadocMethodCheck.java
@@ -19,6 +19,7 @@
 
 package com.puppycrawl.tools.checkstyle.checks.javadoc;
 
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
@@ -141,7 +142,7 @@ public class MissingJavadocMethodCheck extends AbstractCheck {
   private Pattern ignoreMethodNamesRegex;
 
   /** Configure annotations that allow missed documentation. */
-  private Set<String> allowedAnnotations = Set.of("Override");
+  private Set<String> allowedAnnotations = ImmutableSet.of("Override");
 
   /**
    * Setter to configure annotations that allow missed documentation.
@@ -225,8 +226,8 @@ public class MissingJavadocMethodCheck extends AbstractCheck {
   }
 
   // suppress deprecation until https://github.com/checkstyle/checkstyle/issues/11166
-  @SuppressWarnings("deprecation")
   @Override
+  @SuppressWarnings("deprecation")
   public final void visitToken(DetailAST ast) {
     final Scope theScope = ScopeUtil.getScope(ast);
     if (shouldCheck(ast, theScope)) {
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/MissingJavadocTypeCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/MissingJavadocTypeCheck.java
@@ -19,6 +19,7 @@
 
 package com.puppycrawl.tools.checkstyle.checks.javadoc;
 
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.StatelessCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
@@ -87,7 +88,7 @@ public class MissingJavadocTypeCheck extends AbstractCheck {
    * Specify annotations that allow missed documentation. If annotation is present in target sources
    * in multiple forms of qualified name, all forms should be listed in this property.
    */
-  private Set<String> skipAnnotations = Set.of("Generated");
+  private Set<String> skipAnnotations = ImmutableSet.of("Generated");
 
   /**
    * Setter to specify the visibility scope where Javadoc comments are checked.
@@ -143,8 +144,8 @@ public class MissingJavadocTypeCheck extends AbstractCheck {
   }
 
   // suppress deprecation until https://github.com/checkstyle/checkstyle/issues/11166
-  @SuppressWarnings("deprecation")
   @Override
+  @SuppressWarnings("deprecation")
   public void visitToken(DetailAST ast) {
     if (shouldCheck(ast)) {
       final FileContents contents = getFileContents();
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/SingleLineJavadocCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/SingleLineJavadocCheck.java
@@ -19,6 +19,7 @@
 
 package com.puppycrawl.tools.checkstyle.checks.javadoc;
 
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.StatelessCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.api.DetailNode;
@@ -70,7 +71,7 @@ public class SingleLineJavadocCheck extends AbstractJavadocCheck {
    * href="https://docs.oracle.com/javase/8/docs/technotes/tools/windows/javadoc.html#CHDBEFIF">
    * block tags</a> which are ignored by the check.
    */
-  private Set<String> ignoredTags = Set.of();
+  private Set<String> ignoredTags = ImmutableSet.of();
 
   /**
    * Control whether <a
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/WriteTagCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/WriteTagCheck.java
@@ -158,8 +158,8 @@ public class WriteTagCheck extends AbstractCheck {
   }
 
   // suppress deprecation until https://github.com/checkstyle/checkstyle/issues/11166
-  @SuppressWarnings("deprecation")
   @Override
+  @SuppressWarnings("deprecation")
   public void visitToken(DetailAST ast) {
     final FileContents contents = getFileContents();
     final int lineNo = ast.getLineNo();
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/utils/InlineTagUtil.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/javadoc/utils/InlineTagUtil.java
@@ -19,6 +19,10 @@
 
 package com.puppycrawl.tools.checkstyle.checks.javadoc.utils;
 
+import static com.google.common.base.Preconditions.checkArgument;
+import static java.util.regex.Pattern.DOTALL;
+import static java.util.regex.Pattern.MULTILINE;
+
 import com.puppycrawl.tools.checkstyle.api.LineColumn;
 import java.util.ArrayList;
 import java.util.List;
@@ -30,11 +34,10 @@ public final class InlineTagUtil {
 
   /** Inline tag pattern. */
   private static final Pattern INLINE_TAG_PATTERN =
-      Pattern.compile("\\{@(\\p{Alpha}+)\\b(.*?)}", Pattern.DOTALL);
+      Pattern.compile("\\{@(\\p{Alpha}+)\\b(.*?)}", DOTALL);
 
   /** Pattern to recognize leading "*" characters in Javadoc. */
-  private static final Pattern JAVADOC_PREFIX_PATTERN =
-      Pattern.compile("^\\s*\\*", Pattern.MULTILINE);
+  private static final Pattern JAVADOC_PREFIX_PATTERN = Pattern.compile("^\\s*\\*", MULTILINE);
 
   /** Pattern matching whitespace, used by {@link InlineTagUtil#collapseWhitespace(String)}. */
   private static final Pattern WHITESPACE_PATTERN = Pattern.compile("\\s+");
@@ -60,9 +63,9 @@ public final class InlineTagUtil {
    */
   public static List<TagInfo> extractInlineTags(String... lines) {
     for (String line : lines) {
-      if (line.indexOf(LINE_FEED) != -1 || line.indexOf(CARRIAGE_RETURN) != -1) {
-        throw new IllegalArgumentException("comment lines cannot contain newlines");
-      }
+      checkArgument(
+          line.indexOf(LINE_FEED) == -1 && line.indexOf(CARRIAGE_RETURN) == -1,
+          "comment lines cannot contain newlines");
     }
 
     final String commentText = convertLinesToString(lines);
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/metrics/AbstractClassCouplingCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/metrics/AbstractClassCouplingCheck.java
@@ -19,6 +19,11 @@
 
 package com.puppycrawl.tools.checkstyle.checks.metrics;
 
+import static com.google.common.base.Preconditions.checkArgument;
+import static java.util.function.Predicate.not;
+import static java.util.stream.Collectors.toUnmodifiableList;
+
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
@@ -29,7 +34,6 @@ import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
 import java.util.ArrayDeque;
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.Deque;
 import java.util.HashMap;
 import java.util.List;
@@ -37,9 +41,7 @@ import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
 import java.util.TreeSet;
-import java.util.function.Predicate;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 
 /** Base class for coupling calculation. */
 @FileStatefulCheck
@@ -124,7 +126,7 @@ public abstract class AbstractClassCouplingCheck extends AbstractCheck {
           "Stream");
 
   /** Package names to ignore. */
-  private static final Set<String> DEFAULT_EXCLUDED_PACKAGES = Collections.emptySet();
+  private static final Set<String> DEFAULT_EXCLUDED_PACKAGES = ImmutableSet.of();
 
   /** Pattern to match brackets in a full type name. */
   private static final Pattern BRACKET_PATTERN = Pattern.compile("\\[[^]]*]");
@@ -208,12 +210,12 @@ public abstract class AbstractClassCouplingCheck extends AbstractCheck {
   public final void setExcludedPackages(String... excludedPackages) {
     final List<String> invalidIdentifiers =
         Arrays.stream(excludedPackages)
-            .filter(Predicate.not(CommonUtil::isName))
-            .collect(Collectors.toUnmodifiableList());
-    if (!invalidIdentifiers.isEmpty()) {
-      throw new IllegalArgumentException(
-          "the following values are not valid identifiers: " + invalidIdentifiers);
-    }
+            .filter(not(CommonUtil::isName))
+            .collect(toUnmodifiableList());
+    checkArgument(
+        invalidIdentifiers.isEmpty(),
+        "the following values are not valid identifiers: %s",
+        invalidIdentifiers);
 
     this.excludedPackages = Set.of(excludedPackages);
   }
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/naming/AbbreviationAsWordInNameCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/naming/AbbreviationAsWordInNameCheck.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.checks.naming;
 
+import static java.util.stream.Collectors.toUnmodifiableSet;
+
 import com.puppycrawl.tools.checkstyle.StatelessCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
@@ -30,7 +32,6 @@ import java.util.HashSet;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 /**
  * Validates abbreviations (consecutive capital letters) length in identifier name, it also allows
@@ -199,8 +200,7 @@ public class AbbreviationAsWordInNameCheck extends AbstractCheck {
    */
   public void setAllowedAbbreviations(String... allowedAbbreviations) {
     if (allowedAbbreviations != null) {
-      this.allowedAbbreviations =
-          Arrays.stream(allowedAbbreviations).collect(Collectors.toUnmodifiableSet());
+      this.allowedAbbreviations = Arrays.stream(allowedAbbreviations).collect(toUnmodifiableSet());
     }
   }
 
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/naming/LambdaParameterNameCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/naming/LambdaParameterNameCheck.java
@@ -22,7 +22,6 @@ package com.puppycrawl.tools.checkstyle.checks.naming;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
-import java.util.Objects;
 
 /**
  * Checks lambda parameter names.
@@ -70,7 +69,7 @@ public class LambdaParameterNameCheck extends AbstractNameCheck {
   public void visitToken(DetailAST ast) {
     final boolean isInSwitchRule = ast.getParent().getType() == TokenTypes.SWITCH_RULE;
 
-    if (Objects.nonNull(ast.findFirstToken(TokenTypes.PARAMETERS))) {
+    if (ast.findFirstToken(TokenTypes.PARAMETERS) != null) {
       final DetailAST parametersNode = ast.findFirstToken(TokenTypes.PARAMETERS);
       TokenUtil.forEachChild(parametersNode, TokenTypes.PARAMETER_DEF, super::visitToken);
     } else if (!isInSwitchRule) {
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/regexp/DetectorOptions.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/regexp/DetectorOptions.java
@@ -19,6 +19,9 @@
 
 package com.puppycrawl.tools.checkstyle.checks.regexp;
 
+import static java.util.Objects.requireNonNullElse;
+import static java.util.regex.Pattern.CASE_INSENSITIVE;
+
 import com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter;
 import java.util.Optional;
 import java.util.regex.Pattern;
@@ -242,8 +245,8 @@ public final class DetectorOptions {
      * @return DetectorOptions instance.
      */
     public DetectorOptions build() {
-      message = Optional.ofNullable(message).orElse("");
-      suppressor = Optional.ofNullable(suppressor).orElse(NeverSuppress.INSTANCE);
+      message = requireNonNullElse(message, "");
+      suppressor = requireNonNullElse(suppressor, NeverSuppress.INSTANCE);
       pattern = Optional.ofNullable(format).map(this::createPattern).orElse(null);
       return DetectorOptions.this;
     }
@@ -257,7 +260,7 @@ public final class DetectorOptions {
     private Pattern createPattern(String formatValue) {
       int options = compileFlags;
       if (ignoreCase) {
-        options |= Pattern.CASE_INSENSITIVE;
+        options |= CASE_INSENSITIVE;
       }
       return Pattern.compile(formatValue, options);
     }
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/regexp/MultilineDetector.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/regexp/MultilineDetector.java
@@ -19,6 +19,7 @@
 
 package com.puppycrawl.tools.checkstyle.checks.regexp;
 
+import com.google.common.base.Strings;
 import com.puppycrawl.tools.checkstyle.api.FileText;
 import com.puppycrawl.tools.checkstyle.api.LineColumn;
 import java.util.regex.Matcher;
@@ -69,7 +70,7 @@ class MultilineDetector {
     resetState();
 
     final String format = options.getFormat();
-    if (format == null || format.isEmpty()) {
+    if (Strings.isNullOrEmpty(format)) {
       options.getReporter().log(1, MSG_EMPTY);
     } else {
       matcher = options.getPattern().matcher(fileText.getFullText());
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpCheck.java
@@ -19,6 +19,9 @@
 
 package com.puppycrawl.tools.checkstyle.checks.regexp;
 
+import static java.util.regex.Pattern.MULTILINE;
+
+import com.google.common.base.Strings;
 import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
@@ -151,7 +154,7 @@ public class RegexpCheck extends AbstractCheck {
   private int errorCount;
 
   /** Specify the pattern to match against. */
-  private Pattern format = Pattern.compile("^$", Pattern.MULTILINE);
+  private Pattern format = Pattern.compile("^$", MULTILINE);
 
   /** The matcher. */
   private Matcher matcher;
@@ -218,7 +221,7 @@ public class RegexpCheck extends AbstractCheck {
    * @since 4.0
    */
   public final void setFormat(Pattern pattern) {
-    format = CommonUtil.createPattern(pattern.pattern(), Pattern.MULTILINE);
+    format = CommonUtil.createPattern(pattern.pattern(), MULTILINE);
   }
 
   @Override
@@ -237,8 +240,8 @@ public class RegexpCheck extends AbstractCheck {
   }
 
   // suppress deprecation until https://github.com/checkstyle/checkstyle/issues/11166
-  @SuppressWarnings("deprecation")
   @Override
+  @SuppressWarnings("deprecation")
   public void beginTree(DetailAST rootAST) {
     matcher = format.matcher(getFileContents().getText().getFullText());
     matchCount = 0;
@@ -336,7 +339,7 @@ public class RegexpCheck extends AbstractCheck {
   private String getMessage() {
     String msg;
 
-    if (message == null || message.isEmpty()) {
+    if (Strings.isNullOrEmpty(message)) {
       msg = format.pattern();
     } else {
       msg = message;
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpMultilineCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpMultilineCheck.java
@@ -19,13 +19,15 @@
 
 package com.puppycrawl.tools.checkstyle.checks.regexp;
 
+import static java.util.regex.Pattern.DOTALL;
+import static java.util.regex.Pattern.MULTILINE;
+
 import com.puppycrawl.tools.checkstyle.PropertyType;
 import com.puppycrawl.tools.checkstyle.StatelessCheck;
 import com.puppycrawl.tools.checkstyle.XdocsPropertyType;
 import com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck;
 import com.puppycrawl.tools.checkstyle.api.FileText;
 import java.io.File;
-import java.util.regex.Pattern;
 
 /**
  * Checks that a specified pattern matches across multiple lines in any file type.
@@ -121,9 +123,9 @@ public class RegexpMultilineCheck extends AbstractFileSetCheck {
     final int result;
 
     if (matchAcrossLines) {
-      result = Pattern.DOTALL;
+      result = DOTALL;
     } else {
-      result = Pattern.MULTILINE;
+      result = MULTILINE;
     }
 
     return result;
--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpSinglelineJavaCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpSinglelineJavaCheck.java
@@ -102,8 +102,8 @@ public class RegexpSinglelineJavaCheck extends AbstractCheck {
   }
 
   // suppress deprecation until https://github.com/checkstyle/checkstyle/issues/11166
-  @SuppressWarnings("deprecation")
   @Override
+  @SuppressWarnings("deprecation")
   public void beginTree(DetailAST rootAST) {
     MatchSuppressor suppressor = null;
     if (ignoreComments) {
--- a/src/main/java/com/puppycrawl/tools/checkstyle/filters/SuppressWithPlainTextCommentFilter.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/filters/SuppressWithPlainTextCommentFilter.java
@@ -356,7 +356,7 @@ public class SuppressWithPlainTextCommentFilter extends AbstractAutomaticBean im
       }
       final Suppression suppression = (Suppression) other;
       return Objects.equals(lineNo, suppression.lineNo)
-          && Objects.equals(suppressionType, suppression.suppressionType)
+          && suppressionType == suppression.suppressionType
           && Objects.equals(eventSourceRegexp, suppression.eventSourceRegexp)
           && Objects.equals(eventMessageRegexp, suppression.eventMessageRegexp)
           && Objects.equals(eventIdRegexp, suppression.eventIdRegexp);
--- a/src/main/java/com/puppycrawl/tools/checkstyle/filters/SuppressionCommentFilter.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/filters/SuppressionCommentFilter.java
@@ -483,7 +483,7 @@ public class SuppressionCommentFilter extends AbstractAutomaticBean implements T
       final Tag tag = (Tag) other;
       return Objects.equals(line, tag.line)
           && Objects.equals(column, tag.column)
-          && Objects.equals(tagType, tag.tagType)
+          && tagType == tag.tagType
           && Objects.equals(text, tag.text)
           && Objects.equals(tagCheckRegexp, tag.tagCheckRegexp)
           && Objects.equals(tagMessageRegexp, tag.tagMessageRegexp)
--- a/src/main/java/com/puppycrawl/tools/checkstyle/filters/SuppressionXpathFilter.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/filters/SuppressionXpathFilter.java
@@ -19,13 +19,13 @@
 
 package com.puppycrawl.tools.checkstyle.filters;
 
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.AbstractAutomaticBean;
 import com.puppycrawl.tools.checkstyle.TreeWalkerAuditEvent;
 import com.puppycrawl.tools.checkstyle.TreeWalkerFilter;
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
 import com.puppycrawl.tools.checkstyle.api.ExternalResourceHolder;
 import com.puppycrawl.tools.checkstyle.utils.FilterUtil;
-import java.util.Collections;
 import java.util.HashSet;
 import java.util.Objects;
 import java.util.Set;
@@ -186,7 +186,7 @@ public class SuppressionXpathFilter extends AbstractAutomaticBean
 
   @Override
   public Set<String> getExternalResourceLocations() {
-    return Collections.singleton(file);
+    return ImmutableSet.of(file);
   }
 
   @Override
--- a/src/main/java/com/puppycrawl/tools/checkstyle/filters/XpathFilterElement.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/filters/XpathFilterElement.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.filters;
 
+import static java.util.stream.Collectors.toUnmodifiableList;
+
 import com.puppycrawl.tools.checkstyle.TreeWalkerAuditEvent;
 import com.puppycrawl.tools.checkstyle.TreeWalkerFilter;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
@@ -28,7 +30,6 @@ import java.util.List;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 import net.sf.saxon.Configuration;
 import net.sf.saxon.om.Item;
 import net.sf.saxon.sxpath.XPathDynamicContext;
@@ -163,9 +164,7 @@ public class XpathFilterElement implements TreeWalkerFilter {
     } else {
       isMatching = false;
       final List<AbstractNode> nodes =
-          getItems(event).stream()
-              .map(AbstractNode.class::cast)
-              .collect(Collectors.toUnmodifiableList());
+          getItems(event).stream().map(AbstractNode.class::cast).collect(toUnmodifiableList());
       for (AbstractNode abstractNode : nodes) {
         isMatching =
             abstractNode.getTokenType() == event.getTokenType()
--- a/src/main/java/com/puppycrawl/tools/checkstyle/gui/TreeTable.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/gui/TreeTable.java
@@ -19,6 +19,9 @@
 
 package com.puppycrawl.tools.checkstyle.gui;
 
+import static java.util.stream.Collectors.joining;
+import static java.util.stream.Collectors.toCollection;
+
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.utils.XpathUtil;
 import com.puppycrawl.tools.checkstyle.xpath.ElementNode;
@@ -36,7 +39,6 @@ import java.util.Collection;
 import java.util.Deque;
 import java.util.EventObject;
 import java.util.List;
-import java.util.stream.Collectors;
 import javax.swing.AbstractAction;
 import javax.swing.Action;
 import javax.swing.JTable;
@@ -203,7 +205,7 @@ public final class TreeTable extends JTable {
             XpathUtil.getXpathItems(xpath, new RootNode(rootAST)).stream()
                 .map(ElementNode.class::cast)
                 .map(ElementNode::getUnderlyingNode)
-                .collect(Collectors.toCollection(ArrayDeque::new));
+                .collect(toCollection(ArrayDeque::new));
         updateTreeTable(xpath, nodes);
       } catch (XPathException exception) {
         xpathEditor.setText(xpathEditor.getText() + NEWLINE + exception.getMessage());
@@ -254,7 +256,7 @@ public final class TreeTable extends JTable {
   private static String getAllMatchingXpathQueriesText(Deque<DetailAST> nodes) {
     return nodes.stream()
         .map(XpathQueryGenerator::generateXpathQuery)
-        .collect(Collectors.joining(NEWLINE, "", NEWLINE));
+        .collect(joining(NEWLINE, "", NEWLINE));
   }
 
   /**
--- a/src/main/java/com/puppycrawl/tools/checkstyle/meta/JavadocMetadataScraper.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/meta/JavadocMetadataScraper.java
@@ -19,6 +19,10 @@
 
 package com.puppycrawl.tools.checkstyle.meta;
 
+import static java.util.Collections.unmodifiableMap;
+import static java.util.stream.Collectors.joining;
+
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.api.DetailNode;
@@ -28,7 +32,6 @@ import com.puppycrawl.tools.checkstyle.checks.javadoc.AbstractJavadocCheck;
 import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
 import java.util.ArrayDeque;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.Deque;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -39,7 +42,6 @@ import java.util.Optional;
 import java.util.Set;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 import javax.xml.parsers.ParserConfigurationException;
 import javax.xml.transform.TransformerException;
 
@@ -98,7 +100,7 @@ public class JavadocMetadataScraper extends AbstractJavadocCheck {
    * files.
    */
   private static final Set<String> PROPERTIES_TO_NOT_WRITE =
-      Set.of(
+      ImmutableSet.of(
           "null",
           "the charset property of the parent <a href=https://checkstyle.org/"
               + "config.html#Checker>Checker</a> module");
@@ -477,7 +479,7 @@ public class JavadocMetadataScraper extends AbstractJavadocCheck {
     return Arrays.stream(parentNode.getChildren())
         .filter(child -> child.getType() == JavadocTokenTypes.TEXT)
         .map(node -> QUOTE_PATTERN.matcher(node.getText().trim()).replaceAll(""))
-        .collect(Collectors.joining(" "));
+        .collect(joining(" "));
   }
 
   /**
@@ -594,7 +596,7 @@ public class JavadocMetadataScraper extends AbstractJavadocCheck {
    * @return map containing module details of supplied checks.
    */
   public static Map<String, ModuleDetails> getModuleDetailsStore() {
-    return Collections.unmodifiableMap(MODULE_DETAILS_STORE);
+    return unmodifiableMap(MODULE_DETAILS_STORE);
   }
 
   /** Reset the module detail store of any previous information. */
@@ -673,7 +675,7 @@ public class JavadocMetadataScraper extends AbstractJavadocCheck {
     return getFirstChildOfType(ast, JavadocTokenTypes.TEXT, 0)
         .map(DetailNode::getText)
         .map(pattern::matcher)
-        .map(Matcher::matches)
-        .orElse(Boolean.FALSE);
+        .filter(Matcher::matches)
+        .isPresent();
   }
 }
--- a/src/main/java/com/puppycrawl/tools/checkstyle/meta/MetadataGeneratorUtil.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/meta/MetadataGeneratorUtil.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.meta;
 
+import static java.util.stream.Collectors.toUnmodifiableList;
+
 import com.puppycrawl.tools.checkstyle.AbstractAutomaticBean.OutputStreamOptions;
 import com.puppycrawl.tools.checkstyle.Checker;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
@@ -34,7 +36,6 @@ import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.ArrayList;
 import java.util.List;
-import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 /** Class which handles all the metadata generation and writing calls. */
@@ -98,7 +99,7 @@ public final class MetadataGeneratorUtil {
                           || fileName.endsWith("Check.java")
                           || fileName.endsWith("Filter.java");
                     })
-                .collect(Collectors.toUnmodifiableList()));
+                .collect(toUnmodifiableList()));
       }
     }
 
--- a/src/main/java/com/puppycrawl/tools/checkstyle/meta/ModuleDetails.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/meta/ModuleDetails.java
@@ -19,8 +19,9 @@
 
 package com.puppycrawl.tools.checkstyle.meta;
 
+import static java.util.Collections.unmodifiableList;
+
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 
 /** Simple POJO class for module details. */
@@ -125,7 +126,7 @@ public final class ModuleDetails {
    * @return property list of module
    */
   public List<ModulePropertyDetails> getProperties() {
-    return Collections.unmodifiableList(properties);
+    return unmodifiableList(properties);
   }
 
   /**
@@ -152,7 +153,7 @@ public final class ModuleDetails {
    * @return violation message keys of module
    */
   public List<String> getViolationMessageKeys() {
-    return Collections.unmodifiableList(violationMessageKeys);
+    return unmodifiableList(violationMessageKeys);
   }
 
   /**
--- a/src/main/java/com/puppycrawl/tools/checkstyle/site/ClassAndPropertiesSettersJavadocScraper.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/site/ClassAndPropertiesSettersJavadocScraper.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.site;
 
+import static java.util.Collections.unmodifiableMap;
+
 import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.api.DetailNode;
@@ -27,7 +29,6 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.checks.javadoc.AbstractJavadocCheck;
 import com.puppycrawl.tools.checkstyle.utils.BlockCommentPosition;
 import java.beans.Introspector;
-import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.Map;
 import java.util.regex.Pattern;
@@ -65,7 +66,7 @@ public class ClassAndPropertiesSettersJavadocScraper extends AbstractJavadocChec
    * @return the javadocs.
    */
   public static Map<String, DetailNode> getJavadocsForModuleOrProperty() {
-    return Collections.unmodifiableMap(JAVADOC_FOR_MODULE_OR_PROPERTY);
+    return unmodifiableMap(JAVADOC_FOR_MODULE_OR_PROPERTY);
   }
 
   @Override
--- a/src/main/java/com/puppycrawl/tools/checkstyle/site/ExampleMacro.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/site/ExampleMacro.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.site;
 
+import static java.util.stream.Collectors.joining;
+
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -26,7 +28,6 @@ import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
 import java.util.Locale;
-import java.util.stream.Collectors;
 import org.apache.maven.doxia.macro.AbstractMacro;
 import org.apache.maven.doxia.macro.Macro;
 import org.apache.maven.doxia.macro.MacroExecutionException;
@@ -121,7 +122,7 @@ public class ExampleMacro extends AbstractMacro {
         .dropWhile(line -> !XML_CONFIG_START.equals(line))
         .skip(1)
         .takeWhile(line -> !XML_CONFIG_END.equals(line))
-        .collect(Collectors.joining(NEWLINE));
+        .collect(joining(NEWLINE));
   }
 
   /**
@@ -136,7 +137,7 @@ public class ExampleMacro extends AbstractMacro {
         .dropWhile(line -> !line.contains(CODE_SNIPPET_START))
         .skip(1)
         .takeWhile(line -> !line.contains(CODE_SNIPPET_END))
-        .collect(Collectors.joining(NEWLINE));
+        .collect(joining(NEWLINE));
   }
 
   /**
--- a/src/main/java/com/puppycrawl/tools/checkstyle/site/PropertiesMacro.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/site/PropertiesMacro.java
@@ -19,6 +19,10 @@
 
 package com.puppycrawl.tools.checkstyle.site;
 
+import static java.util.Collections.unmodifiableSet;
+import static java.util.stream.Collectors.toUnmodifiableList;
+
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.PropertyType;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailNode;
@@ -29,14 +33,12 @@ import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
 import java.io.File;
 import java.lang.reflect.Field;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 import org.apache.maven.doxia.macro.AbstractMacro;
 import org.apache.maven.doxia.macro.Macro;
 import org.apache.maven.doxia.macro.MacroExecutionException;
@@ -54,16 +56,15 @@ public class PropertiesMacro extends AbstractMacro {
 
   /** Set of properties not inherited from the base token configuration. */
   public static final Set<String> NON_BASE_TOKEN_PROPERTIES =
-      Collections.unmodifiableSet(
-          Arrays.stream(
-                  new String[] {
-                    "AtclauseOrder - target",
-                    "DescendantToken - limitedTokens",
-                    "IllegalType - memberModifiers",
-                    "MagicNumber - constantWaiverParentToken",
-                    "MultipleStringLiterals - ignoreOccurrenceContext",
-                  })
-              .collect(Collectors.toSet()));
+      unmodifiableSet(
+          ImmutableSet.copyOf(
+              new String[] {
+                "AtclauseOrder - target",
+                "DescendantToken - limitedTokens",
+                "IllegalType - memberModifiers",
+                "MagicNumber - constantWaiverParentToken",
+                "MultipleStringLiterals - ignoreOccurrenceContext",
+              }));
 
   /** The precompiled pattern for a comma followed by a space. */
   private static final Pattern COMMA_SPACE_PATTERN = Pattern.compile(", ");
@@ -334,7 +335,7 @@ public class PropertiesMacro extends AbstractMacro {
         final List<String> configurableTokens =
             SiteUtil.getDifference(check.getAcceptableTokens(), check.getRequiredTokens()).stream()
                 .map(TokenUtil::getTokenName)
-                .collect(Collectors.toUnmodifiableList());
+                .collect(toUnmodifiableList());
         sink.text("subset of tokens");
 
         writeTokensList(sink, configurableTokens, SiteUtil.PATH_TO_TOKEN_TYPES, true);
@@ -346,7 +347,7 @@ public class PropertiesMacro extends AbstractMacro {
                   check.getAcceptableJavadocTokens(), check.getRequiredJavadocTokens())
               .stream()
               .map(JavadocUtil::getTokenName)
-              .collect(Collectors.toUnmodifiableList());
+              .collect(toUnmodifiableList());
       sink.text("subset of javadoc tokens");
       writeTokensList(sink, configurableTokens, SiteUtil.PATH_TO_JAVADOC_TOKEN_TYPES, true);
     } else {
@@ -473,7 +474,7 @@ public class PropertiesMacro extends AbstractMacro {
         final List<String> configurableTokens =
             SiteUtil.getDifference(check.getDefaultTokens(), check.getRequiredTokens()).stream()
                 .map(TokenUtil::getTokenName)
-                .collect(Collectors.toUnmodifiableList());
+                .collect(toUnmodifiableList());
         writeTokensList(sink, configurableTokens, SiteUtil.PATH_TO_TOKEN_TYPES, true);
       }
     } else if (SiteUtil.JAVADOC_TOKENS.equals(propertyName)) {
@@ -482,7 +483,7 @@ public class PropertiesMacro extends AbstractMacro {
           SiteUtil.getDifference(check.getDefaultJavadocTokens(), check.getRequiredJavadocTokens())
               .stream()
               .map(JavadocUtil::getTokenName)
-              .collect(Collectors.toUnmodifiableList());
+              .collect(toUnmodifiableList());
       writeTokensList(sink, configurableTokens, SiteUtil.PATH_TO_JAVADOC_TOKEN_TYPES, true);
     } else {
       final String defaultValue = getDefaultValue(propertyName, field, instance);
--- a/src/main/java/com/puppycrawl/tools/checkstyle/site/SiteUtil.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/site/SiteUtil.java
@@ -19,6 +19,14 @@
 
 package com.puppycrawl.tools.checkstyle.site;
 
+import static java.util.stream.Collectors.joining;
+import static java.util.stream.Collectors.toCollection;
+import static java.util.stream.Collectors.toUnmodifiableList;
+import static java.util.stream.Collectors.toUnmodifiableSet;
+
+import com.google.common.base.Strings;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Lists;
 import com.puppycrawl.tools.checkstyle.Checker;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
@@ -72,7 +80,6 @@ import java.util.Optional;
 import java.util.Set;
 import java.util.TreeSet;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 import java.util.stream.Stream;
 import javax.annotation.Nullable;
@@ -156,7 +163,7 @@ public final class SiteUtil {
 
   /** Set of properties that are undocumented. Those are internal properties. */
   private static final Set<String> UNDOCUMENTED_PROPERTIES =
-      Set.of(
+      ImmutableSet.of(
           "SuppressWithNearbyCommentFilter.fileContents", "SuppressionCommentFilter.fileContents");
 
   /** Properties that can not be gathered from class instance. */
@@ -480,7 +487,7 @@ public final class SiteUtil {
             (path, attr) -> {
               return attr.isRegularFile() && path.toString().endsWith(".xml.template");
             })) {
-      return stream.collect(Collectors.toUnmodifiableSet());
+      return stream.collect(toUnmodifiableSet());
     } catch (IOException ioException) {
       throw new MacroExecutionException("Failed to find xdocs templates", ioException);
     }
@@ -507,7 +514,7 @@ public final class SiteUtil {
     }
 
     // If parent class is not found, check interfaces
-    if (parentModuleName == null || parentModuleName.isEmpty()) {
+    if (Strings.isNullOrEmpty(parentModuleName)) {
       final Class<?>[] interfaces = moduleClass.getInterfaces();
       for (Class<?> interfaceClass : interfaces) {
         parentModuleName = CLASS_TO_PARENT_MODULE.get(interfaceClass);
@@ -517,7 +524,7 @@ public final class SiteUtil {
       }
     }
 
-    if (parentModuleName == null || parentModuleName.isEmpty()) {
+    if (Strings.isNullOrEmpty(parentModuleName)) {
       final String message =
           String.format(
               Locale.ROOT, "Failed to find parent module for %s", moduleClass.getSimpleName());
@@ -545,7 +552,7 @@ public final class SiteUtil {
                 prop -> {
                   return !isGlobalProperty(clss, prop) && !isUndocumentedProperty(clss, prop);
                 })
-            .collect(Collectors.toCollection(HashSet::new));
+            .collect(toCollection(HashSet::new));
     properties.addAll(getNonExplicitProperties(instance, clss));
     return new TreeSet<>(properties);
   }
@@ -664,7 +671,7 @@ public final class SiteUtil {
     treeWalkerConfig.addChild(scraperCheckConfig);
     try {
       checker.configure(defaultConfiguration);
-      final List<File> filesToProcess = List.of(moduleFile);
+      final List<File> filesToProcess = ImmutableList.of(moduleFile);
       checker.process(filesToProcess);
       checker.destroy();
     } catch (CheckstyleException checkstyleException) {
@@ -987,9 +994,7 @@ public final class SiteUtil {
     if (value != null && Array.getLength(value) > 0) {
       result =
           removeSquareBrackets(
-              Arrays.stream((Pattern[]) value)
-                  .map(Pattern::pattern)
-                  .collect(Collectors.joining(COMMA_SPACE)));
+              Arrays.stream((Pattern[]) value).map(Pattern::pattern).collect(joining(COMMA_SPACE)));
     }
 
     if (result.isEmpty()) {
@@ -1021,8 +1026,7 @@ public final class SiteUtil {
       result = "";
     } else {
       try (Stream<?> valuesStream = getValuesStream(value)) {
-        result =
-            valuesStream.map(String.class::cast).sorted().collect(Collectors.joining(COMMA_SPACE));
+        result = valuesStream.map(String.class::cast).sorted().collect(joining(COMMA_SPACE));
       }
     }
 
@@ -1063,10 +1067,7 @@ public final class SiteUtil {
   private static String getIntArrayPropertyValue(Object value) {
     try (IntStream stream = getIntStream(value)) {
       String result =
-          stream
-              .mapToObj(TokenUtil::getTokenName)
-              .sorted()
-              .collect(Collectors.joining(COMMA_SPACE));
+          stream.mapToObj(TokenUtil::getTokenName).sorted().collect(joining(COMMA_SPACE));
       if (result.isEmpty()) {
         result = CURLY_BRACKETS;
       }
@@ -1172,11 +1173,11 @@ public final class SiteUtil {
    */
   public static List<Integer> getDifference(int[] tokens, int... subtractions) {
     final Set<Integer> subtractionsSet =
-        Arrays.stream(subtractions).boxed().collect(Collectors.toUnmodifiableSet());
+        Arrays.stream(subtractions).boxed().collect(toUnmodifiableSet());
     return Arrays.stream(tokens)
         .boxed()
         .filter(token -> !subtractionsSet.contains(token))
-        .collect(Collectors.toUnmodifiableList());
+        .collect(toUnmodifiableList());
   }
 
   /**
--- a/src/main/java/com/puppycrawl/tools/checkstyle/site/XdocsTemplateParser.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/site/XdocsTemplateParser.java
@@ -19,6 +19,7 @@
 
 package com.puppycrawl.tools.checkstyle.site;
 
+import com.google.common.base.Strings;
 import java.io.File;
 import java.io.IOException;
 import java.io.Reader;
@@ -119,7 +120,7 @@ public class XdocsTemplateParser extends XdocParser {
   private void processMacroStart(XmlPullParser parser) throws MacroExecutionException {
     macroName = parser.getAttributeValue(null, Attribute.NAME.toString());
 
-    if (macroName == null || macroName.isEmpty()) {
+    if (Strings.isNullOrEmpty(macroName)) {
       final String message =
           String.format(
               Locale.ROOT,
@@ -138,7 +139,7 @@ public class XdocsTemplateParser extends XdocParser {
    * @throws MacroExecutionException if the parameter name or value is not specified.
    */
   private void processParamStart(XmlPullParser parser, Sink sink) throws MacroExecutionException {
-    if (macroName != null && !macroName.isEmpty()) {
+    if (!Strings.isNullOrEmpty(macroName)) {
       final String paramName = parser.getAttributeValue(null, Attribute.NAME.toString());
       final String paramValue = parser.getAttributeValue(null, Attribute.VALUE.toString());
 
--- a/src/main/java/com/puppycrawl/tools/checkstyle/utils/AnnotationUtil.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/utils/AnnotationUtil.java
@@ -19,6 +19,9 @@
 
 package com.puppycrawl.tools.checkstyle.utils;
 
+import static com.google.common.base.Preconditions.checkArgument;
+
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.api.FullIdent;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
@@ -38,7 +41,7 @@ public final class AnnotationUtil {
   private static final String FQ_OVERRIDE = "java.lang." + OVERRIDE;
 
   /** Simple and fully-qualified {@link Override Override} annotation names. */
-  private static final Set<String> OVERRIDE_ANNOTATIONS = Set.of(OVERRIDE, FQ_OVERRIDE);
+  private static final Set<String> OVERRIDE_ANNOTATIONS = ImmutableSet.of(OVERRIDE, FQ_OVERRIDE);
 
   /**
    * Private utility constructor.
@@ -92,9 +95,7 @@ public final class AnnotationUtil {
    * @throws IllegalArgumentException when ast or annotations are null
    */
   public static boolean containsAnnotation(DetailAST ast, Set<String> annotations) {
-    if (annotations == null) {
-      throw new IllegalArgumentException("annotations cannot be null");
-    }
+    checkArgument(annotations != null, "annotations cannot be null");
     boolean result = false;
     if (!annotations.isEmpty()) {
       final DetailAST firstMatchingAnnotation =
@@ -150,9 +151,7 @@ public final class AnnotationUtil {
    * @throws IllegalArgumentException when ast is null
    */
   public static DetailAST getAnnotationHolder(DetailAST ast) {
-    if (ast == null) {
-      throw new IllegalArgumentException(THE_AST_IS_NULL);
-    }
+    checkArgument(ast != null, THE_AST_IS_NULL);
 
     final DetailAST annotationHolder;
 
@@ -182,17 +181,11 @@ public final class AnnotationUtil {
    * @throws IllegalArgumentException when ast or annotations are null; when annotation is blank
    */
   public static DetailAST getAnnotation(final DetailAST ast, String annotation) {
-    if (ast == null) {
-      throw new IllegalArgumentException(THE_AST_IS_NULL);
-    }
+    checkArgument(ast != null, THE_AST_IS_NULL);
 
-    if (annotation == null) {
-      throw new IllegalArgumentException("the annotation is null");
-    }
+    checkArgument(annotation != null, "the annotation is null");
 
-    if (CommonUtil.isBlank(annotation)) {
-      throw new IllegalArgumentException("the annotation is empty or spaces");
-    }
+    checkArgument(!CommonUtil.isBlank(annotation), "the annotation is empty or spaces");
 
     return findFirstAnnotation(
         ast,
--- a/src/main/java/com/puppycrawl/tools/checkstyle/utils/CheckUtil.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/utils/CheckUtil.java
@@ -19,6 +19,11 @@
 
 package com.puppycrawl.tools.checkstyle.utils;
 
+import static com.google.common.base.Preconditions.checkArgument;
+import static java.util.function.Predicate.not;
+import static java.util.stream.Collectors.joining;
+import static java.util.stream.Collectors.toUnmodifiableSet;
+
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.api.FullIdent;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
@@ -29,9 +34,7 @@ import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
 import java.util.Set;
-import java.util.function.Predicate;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 /** Contains utility methods for the checks. */
@@ -315,9 +318,7 @@ public final class CheckUtil {
    */
   private static AccessModifierOption getAccessModifierFromModifiersTokenDirectly(
       DetailAST modifiersToken) {
-    if (modifiersToken == null) {
-      throw new IllegalArgumentException("expected non-null AST-token with type 'MODIFIERS'");
-    }
+    checkArgument(modifiersToken != null, "expected non-null AST-token with type 'MODIFIERS'");
 
     AccessModifierOption accessModifier = AccessModifierOption.PACKAGE;
     for (DetailAST token = modifiersToken.getFirstChild();
@@ -369,8 +370,8 @@ public final class CheckUtil {
   public static Set<String> parseClassNames(String... classNames) {
     return Arrays.stream(classNames)
         .flatMap(className -> Stream.of(className, CommonUtil.baseClassName(className)))
-        .filter(Predicate.not(String::isEmpty))
-        .collect(Collectors.toUnmodifiableSet());
+        .filter(not(String::isEmpty))
+        .collect(toUnmodifiableSet());
   }
 
   /**
@@ -391,7 +392,7 @@ public final class CheckUtil {
 
     return lines.stream()
         .map(line -> stripIndentAndTrailingWhitespaceFromLine(line, indent))
-        .collect(Collectors.joining(System.lineSeparator(), suffix, suffix));
+        .collect(joining(System.lineSeparator(), suffix, suffix));
   }
 
   /**
--- a/src/main/java/com/puppycrawl/tools/checkstyle/utils/CommonUtil.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/utils/CommonUtil.java
@@ -32,7 +32,6 @@ import java.net.URL;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.BitSet;
-import java.util.Objects;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.regex.PatternSyntaxException;
@@ -506,7 +505,7 @@ public final class CommonUtil {
    * @return true if the arg is blank.
    */
   public static boolean isBlank(String value) {
-    return Objects.isNull(value) || indexOfNonWhitespace(value) >= value.length();
+    return value == null || indexOfNonWhitespace(value) >= value.length();
   }
 
   /**
--- a/src/main/java/com/puppycrawl/tools/checkstyle/utils/JavadocUtil.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/utils/JavadocUtil.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.utils;
 
+import static com.google.common.base.Preconditions.checkArgument;
+
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.api.DetailNode;
 import com.puppycrawl.tools.checkstyle.api.JavadocTokenTypes;
@@ -262,9 +264,7 @@ public final class JavadocUtil {
    */
   public static String getTokenName(int id) {
     final String name = TOKEN_VALUE_TO_NAME.get(id);
-    if (name == null) {
-      throw new IllegalArgumentException(UNKNOWN_JAVADOC_TOKEN_ID_EXCEPTION_MESSAGE + id);
-    }
+    checkArgument(name != null, "%s%s", UNKNOWN_JAVADOC_TOKEN_ID_EXCEPTION_MESSAGE, id);
     return name;
   }
 
@@ -277,9 +277,7 @@ public final class JavadocUtil {
    */
   public static int getTokenId(String name) {
     final Integer id = TOKEN_NAME_TO_VALUE.get(name);
-    if (id == null) {
-      throw new IllegalArgumentException("Unknown javadoc token name. Given name " + name);
-    }
+    checkArgument(id != null, "Unknown javadoc token name. Given name %s", name);
     return id;
   }
 
--- a/src/main/java/com/puppycrawl/tools/checkstyle/utils/ModuleReflectionUtil.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/utils/ModuleReflectionUtil.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.utils;
 
+import static java.util.stream.Collectors.toUnmodifiableSet;
+
 import com.google.common.reflect.ClassPath;
 import com.puppycrawl.tools.checkstyle.AbstractAutomaticBean;
 import com.puppycrawl.tools.checkstyle.TreeWalkerFilter;
@@ -33,7 +35,6 @@ import java.lang.reflect.Constructor;
 import java.lang.reflect.Modifier;
 import java.util.Collection;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 /** Contains utility methods for module reflection. */
 public final class ModuleReflectionUtil {
@@ -57,7 +58,7 @@ public final class ModuleReflectionUtil {
         .flatMap(pkg -> classPath.getTopLevelClasses(pkg).stream())
         .map(ClassPath.ClassInfo::load)
         .filter(ModuleReflectionUtil::isCheckstyleModule)
-        .collect(Collectors.toUnmodifiableSet());
+        .collect(toUnmodifiableSet());
   }
 
   /**
--- a/src/main/java/com/puppycrawl/tools/checkstyle/utils/ScopeUtil.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/utils/ScopeUtil.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.utils;
 
+import static java.util.Objects.requireNonNullElseGet;
+
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.api.Scope;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
@@ -78,8 +80,7 @@ public final class ScopeUtil {
    * @see #getDefaultScope(DetailAST)
    */
   public static Scope getScopeFromMods(DetailAST aMods) {
-    return Optional.ofNullable(getDeclaredScopeFromMods(aMods))
-        .orElseGet(() -> getDefaultScope(aMods));
+    return requireNonNullElseGet(getDeclaredScopeFromMods(aMods), () -> getDefaultScope(aMods));
   }
 
   /**
--- a/src/main/java/com/puppycrawl/tools/checkstyle/utils/TokenUtil.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/utils/TokenUtil.java
@@ -19,6 +19,10 @@
 
 package com.puppycrawl.tools.checkstyle.utils;
 
+import static com.google.common.base.Preconditions.checkArgument;
+import static java.util.function.Predicate.not;
+import static java.util.stream.Collectors.toUnmodifiableMap;
+
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import java.lang.reflect.Field;
@@ -31,7 +35,6 @@ import java.util.Optional;
 import java.util.ResourceBundle;
 import java.util.function.Consumer;
 import java.util.function.Predicate;
-import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
 /** Contains utility methods for tokens. */
@@ -91,7 +94,7 @@ public final class TokenUtil {
   public static Map<String, Integer> nameToValueMapFromPublicIntFields(Class<?> cls) {
     return Arrays.stream(cls.getDeclaredFields())
         .filter(fld -> Modifier.isPublic(fld.getModifiers()) && fld.getType() == Integer.TYPE)
-        .collect(Collectors.toUnmodifiableMap(Field::getName, fld -> getIntFromField(fld, null)));
+        .collect(toUnmodifiableMap(Field::getName, fld -> getIntFromField(fld, null)));
   }
 
   /**
@@ -102,7 +105,7 @@ public final class TokenUtil {
    */
   public static Map<Integer, String> invertMap(Map<String, Integer> map) {
     return map.entrySet().stream()
-        .collect(Collectors.toUnmodifiableMap(Map.Entry::getValue, Map.Entry::getKey));
+        .collect(toUnmodifiableMap(Map.Entry::getValue, Map.Entry::getKey));
   }
 
   /**
@@ -134,9 +137,7 @@ public final class TokenUtil {
    */
   public static String getTokenName(int id) {
     final String name = TOKEN_VALUE_TO_NAME.get(id);
-    if (name == null) {
-      throw new IllegalArgumentException(String.format(Locale.ROOT, TOKEN_ID_EXCEPTION_FORMAT, id));
-    }
+    checkArgument(name != null, String.format(Locale.ROOT, TOKEN_ID_EXCEPTION_FORMAT, id));
     return name;
   }
 
@@ -149,10 +150,7 @@ public final class TokenUtil {
    */
   public static int getTokenId(String name) {
     final Integer id = TOKEN_NAME_TO_VALUE.get(name);
-    if (id == null) {
-      throw new IllegalArgumentException(
-          String.format(Locale.ROOT, TOKEN_NAME_EXCEPTION_FORMAT, name));
-    }
+    checkArgument(id != null, String.format(Locale.ROOT, TOKEN_NAME_EXCEPTION_FORMAT, name));
     return id;
   }
 
@@ -164,10 +162,9 @@ public final class TokenUtil {
    * @throws IllegalArgumentException when name is unknown
    */
   public static String getShortDescription(String name) {
-    if (!TOKEN_NAME_TO_VALUE.containsKey(name)) {
-      throw new IllegalArgumentException(
-          String.format(Locale.ROOT, TOKEN_NAME_EXCEPTION_FORMAT, name));
-    }
+    checkArgument(
+        TOKEN_NAME_TO_VALUE.containsKey(name),
+        String.format(Locale.ROOT, TOKEN_NAME_EXCEPTION_FORMAT, name));
 
     final String tokenTypes = "com.puppycrawl.tools.checkstyle.api.tokentypes";
     final ResourceBundle bundle = ResourceBundle.getBundle(tokenTypes, Locale.ROOT);
@@ -332,7 +329,7 @@ public final class TokenUtil {
   public static BitSet asBitSet(String... tokens) {
     return Arrays.stream(tokens)
         .map(String::trim)
-        .filter(Predicate.not(String::isEmpty))
+        .filter(not(String::isEmpty))
         .mapToInt(TokenUtil::getTokenId)
         .collect(BitSet::new, BitSet::set, BitSet::or);
   }
--- a/src/main/java/com/puppycrawl/tools/checkstyle/utils/UnmodifiableCollectionUtil.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/utils/UnmodifiableCollectionUtil.java
@@ -19,13 +19,15 @@
 
 package com.puppycrawl.tools.checkstyle.utils;
 
+import static java.util.stream.Collectors.toUnmodifiableList;
+
+import com.google.common.collect.ImmutableSet;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 /**
  * Note: it simply wraps the existing JDK methods to provide a workaround for Pitest survival on
@@ -68,7 +70,7 @@ public final class UnmodifiableCollectionUtil {
    * @return An unmodifiable List containing elements of the specified type.
    */
   public static <S, T> List<T> unmodifiableList(Collection<S> items, Class<T> elementType) {
-    return items.stream().map(elementType::cast).collect(Collectors.toUnmodifiableList());
+    return items.stream().map(elementType::cast).collect(toUnmodifiableList());
   }
 
   /**
@@ -103,6 +105,6 @@ public final class UnmodifiableCollectionUtil {
    * @return immutable set
    */
   public static <T> Set<T> singleton(T obj) {
-    return Collections.singleton(obj);
+    return ImmutableSet.of(obj);
   }
 }
--- a/src/main/java/com/puppycrawl/tools/checkstyle/utils/XpathUtil.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/utils/XpathUtil.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.utils;
 
+import static java.util.stream.Collectors.joining;
+
 import com.puppycrawl.tools.checkstyle.AstTreeStringPrinter;
 import com.puppycrawl.tools.checkstyle.JavaParser;
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
@@ -34,7 +36,6 @@ import java.util.BitSet;
 import java.util.List;
 import java.util.Locale;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 import net.sf.saxon.Configuration;
 import net.sf.saxon.om.Item;
 import net.sf.saxon.om.NodeInfo;
@@ -194,7 +195,7 @@ public final class XpathUtil {
       return matchingItems.stream()
           .map(item -> ((ElementNode) item).getUnderlyingNode())
           .map(AstTreeStringPrinter::printBranch)
-          .collect(Collectors.joining(DELIMITER));
+          .collect(joining(DELIMITER));
     } catch (XPathException ex) {
       final String errMsg =
           String.format(
--- a/src/main/java/com/puppycrawl/tools/checkstyle/xpath/AbstractNode.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/xpath/AbstractNode.java
@@ -19,7 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.xpath;
 
-import java.util.Collections;
+import static java.util.Collections.unmodifiableList;
+
 import java.util.List;
 import net.sf.saxon.Configuration;
 import net.sf.saxon.event.Receiver;
@@ -91,7 +92,7 @@ public abstract class AbstractNode implements NodeInfo {
     if (children == null) {
       children = createChildren();
     }
-    return Collections.unmodifiableList(children);
+    return unmodifiableList(children);
   }
 
   /**
--- a/src/main/java/com/puppycrawl/tools/checkstyle/xpath/XpathQueryGenerator.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/xpath/XpathQueryGenerator.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.xpath;
 
+import static java.util.stream.Collectors.toUnmodifiableList;
+
 import com.puppycrawl.tools.checkstyle.TreeWalkerAuditEvent;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.api.FileText;
@@ -27,7 +29,6 @@ import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
 import com.puppycrawl.tools.checkstyle.utils.XpathUtil;
 import java.util.ArrayList;
 import java.util.List;
-import java.util.stream.Collectors;
 
 /**
  * Generates xpath queries. Xpath queries are generated based on received {@code DetailAst} element,
@@ -145,7 +146,7 @@ public class XpathQueryGenerator {
   public List<String> generate() {
     return getMatchingAstElements().stream()
         .map(XpathQueryGenerator::generateXpathQuery)
-        .collect(Collectors.toUnmodifiableList());
+        .collect(toUnmodifiableList());
   }
 
   /**
--- a/src/test/java/com/puppycrawl/tools/checkstyle/AbstractAutomaticBeanTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/AbstractAutomaticBeanTest.java
@@ -34,9 +34,9 @@ import org.apache.commons.beanutils.ConvertUtilsBean;
 import org.apache.commons.beanutils.Converter;
 import org.junit.jupiter.api.Test;
 
-public class AbstractAutomaticBeanTest {
+final class AbstractAutomaticBeanTest {
   @Test
-  public void testConfigureNoSuchAttribute() {
+  void configureNoSuchAttribute() {
     final TestBean testBean = new TestBean();
     final DefaultConfiguration conf = new DefaultConfiguration("testConf");
     conf.addProperty("NonExistent", "doesn't matter");
@@ -53,7 +53,7 @@ public class AbstractAutomaticBeanTest {
   }
 
   @Test
-  public void testConfigureNoSuchAttribute2() {
+  void configureNoSuchAttribute2() {
     final TestBean testBean = new TestBean();
     final DefaultConfiguration conf = new DefaultConfiguration("testConf");
     conf.addProperty("privateField", "doesn't matter");
@@ -70,7 +70,7 @@ public class AbstractAutomaticBeanTest {
   }
 
   @Test
-  public void testSetupChildFromBaseClass() throws CheckstyleException {
+  void setupChildFromBaseClass() throws CheckstyleException {
     final TestBean testBean = new TestBean();
     testBean.configure(new DefaultConfiguration("bean config"));
     testBean.setupChild(null);
@@ -90,7 +90,7 @@ public class AbstractAutomaticBeanTest {
   }
 
   @Test
-  public void testSetupInvalidChildFromBaseClass() {
+  void setupInvalidChildFromBaseClass() {
     final TestBean testBean = new TestBean();
     final DefaultConfiguration parentConf = new DefaultConfiguration("parentConf");
     final DefaultConfiguration childConf = new DefaultConfiguration("childConf");
@@ -111,7 +111,7 @@ public class AbstractAutomaticBeanTest {
   }
 
   @Test
-  public void testContextualizeInvocationTargetException() {
+  void contextualizeInvocationTargetException() {
     final TestBean testBean = new TestBean();
     final DefaultContext context = new DefaultContext();
     context.add("exceptionalMethod", 123.0f);
@@ -132,7 +132,7 @@ public class AbstractAutomaticBeanTest {
   }
 
   @Test
-  public void testContextualizeConversionException() {
+  void contextualizeConversionException() {
     final TestBean testBean = new TestBean();
     final DefaultContext context = new DefaultContext();
     context.add("val", "some string");
@@ -153,7 +153,7 @@ public class AbstractAutomaticBeanTest {
   }
 
   @Test
-  public void testTestBean() {
+  void bean() {
     final TestBean testBean = new TestBean();
     testBean.setVal(0);
     testBean.setWrong("wrongVal");
@@ -170,7 +170,7 @@ public class AbstractAutomaticBeanTest {
   }
 
   @Test
-  public void testRegisterIntegralTypes() throws Exception {
+  void registerIntegralTypes() throws Exception {
     final ConvertUtilsBeanStub convertUtilsBean = new ConvertUtilsBeanStub();
     TestUtil.invokeStaticMethod(
         AbstractAutomaticBean.class, "registerIntegralTypes", convertUtilsBean);
@@ -180,7 +180,7 @@ public class AbstractAutomaticBeanTest {
   }
 
   @Test
-  public void testBeanConverters() throws Exception {
+  void beanConverters() throws Exception {
     final ConverterBean bean = new ConverterBean();
 
     // methods are not seen as used by reflection
@@ -214,7 +214,7 @@ public class AbstractAutomaticBeanTest {
   }
 
   @Test
-  public void testBeanConvertersUri2() throws Exception {
+  void beanConvertersUri2() throws Exception {
     final ConverterBean bean = new ConverterBean();
     final DefaultConfiguration config = new DefaultConfiguration("bean");
     config.addProperty("uri", "");
@@ -224,7 +224,7 @@ public class AbstractAutomaticBeanTest {
   }
 
   @Test
-  public void testBeanConvertersUri3() {
+  void beanConvertersUri3() {
     final ConverterBean bean = new ConverterBean();
     final DefaultConfiguration config = new DefaultConfiguration("bean");
     config.addProperty("uri", "BAD");
--- a/src/test/java/com/puppycrawl/tools/checkstyle/AbstractModuleTestSupport.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/AbstractModuleTestSupport.java
@@ -20,7 +20,11 @@
 package com.puppycrawl.tools.checkstyle;
 
 import static com.google.common.truth.Truth.assertWithMessage;
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static java.util.stream.Collectors.toCollection;
+import static java.util.stream.Collectors.toUnmodifiableList;
 
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Maps;
 import com.puppycrawl.tools.checkstyle.LocalizedMessage.Utf8Control;
@@ -48,7 +52,6 @@ import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.ResourceBundle;
-import java.util.stream.Collectors;
 
 public abstract class AbstractModuleTestSupport extends AbstractPathTestSupport {
 
@@ -422,8 +425,7 @@ public abstract class AbstractModuleTestSupport extends AbstractPathTestSupport
    */
   protected final void execute(Configuration config, String... filenames) throws Exception {
     final Checker checker = createChecker(config);
-    final List<File> files =
-        Arrays.stream(filenames).map(File::new).collect(Collectors.toUnmodifiableList());
+    final List<File> files = Arrays.stream(filenames).map(File::new).collect(toUnmodifiableList());
     checker.process(files);
     checker.destroy();
   }
@@ -444,11 +446,11 @@ public abstract class AbstractModuleTestSupport extends AbstractPathTestSupport
         actualViolations.stream()
             .map(violation -> violation.substring(0, violation.indexOf(':')))
             .map(Integer::valueOf)
-            .collect(Collectors.toUnmodifiableList());
+            .collect(toUnmodifiableList());
     final List<Integer> expectedViolationLines =
         testInputViolations.stream()
             .map(TestInputViolation::getLineNo)
-            .collect(Collectors.toUnmodifiableList());
+            .collect(toUnmodifiableList());
     assertWithMessage("Violation lines for %s differ.", file)
         .that(actualViolationLines)
         .isEqualTo(expectedViolationLines);
@@ -471,7 +473,7 @@ public abstract class AbstractModuleTestSupport extends AbstractPathTestSupport
       throws Exception {
     stream.flush();
     stream.reset();
-    final List<File> files = Collections.singletonList(new File(file));
+    final List<File> files = ImmutableList.of(new File(file));
     final Checker checker = createChecker(config);
     final Map<String, List<String>> actualViolations = getActualViolations(checker.process(files));
     checker.destroy();
@@ -490,8 +492,7 @@ public abstract class AbstractModuleTestSupport extends AbstractPathTestSupport
   private Map<String, List<String>> getActualViolations(int errorCount) throws IOException {
     // process each of the lines
     try (ByteArrayInputStream inputStream = new ByteArrayInputStream(stream.toByteArray());
-        LineNumberReader lnr =
-            new LineNumberReader(new InputStreamReader(inputStream, StandardCharsets.UTF_8))) {
+        LineNumberReader lnr = new LineNumberReader(new InputStreamReader(inputStream, UTF_8))) {
       final Map<String, List<String>> actualViolations = new HashMap<>();
       for (String line = lnr.readLine();
           line != null && lnr.getLineNumber() <= errorCount;
@@ -594,7 +595,7 @@ public abstract class AbstractModuleTestSupport extends AbstractPathTestSupport
   protected static String[] removeSuppressed(
       String[] actualViolations, String... suppressedViolations) {
     final List<String> actualViolationsList =
-        Arrays.stream(actualViolations).collect(Collectors.toCollection(ArrayList::new));
+        Arrays.stream(actualViolations).collect(toCollection(ArrayList::new));
     actualViolationsList.removeAll(Arrays.asList(suppressedViolations));
     return actualViolationsList.toArray(CommonUtil.EMPTY_STRING_ARRAY);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/AbstractPathTestSupport.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/AbstractPathTestSupport.java
@@ -19,13 +19,14 @@
 
 package com.puppycrawl.tools.checkstyle;
 
+import static java.util.stream.Collectors.joining;
+
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Paths;
+import java.util.Arrays;
 import java.util.Locale;
-import java.util.stream.Collectors;
-import java.util.stream.Stream;
 import org.junit.jupiter.api.BeforeEach;
 
 public abstract class AbstractPathTestSupport {
@@ -103,7 +104,7 @@ public abstract class AbstractPathTestSupport {
    * @return joined strings
    */
   public static String addEndOfLine(String... strings) {
-    return Stream.of(strings).collect(Collectors.joining(EOL, "", EOL));
+    return Arrays.stream(strings).collect(joining(EOL, "", EOL));
   }
 
   /**
--- a/src/test/java/com/puppycrawl/tools/checkstyle/AbstractXmlTestSupport.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/AbstractXmlTestSupport.java
@@ -21,10 +21,10 @@ package com.puppycrawl.tools.checkstyle;
 
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.common.truth.Truth.assertWithMessage;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.puppycrawl.tools.checkstyle.internal.utils.XmlUtil;
 import java.io.ByteArrayOutputStream;
-import java.nio.charset.StandardCharsets;
 import java.util.Set;
 import java.util.function.BiPredicate;
 import javax.xml.parsers.ParserConfigurationException;
@@ -43,7 +43,7 @@ public abstract class AbstractXmlTestSupport extends AbstractModuleTestSupport {
    */
   protected static Document getOutputStreamXml(ByteArrayOutputStream outputStream)
       throws ParserConfigurationException {
-    final String xml = outputStream.toString(StandardCharsets.UTF_8);
+    final String xml = outputStream.toString(UTF_8);
 
     return XmlUtil.getRawXml("audit output", xml, xml);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/AstTreeStringPrinterTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/AstTreeStringPrinterTest.java
@@ -32,7 +32,7 @@ import java.nio.file.Files;
 import java.nio.file.Paths;
 import org.junit.jupiter.api.Test;
 
-public class AstTreeStringPrinterTest extends AbstractTreeTestSupport {
+final class AstTreeStringPrinterTest extends AbstractTreeTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -40,14 +40,14 @@ public class AstTreeStringPrinterTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testIsProperUtilsClass() throws ReflectiveOperationException {
+  void isProperUtilsClass() throws ReflectiveOperationException {
     assertWithMessage("Constructor is not private")
         .that(isUtilsClassHasPrivateConstructor(AstTreeStringPrinter.class))
         .isTrue();
   }
 
   @Test
-  public void testParseFileThrowable() throws Exception {
+  void parseFileThrowable() throws Exception {
     final File input = new File(getNonCompilablePath("InputAstTreeStringPrinter.java"));
     try {
       AstTreeStringPrinter.printFileAst(input, JavaParser.Options.WITHOUT_COMMENTS);
@@ -63,7 +63,7 @@ public class AstTreeStringPrinterTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testParseFile() throws Exception {
+  void parseFile() throws Exception {
     verifyAst(
         getPath("ExpectedAstTreeStringPrinter.txt"),
         getPath("InputAstTreeStringPrinterComments.java"),
@@ -71,7 +71,7 @@ public class AstTreeStringPrinterTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testPrintBranch() throws Exception {
+  void printBranch() throws Exception {
     final DetailAST ast =
         JavaParser.parseFile(
             new File(getPath("InputAstTreeStringPrinterPrintBranch.java")),
@@ -89,7 +89,7 @@ public class AstTreeStringPrinterTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testPrintAst() throws Exception {
+  void printAst() throws Exception {
     final FileText text =
         new FileText(
             new File(getPath("InputAstTreeStringPrinterComments.java")).getAbsoluteFile(),
@@ -103,7 +103,7 @@ public class AstTreeStringPrinterTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testParseFileWithComments() throws Exception {
+  void parseFileWithComments() throws Exception {
     verifyAst(
         getPath("ExpectedAstTreeStringPrinterComments.txt"),
         getPath("InputAstTreeStringPrinterComments.java"),
@@ -111,35 +111,35 @@ public class AstTreeStringPrinterTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testParseFileWithJavadoc1() throws Exception {
+  void parseFileWithJavadoc1() throws Exception {
     verifyJavaAndJavadocAst(
         getPath("ExpectedAstTreeStringPrinterJavadoc.txt"),
         getPath("InputAstTreeStringPrinterJavadoc.java"));
   }
 
   @Test
-  public void testParseFileWithJavadoc2() throws Exception {
+  void parseFileWithJavadoc2() throws Exception {
     verifyJavaAndJavadocAst(
         getPath("ExpectedAstTreeStringPrinterJavaAndJavadoc.txt"),
         getPath("InputAstTreeStringPrinterJavaAndJavadoc.java"));
   }
 
   @Test
-  public void testParseFileWithJavadoc3() throws Exception {
+  void parseFileWithJavadoc3() throws Exception {
     verifyJavaAndJavadocAst(
         getPath("ExpectedAstTreeStringPrinterAttributesAndMethodsJavadoc.txt"),
         getPath("InputAstTreeStringPrinterAttributesAndMethodsJavadoc.java"));
   }
 
   @Test
-  public void testJavadocPosition() throws Exception {
+  void javadocPosition() throws Exception {
     verifyJavaAndJavadocAst(
         getPath("ExpectedAstTreeStringPrinterJavadocPosition.txt"),
         getPath("InputAstTreeStringPrinterJavadocPosition.java"));
   }
 
   @Test
-  public void testAstTreeBlockComments() throws Exception {
+  void astTreeBlockComments() throws Exception {
     verifyAst(
         getPath("ExpectedAstTreeStringPrinterFullOfBlockComments.txt"),
         getPath("InputAstTreeStringPrinterFullOfBlockComments.java"),
@@ -147,7 +147,7 @@ public class AstTreeStringPrinterTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testAstTreeBlockCommentsCarriageReturn() throws Exception {
+  void astTreeBlockCommentsCarriageReturn() throws Exception {
     verifyAst(
         getPath("ExpectedAstTreeStringPrinterFullOfBlockCommentsCR.txt"),
         getPath("InputAstTreeStringPrinterFullOfBlockCommentsCR.java"),
@@ -155,7 +155,7 @@ public class AstTreeStringPrinterTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testAstTreeSingleLineComments() throws Exception {
+  void astTreeSingleLineComments() throws Exception {
     verifyAst(
         getPath("ExpectedAstTreeStringPrinterFullOfSinglelineComments.txt"),
         getPath("InputAstTreeStringPrinterFullOfSinglelineComments.java"),
@@ -163,7 +163,7 @@ public class AstTreeStringPrinterTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testTextBlocksEscapesAreOneChar() throws Exception {
+  void textBlocksEscapesAreOneChar() throws Exception {
     final String inputFilename = "InputAstTreeStringPrinterTextBlocksEscapesAreOneChar.java";
     final DetailAST ast =
         JavaParser.parseFile(
--- a/src/test/java/com/puppycrawl/tools/checkstyle/AuditEventDefaultFormatterTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/AuditEventDefaultFormatterTest.java
@@ -27,10 +27,10 @@ import com.puppycrawl.tools.checkstyle.api.Violation;
 import com.puppycrawl.tools.checkstyle.internal.utils.TestUtil;
 import org.junit.jupiter.api.Test;
 
-public class AuditEventDefaultFormatterTest {
+final class AuditEventDefaultFormatterTest {
 
   @Test
-  public void testFormatFullyQualifiedModuleNameContainsCheckSuffix() {
+  void formatFullyQualifiedModuleNameContainsCheckSuffix() {
     final Violation violation =
         new Violation(
             1,
@@ -53,7 +53,7 @@ public class AuditEventDefaultFormatterTest {
   }
 
   @Test
-  public void testFormatFullyQualifiedModuleNameDoesNotContainCheckSuffix() {
+  void formatFullyQualifiedModuleNameDoesNotContainCheckSuffix() {
     final Violation violation =
         new Violation(
             1,
@@ -76,7 +76,7 @@ public class AuditEventDefaultFormatterTest {
   }
 
   @Test
-  public void testFormatModuleWithModuleId() {
+  void formatModuleWithModuleId() {
     final Violation violation =
         new Violation(
             1,
@@ -97,7 +97,7 @@ public class AuditEventDefaultFormatterTest {
   }
 
   @Test
-  public void testCalculateBufferLength() throws Exception {
+  void calculateBufferLength() throws Exception {
     final Violation violation =
         new Violation(
             1, 1, "messages.properties", "key", null, SeverityLevel.ERROR, null, getClass(), null);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/CheckerTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/CheckerTest.java
@@ -25,7 +25,11 @@ import static com.puppycrawl.tools.checkstyle.DefaultLogger.AUDIT_FINISHED_MESSA
 import static com.puppycrawl.tools.checkstyle.DefaultLogger.AUDIT_STARTED_MESSAGE;
 import static com.puppycrawl.tools.checkstyle.checks.NewlineAtEndOfFileCheck.MSG_KEY_NO_NEWLINE_EOF;
 import static com.puppycrawl.tools.checkstyle.checks.sizes.LineLengthCheck.MSG_KEY;
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static java.util.Collections.unmodifiableList;
+import static java.util.stream.Collectors.toUnmodifiableList;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.AbstractAutomaticBean.OutputStreamOptions;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck;
@@ -72,7 +76,6 @@ import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
@@ -80,7 +83,6 @@ import java.util.Properties;
 import java.util.Set;
 import java.util.SortedSet;
 import java.util.TreeSet;
-import java.util.stream.Collectors;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
 
@@ -117,7 +119,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDestroy() throws Exception {
+  void destroy() throws Exception {
     final Checker checker = new Checker();
     final DebugAuditAdapter auditAdapter = new DebugAuditAdapter();
     checker.addListener(auditAdapter);
@@ -132,7 +134,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
     checker.destroy();
 
     final File tempFile = File.createTempFile("junit", null, temporaryFolder);
-    checker.process(Collections.singletonList(tempFile));
+    checker.process(ImmutableList.of(tempFile));
     final SortedSet<Violation> violations = new TreeSet<>();
     violations.add(
         new Violation(
@@ -154,7 +156,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAddListener() throws Exception {
+  void addListener() throws Exception {
     final Checker checker = new Checker();
     final DebugAuditAdapter auditAdapter = new DebugAuditAdapter();
     checker.addListener(auditAdapter);
@@ -210,7 +212,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRemoveListener() throws Exception {
+  void removeListener() throws Exception {
     final Checker checker = new Checker();
     final DebugAuditAdapter auditAdapter = new DebugAuditAdapter();
     final DebugAuditAdapter aa2 = new DebugAuditAdapter();
@@ -267,21 +269,21 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAddBeforeExecutionFileFilter() throws Exception {
+  void addBeforeExecutionFileFilter() throws Exception {
     final Checker checker = new Checker();
     final TestBeforeExecutionFileFilter filter = new TestBeforeExecutionFileFilter();
 
     checker.addBeforeExecutionFileFilter(filter);
 
     filter.resetFilter();
-    checker.process(Collections.singletonList(new File("dummy.java")));
+    checker.process(ImmutableList.of(new File("dummy.java")));
     assertWithMessage("Checker.acceptFileStarted() doesn't call filter")
         .that(filter.wasCalled())
         .isTrue();
   }
 
   @Test
-  public void testRemoveBeforeExecutionFileFilter() throws Exception {
+  void removeBeforeExecutionFileFilter() throws Exception {
     final Checker checker = new Checker();
     final TestBeforeExecutionFileFilter filter = new TestBeforeExecutionFileFilter();
     final TestBeforeExecutionFileFilter f2 = new TestBeforeExecutionFileFilter();
@@ -290,7 +292,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
     checker.removeBeforeExecutionFileFilter(filter);
 
     f2.resetFilter();
-    checker.process(Collections.singletonList(new File("dummy.java")));
+    checker.process(ImmutableList.of(new File("dummy.java")));
     assertWithMessage("Checker.acceptFileStarted() doesn't call filter")
         .that(f2.wasCalled())
         .isTrue();
@@ -300,7 +302,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAddFilter() {
+  void addFilter() {
     final Checker checker = new Checker();
     final DebugFilter filter = new DebugFilter();
 
@@ -316,7 +318,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRemoveFilter() {
+  void removeFilter() {
     final Checker checker = new Checker();
     final DebugFilter filter = new DebugFilter();
     final DebugFilter f2 = new DebugFilter();
@@ -337,7 +339,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFileExtensions() throws Exception {
+  void fileExtensions() throws Exception {
     final DefaultConfiguration checkerConfig = new DefaultConfiguration("configuration");
     checkerConfig.addProperty("charset", StandardCharsets.UTF_8.name());
     checkerConfig.addProperty(
@@ -378,7 +380,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoredFileExtensions() throws Exception {
+  void ignoredFileExtensions() throws Exception {
     final DefaultConfiguration checkerConfig = new DefaultConfiguration("configuration");
     checkerConfig.addProperty("charset", StandardCharsets.UTF_8.name());
     final File tempFile = File.createTempFile("junit", null, temporaryFolder);
@@ -413,7 +415,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSetters() {
+  void setters() {
     // all  that is set by reflection, so just make code coverage be happy
     final Checker checker = new Checker();
     checker.setBasedir("some");
@@ -437,7 +439,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoClassLoaderNoModuleFactory() {
+  void noClassLoaderNoModuleFactory() {
     final Checker checker = new Checker();
 
     try {
@@ -451,7 +453,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoModuleFactory() throws Exception {
+  void noModuleFactory() throws Exception {
     final Checker checker = new Checker();
     final ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
 
@@ -465,7 +467,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFinishLocalSetupFullyInitialized() throws Exception {
+  void finishLocalSetupFullyInitialized() throws Exception {
     final Checker checker = new Checker();
     final ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
     checker.setModuleClassLoader(contextClassLoader);
@@ -496,7 +498,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSetupChildExceptions() {
+  void setupChildExceptions() {
     final Checker checker = new Checker();
     final PackageObjectFactory factory =
         new PackageObjectFactory(new HashSet<>(), Thread.currentThread().getContextClassLoader());
@@ -514,7 +516,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSetupChildInvalidProperty() throws Exception {
+  void setupChildInvalidProperty() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(HiddenFieldCheck.class);
     checkConfig.addProperty("$$No such property", null);
     try {
@@ -533,7 +535,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSetupChildListener() throws Exception {
+  void setupChildListener() throws Exception {
     final Checker checker = new Checker();
     final PackageObjectFactory factory =
         new PackageObjectFactory(new HashSet<>(), Thread.currentThread().getContextClassLoader());
@@ -550,7 +552,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDestroyCheckerWithWrongCacheFileNameLength() throws Exception {
+  void destroyCheckerWithWrongCacheFileNameLength() throws Exception {
     final Checker checker = new Checker();
     final PackageObjectFactory factory =
         new PackageObjectFactory(new HashSet<>(), Thread.currentThread().getContextClassLoader());
@@ -572,8 +574,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
 
   /** It is OK to have long test method name here as it describes the test purpose. */
   @Test
-  public void testCacheAndCheckWhichDoesNotImplementExternalResourceHolderInterface()
-      throws Exception {
+  void cacheAndCheckWhichDoesNotImplementExternalResourceHolderInterface() throws Exception {
     assertWithMessage("ExternalResourceHolder has changed his parent")
         .that(ExternalResourceHolder.class.isAssignableFrom(HiddenFieldCheck.class))
         .isFalse();
@@ -610,7 +611,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithCacheWithNoViolation() throws Exception {
+  void withCacheWithNoViolation() throws Exception {
     final Checker checker = new Checker();
     final PackageObjectFactory factory =
         new PackageObjectFactory(new HashSet<>(), Thread.currentThread().getContextClassLoader());
@@ -651,7 +652,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClearExistingCache() throws Exception {
+  void clearExistingCache() throws Exception {
     final DefaultConfiguration checkerConfig = createRootConfig(null);
     checkerConfig.addProperty("charset", StandardCharsets.UTF_8.name());
     final File cacheFile = File.createTempFile("junit", null, temporaryFolder);
@@ -700,7 +701,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClearCache() throws Exception {
+  void clearCache() throws Exception {
     final DefaultConfiguration violationCheck =
         createModuleConfig(DummyFileSetViolationCheck.class);
     final DefaultConfiguration checkerConfig = new DefaultConfiguration("myConfig");
@@ -713,7 +714,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
     checker.configure(checkerConfig);
     checker.addListener(getBriefUtLogger());
 
-    checker.process(Collections.singletonList(new File("dummy.java")));
+    checker.process(ImmutableList.of(new File("dummy.java")));
     checker.clearCache();
     // invoke destroy to persist cache
     final PropertyCacheFile cache = TestUtil.getInternalState(checker, "cacheFile");
@@ -728,7 +729,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void setFileExtension() {
+  void setFileExtension() {
     final Checker checker = new Checker();
     checker.setFileExtensions(".test1", "test2");
     final String[] actual = TestUtil.getInternalState(checker, "fileExtensions");
@@ -738,7 +739,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClearCacheWhenCacheFileIsNotSet() {
+  void clearCacheWhenCacheFileIsNotSet() {
     // The idea of the test is to check that when cache file is not set,
     // the invocation of clearCache method does not throw an exception.
     final Checker checker = new Checker();
@@ -757,7 +758,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
    *     does not require serialization
    */
   @Test
-  public void testCatchErrorInProcessFilesMethod() throws Exception {
+  void catchErrorInProcessFilesMethod() throws Exception {
     // Assume that I/O error is happened when we try to invoke 'lastModified()' method.
     final String errorMessage =
         "Java Virtual Machine is broken"
@@ -813,7 +814,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
    *     does not require serialization
    */
   @Test
-  public void testCatchErrorWithNoFileName() throws Exception {
+  void catchErrorWithNoFileName() throws Exception {
     // Assume that I/O error is happened when we try to invoke 'lastModified()' method.
     final String errorMessage =
         "Java Virtual Machine is broken"
@@ -871,8 +872,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
 
   /** It is OK to have long test method name here as it describes the test purpose. */
   @Test
-  public void testCacheAndFilterWhichDoesNotImplementExternalResourceHolderInterface()
-      throws Exception {
+  void cacheAndFilterWhichDoesNotImplementExternalResourceHolderInterface() throws Exception {
     assertWithMessage("ExternalResourceHolder has changed its parent")
         .that(ExternalResourceHolder.class.isAssignableFrom(DummyFilter.class))
         .isFalse();
@@ -918,8 +918,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   /** It is OK to have long test method name here as it describes the test purpose. */
   // -@cs[ExecutableStatementCount] This test needs to verify many things.
   @Test
-  public void testCacheAndCheckWhichAddsNewResourceLocationButKeepsSameCheckerInstance()
-      throws Exception {
+  void cacheAndCheckWhichAddsNewResourceLocationButKeepsSameCheckerInstance() throws Exception {
     // Use case (https://github.com/checkstyle/checkstyle/pull/3092#issuecomment-218162436):
     // Imagine that cache exists in a file. New version of Checkstyle appear.
     // New release contains update to a some check to have additional external resource.
@@ -1000,7 +999,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClearLazyLoadCacheInDetailAST() throws Exception {
+  void clearLazyLoadCacheInDetailAST() throws Exception {
     final DefaultConfiguration checkConfig1 =
         createModuleConfig(CheckWhichDoesNotRequireCommentNodes.class);
     final DefaultConfiguration checkConfig2 =
@@ -1019,7 +1018,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCacheOnViolationSuppression() throws Exception {
+  void cacheOnViolationSuppression() throws Exception {
     final File cacheFile = File.createTempFile("junit", null, temporaryFolder);
     final DefaultConfiguration violationCheck =
         createModuleConfig(DummyFileSetViolationCheck.class);
@@ -1048,7 +1047,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHaltOnException() throws Exception {
+  void haltOnException() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(CheckWhichThrowsError.class);
     final String filePath = getPath("InputChecker.java");
     try {
@@ -1062,7 +1061,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExceptionWithCache() throws Exception {
+  void exceptionWithCache() throws Exception {
     final File cacheFile = File.createTempFile("junit", null, temporaryFolder);
 
     final DefaultConfiguration checkConfig = createModuleConfig(CheckWhichThrowsError.class);
@@ -1079,7 +1078,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
 
     final String filePath = getPath("InputChecker.java");
     try {
-      checker.process(Collections.singletonList(new File(filePath)));
+      checker.process(ImmutableList.of(new File(filePath)));
       assertWithMessage("Exception is expected").fail();
     } catch (CheckstyleException ex) {
       assertWithMessage("Error message is not expected")
@@ -1107,7 +1106,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
    *     does not require serialization
    */
   @Test
-  public void testCatchErrorWithCache() throws Exception {
+  void catchErrorWithCache() throws Exception {
     final File cacheFile = File.createTempFile("junit", null, temporaryFolder);
 
     final DefaultConfiguration checkerConfig = new DefaultConfiguration("configuration");
@@ -1183,7 +1182,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
    *     does not require serialization
    */
   @Test
-  public void testCatchErrorWithCacheWithNoFileName() throws Exception {
+  void catchErrorWithCacheWithNoFileName() throws Exception {
     final File cacheFile = File.createTempFile("junit", null, temporaryFolder);
 
     final DefaultConfiguration checkerConfig = new DefaultConfiguration("configuration");
@@ -1254,7 +1253,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
    *     does not require serialization
    */
   @Test
-  public void testExceptionWithNoFileName() {
+  void exceptionWithNoFileName() {
     final String errorMessage = "Security Exception";
     final RuntimeException expectedError = new SecurityException(errorMessage);
 
@@ -1302,7 +1301,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
    *     does not require serialization
    */
   @Test
-  public void testExceptionWithCacheAndNoFileName() throws Exception {
+  void exceptionWithCacheAndNoFileName() throws Exception {
     final File cacheFile = File.createTempFile("junit", null, temporaryFolder);
 
     final DefaultConfiguration checkerConfig = new DefaultConfiguration("configuration");
@@ -1361,7 +1360,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHaltOnExceptionOff() throws Exception {
+  void haltOnExceptionOff() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(CheckWhichThrowsError.class);
 
     final DefaultConfiguration treeWalkerConfig = createModuleConfig(TreeWalker.class);
@@ -1381,7 +1380,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTabViolationDefault() throws Exception {
+  void tabViolationDefault() throws Exception {
     final DefaultConfiguration checkConfig =
         createModuleConfig(VerifyPositionAfterTabFileSet.class);
     final String[] expected = {
@@ -1391,7 +1390,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTabViolation() throws Exception {
+  void tabViolation() throws Exception {
     final DefaultConfiguration checkConfig =
         createModuleConfig(VerifyPositionAfterTabFileSet.class);
     final DefaultConfiguration checkerConfig = createRootConfig(checkConfig);
@@ -1403,11 +1402,11 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCheckerProcessCallAllNeededMethodsOfFileSets() throws Exception {
+  void checkerProcessCallAllNeededMethodsOfFileSets() throws Exception {
     final DummyFileSet fileSet = new DummyFileSet();
     final Checker checker = new Checker();
     checker.addFileSetCheck(fileSet);
-    checker.process(Collections.singletonList(new File("dummy.java")));
+    checker.process(ImmutableList.of(new File("dummy.java")));
     final List<String> expected = Arrays.asList("beginProcessing", "finishProcessing", "destroy");
     assertWithMessage("Method calls were not expected")
         .that(fileSet.getMethodCalls())
@@ -1415,7 +1414,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSetFileSetCheckSetsMessageDispatcher() {
+  void setFileSetCheckSetsMessageDispatcher() {
     final DummyFileSet fileSet = new DummyFileSet();
     final Checker checker = new Checker();
     checker.addFileSetCheck(fileSet);
@@ -1425,7 +1424,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAddAuditListenerAsChild() throws Exception {
+  void addAuditListenerAsChild() throws Exception {
     final Checker checker = new Checker();
     final DebugAuditAdapter auditAdapter = new DebugAuditAdapter();
     final PackageObjectFactory factory =
@@ -1442,14 +1441,14 @@ public class CheckerTest extends AbstractModuleTestSupport {
     checker.setModuleFactory(factory);
     checker.setupChild(createModuleConfig(DebugAuditAdapter.class));
     // Let's try fire some events
-    checker.process(Collections.singletonList(new File("dummy.java")));
+    checker.process(ImmutableList.of(new File("dummy.java")));
     assertWithMessage("Checker.fireAuditStarted() doesn't call listener")
         .that(auditAdapter.wasCalled())
         .isTrue();
   }
 
   @Test
-  public void testAddBeforeExecutionFileFilterAsChild() throws Exception {
+  void addBeforeExecutionFileFilterAsChild() throws Exception {
     final Checker checker = new Checker();
     final TestBeforeExecutionFileFilter fileFilter = new TestBeforeExecutionFileFilter();
     final PackageObjectFactory factory =
@@ -1465,14 +1464,14 @@ public class CheckerTest extends AbstractModuleTestSupport {
         };
     checker.setModuleFactory(factory);
     checker.setupChild(createModuleConfig(TestBeforeExecutionFileFilter.class));
-    checker.process(Collections.singletonList(new File("dummy.java")));
+    checker.process(ImmutableList.of(new File("dummy.java")));
     assertWithMessage("Checker.acceptFileStarted() doesn't call listener")
         .that(fileFilter.wasCalled())
         .isTrue();
   }
 
   @Test
-  public void testFileSetCheckInitWhenAddedAsChild() throws Exception {
+  void fileSetCheckInitWhenAddedAsChild() throws Exception {
     final Checker checker = new Checker();
     final DummyFileSet fileSet = new DummyFileSet();
     final PackageObjectFactory factory =
@@ -1494,7 +1493,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
 
   // -@cs[CheckstyleTestMakeup] must use raw class to directly initialize DefaultLogger
   @Test
-  public void testDefaultLoggerClosesItStreams() throws Exception {
+  void defaultLoggerClosesItStreams() throws Exception {
     final Checker checker = new Checker();
     try (CloseAndFlushTestByteArrayOutputStream testInfoOutputStream =
             new CloseAndFlushTestByteArrayOutputStream();
@@ -1530,7 +1529,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
 
   // -@cs[CheckstyleTestMakeup] must use raw class to directly initialize DefaultLogger
   @Test
-  public void testXmlLoggerClosesItStreams() throws Exception {
+  void xmlLoggerClosesItStreams() throws Exception {
     final Checker checker = new Checker();
     try (CloseAndFlushTestByteArrayOutputStream testInfoOutputStream =
         new CloseAndFlushTestByteArrayOutputStream()) {
@@ -1552,7 +1551,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDuplicatedModule() throws Exception {
+  void duplicatedModule() throws Exception {
     // we need to test a module with two instances, one with id and the other not
     final DefaultConfiguration moduleConfig1 = createModuleConfig(NewlineAtEndOfFileCheck.class);
     final DefaultConfiguration moduleConfig2 = createModuleConfig(NewlineAtEndOfFileCheck.class);
@@ -1584,10 +1583,9 @@ public class CheckerTest extends AbstractModuleTestSupport {
 
     // super.verify does not work here, for we change the logger
     out.flush();
-    final int errs = checker.process(Collections.singletonList(new File(path)));
+    final int errs = checker.process(ImmutableList.of(new File(path)));
     try (ByteArrayInputStream inputStream = new ByteArrayInputStream(out.toByteArray());
-        LineNumberReader lnr =
-            new LineNumberReader(new InputStreamReader(inputStream, StandardCharsets.UTF_8))) {
+        LineNumberReader lnr = new LineNumberReader(new InputStreamReader(inputStream, UTF_8))) {
       // we need to ignore the unrelated lines
       final List<String> actual =
           lnr.lines()
@@ -1595,7 +1593,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
               .filter(line -> !getCheckMessage(AUDIT_FINISHED_MESSAGE).equals(line))
               .limit(expected.length)
               .sorted()
-              .collect(Collectors.toUnmodifiableList());
+              .collect(toUnmodifiableList());
       Arrays.sort(expected);
 
       for (int i = 0; i < expected.length; i++) {
@@ -1612,7 +1610,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCachedFile() throws Exception {
+  void cachedFile() throws Exception {
     final Checker checker = createChecker(createModuleConfig(TranslationCheck.class));
     final OutputStream infoStream = new ByteArrayOutputStream();
     final OutputStream errorStream = new ByteArrayOutputStream();
@@ -1625,7 +1623,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
     checker.setCacheFile(cacheFile.getAbsolutePath());
 
     final File testFile = File.createTempFile("testFile", ".java", temporaryFolder);
-    final List<File> files = List.of(testFile, testFile);
+    final List<File> files = ImmutableList.of(testFile, testFile);
     checker.process(files);
 
     assertWithMessage("Cached file should not be processed twice")
@@ -1637,7 +1635,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
 
   @SuppressForbidden
   @Test
-  public void testUnmappableCharacters() throws Exception {
+  void unmappableCharacters() throws Exception {
     final String[] expected = {
       "4: " + getCheckMessage(LineLengthCheck.class, MSG_KEY, 75, 238),
     };
@@ -1652,7 +1650,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testViolationMessageOnIoException() throws Exception {
+  void violationMessageOnIoException() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(CheckWhichThrowsError.class);
 
     final DefaultConfiguration treeWalkerConfig = createModuleConfig(TreeWalker.class);
@@ -1939,7 +1937,7 @@ public class CheckerTest extends AbstractModuleTestSupport {
     }
 
     public List<String> getMethodCalls() {
-      return Collections.unmodifiableList(methodCalls);
+      return unmodifiableList(methodCalls);
     }
 
     public boolean isInitCalled() {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/ConfigurationLoaderTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/ConfigurationLoaderTest.java
@@ -24,6 +24,7 @@ import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.mockito.Mockito.mockConstruction;
 import static org.mockito.Mockito.when;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.ConfigurationLoader.IgnoredModulesOptions;
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
 import com.puppycrawl.tools.checkstyle.api.Configuration;
@@ -34,7 +35,6 @@ import java.lang.reflect.Method;
 import java.nio.file.Files;
 import java.nio.file.Paths;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 import java.util.Properties;
 import org.junit.jupiter.api.Test;
@@ -75,7 +75,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testResourceLoadConfiguration() throws Exception {
+  void resourceLoadConfiguration() throws Exception {
     final Properties props = new Properties();
     props.setProperty("checkstyle.basedir", "basedir");
 
@@ -93,7 +93,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testResourceLoadConfigurationWithMultiThreadConfiguration() throws Exception {
+  void resourceLoadConfigurationWithMultiThreadConfiguration() throws Exception {
     final Properties props = new Properties();
     props.setProperty("checkstyle.basedir", "basedir");
 
@@ -113,7 +113,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testResourceLoadConfigurationWithSingleThreadConfiguration() throws Exception {
+  void resourceLoadConfigurationWithSingleThreadConfiguration() throws Exception {
     final Properties props = new Properties();
     props.setProperty("checkstyle.basedir", "basedir");
 
@@ -134,14 +134,14 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testEmptyConfiguration() throws Exception {
+  void emptyConfiguration() throws Exception {
     final DefaultConfiguration config =
         (DefaultConfiguration) loadConfiguration("InputConfigurationLoaderEmpty.xml");
     verifyConfigNode(config, "Checker", 0, new Properties());
   }
 
   @Test
-  public void testEmptyModuleResolver() throws Exception {
+  void emptyModuleResolver() throws Exception {
     final DefaultConfiguration config =
         (DefaultConfiguration)
             loadConfiguration("InputConfigurationLoaderEmpty.xml", new Properties());
@@ -149,7 +149,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testMissingPropertyName() throws Exception {
+  void missingPropertyName() throws Exception {
     try {
       loadConfiguration("InputConfigurationLoaderMissingPropertyName.xml");
       assertWithMessage("missing property name").fail();
@@ -167,7 +167,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testMissingPropertyNameInMethodWithBooleanParameter() throws Exception {
+  void missingPropertyNameInMethodWithBooleanParameter() throws Exception {
     try {
       final String fName = getPath("InputConfigurationLoaderMissingPropertyName.xml");
       ConfigurationLoader.loadConfiguration(
@@ -188,7 +188,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testMissingPropertyValue() throws Exception {
+  void missingPropertyValue() throws Exception {
     try {
       loadConfiguration("InputConfigurationLoaderMissingPropertyValue.xml");
       assertWithMessage("missing property value").fail();
@@ -206,7 +206,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testMissingConfigName() throws Exception {
+  void missingConfigName() throws Exception {
     try {
       loadConfiguration("InputConfigurationLoaderMissingConfigName.xml");
       assertWithMessage("missing module name").fail();
@@ -224,7 +224,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testMissingConfigParent() throws Exception {
+  void missingConfigParent() throws Exception {
     try {
       loadConfiguration("InputConfigurationLoaderMissingConfigParent.xml");
       assertWithMessage("missing module parent").fail();
@@ -242,7 +242,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testCheckstyleChecks() throws Exception {
+  void checkstyleChecks() throws Exception {
     final Properties props = new Properties();
     props.setProperty("checkstyle.basedir", "basedir");
 
@@ -280,7 +280,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testCustomMessages() throws Exception {
+  void customMessages() throws Exception {
     final Properties props = new Properties();
     props.setProperty("checkstyle.basedir", "basedir");
 
@@ -293,8 +293,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
     final List<String> messages = new ArrayList<>(grandchildren[0].getMessages().values());
     final String expectedKey = "name.invalidPattern";
     final List<String> expectedMessages =
-        Collections.singletonList(
-            "Member ''{0}'' must start with ''m'' (checked pattern ''{1}'').");
+        ImmutableList.of("Member ''{0}'' must start with ''m'' (checked pattern ''{1}'').");
     assertWithMessage("Messages should contain key: " + expectedKey)
         .that(grandchildren[0].getMessages())
         .containsKey(expectedKey);
@@ -321,7 +320,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testReplacePropertiesNoReplace() throws Exception {
+  void replacePropertiesNoReplace() throws Exception {
     final String[] testValues = {
       "", "a", "$a", "{a", "{a}", "a}", "$a}", "$", "a$b",
     };
@@ -336,7 +335,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testReplacePropertiesSyntaxError() throws Exception {
+  void replacePropertiesSyntaxError() throws Exception {
     final Properties props = initProperties();
     try {
       final String value =
@@ -353,7 +352,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testReplacePropertiesMissingProperty() throws Exception {
+  void replacePropertiesMissingProperty() throws Exception {
     final Properties props = initProperties();
     try {
       final String value =
@@ -371,7 +370,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testReplacePropertiesReplace() throws Exception {
+  void replacePropertiesReplace() throws Exception {
     final String[][] testValues = {
       {"${a}", "A"},
       {"x${a}", "xA"},
@@ -404,7 +403,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testSystemEntity() throws Exception {
+  void systemEntity() throws Exception {
     final Properties props = new Properties();
     props.setProperty("checkstyle.basedir", "basedir");
 
@@ -419,7 +418,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testExternalEntity() throws Exception {
+  void externalEntity() throws Exception {
     final Properties props = new Properties();
     props.setProperty("checkstyle.basedir", "basedir");
 
@@ -436,7 +435,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testExternalEntitySubdirectory() throws Exception {
+  void externalEntitySubdirectory() throws Exception {
     final Properties props = new Properties();
     props.setProperty("checkstyle.basedir", "basedir");
 
@@ -453,7 +452,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testExternalEntityFromUri() throws Exception {
+  void externalEntityFromUri() throws Exception {
     final Properties props = new Properties();
     props.setProperty("checkstyle.basedir", "basedir");
 
@@ -472,7 +471,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testIncorrectTag() throws Exception {
+  void incorrectTag() throws Exception {
     final Class<?> aClassParent = ConfigurationLoader.class;
     final Constructor<?> ctorParent =
         aClassParent.getDeclaredConstructor(
@@ -501,7 +500,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testNonExistentPropertyName() throws Exception {
+  void nonExistentPropertyName() throws Exception {
     try {
       loadConfiguration("InputConfigurationLoaderNonexistentProperty.xml");
       assertWithMessage("exception in expected").fail();
@@ -525,7 +524,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testConfigWithIgnore() throws Exception {
+  void configWithIgnore() throws Exception {
     final DefaultConfiguration config =
         (DefaultConfiguration)
             ConfigurationLoader.loadConfiguration(
@@ -539,7 +538,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testConfigWithIgnoreUsingInputSource() throws Exception {
+  void configWithIgnoreUsingInputSource() throws Exception {
     final DefaultConfiguration config =
         (DefaultConfiguration)
             ConfigurationLoader.loadConfiguration(
@@ -556,7 +555,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testConfigCheckerWithIgnore() throws Exception {
+  void configCheckerWithIgnore() throws Exception {
     final DefaultConfiguration config =
         (DefaultConfiguration)
             ConfigurationLoader.loadConfiguration(
@@ -569,7 +568,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testLoadConfigurationWrongUrl() {
+  void loadConfigurationWrongUrl() {
     try {
       ConfigurationLoader.loadConfiguration(
           ";InputConfigurationLoaderModuleIgnoreSeverity.xml",
@@ -585,7 +584,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testLoadConfigurationDeprecated() throws Exception {
+  void loadConfigurationDeprecated() throws Exception {
     final DefaultConfiguration config =
         (DefaultConfiguration)
             ConfigurationLoader.loadConfiguration(
@@ -601,7 +600,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testReplacePropertiesDefault() throws Exception {
+  void replacePropertiesDefault() throws Exception {
     final Properties props = new Properties();
     final String defaultValue = "defaultValue";
 
@@ -614,7 +613,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testLoadConfigurationFromClassPath() throws Exception {
+  void loadConfigurationFromClassPath() throws Exception {
     final DefaultConfiguration config =
         (DefaultConfiguration)
             ConfigurationLoader.loadConfiguration(
@@ -628,7 +627,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testParsePropertyString() throws Exception {
+  void parsePropertyString() throws Exception {
     final List<String> propertyRefs = new ArrayList<>();
     final List<String> fragments = new ArrayList<>();
 
@@ -638,7 +637,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testConstructors() throws Exception {
+  void constructors() throws Exception {
     final Properties props = new Properties();
     props.setProperty("checkstyle.basedir", "basedir");
     final String fName = getPath("InputConfigurationLoaderChecks.xml");
@@ -663,7 +662,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testConfigWithIgnoreExceptionalAttributes() {
+  void configWithIgnoreExceptionalAttributes() {
     try (MockedConstruction<DefaultConfiguration> mocked =
         mockConstruction(
             DefaultConfiguration.class,
@@ -691,7 +690,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testLoadConfiguration3() throws Exception {
+  void loadConfiguration3() throws Exception {
     final String[] configFiles = {
       "InputConfigurationLoaderOldConfig0.xml",
       "InputConfigurationLoaderOldConfig1.xml",
@@ -739,7 +738,7 @@ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testDefaultValuesForNonDefinedProperties() throws Exception {
+  void defaultValuesForNonDefinedProperties() throws Exception {
     final Properties props = new Properties();
     props.setProperty("checkstyle.charset.base", "UTF");
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/DefaultConfigurationTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/DefaultConfigurationTest.java
@@ -26,10 +26,10 @@ import java.util.Map;
 import java.util.TreeMap;
 import org.junit.jupiter.api.Test;
 
-public class DefaultConfigurationTest {
+final class DefaultConfigurationTest {
 
   @Test
-  public void testGetPropertyNames() {
+  void getPropertyNames() {
     final DefaultConfiguration config = new DefaultConfiguration("MyConfig");
     config.addProperty("property", "value");
     final String[] actual = config.getPropertyNames();
@@ -38,7 +38,7 @@ public class DefaultConfigurationTest {
   }
 
   @Test
-  public void testAddPropertyAndGetProperty() throws CheckstyleException {
+  void addPropertyAndGetProperty() throws CheckstyleException {
     final DefaultConfiguration config = new DefaultConfiguration("MyConfig");
     config.addProperty("property", "first");
     assertWithMessage("Invalid property value")
@@ -56,7 +56,7 @@ public class DefaultConfigurationTest {
    */
   @Deprecated(since = "10.2")
   @Test
-  public void testDeprecatedAttributeMethods() throws CheckstyleException {
+  void deprecatedAttributeMethods() throws CheckstyleException {
     final DefaultConfiguration config = new DefaultConfiguration("MyConfig");
     config.addAttribute("attribute", "first");
     final String[] actual = config.getAttributeNames();
@@ -72,13 +72,13 @@ public class DefaultConfigurationTest {
   }
 
   @Test
-  public void testGetName() {
+  void getName() {
     final DefaultConfiguration config = new DefaultConfiguration("MyConfig");
     assertWithMessage("Invalid configuration name").that(config.getName()).isEqualTo("MyConfig");
   }
 
   @Test
-  public void testRemoveChild() {
+  void removeChild() {
     final DefaultConfiguration config = new DefaultConfiguration("MyConfig");
     final DefaultConfiguration configChild = new DefaultConfiguration("childConfig");
     assertWithMessage("Invalid children count").that(config.getChildren().length).isEqualTo(0);
@@ -89,7 +89,7 @@ public class DefaultConfigurationTest {
   }
 
   @Test
-  public void testAddMessageAndGetMessages() {
+  void addMessageAndGetMessages() {
     final DefaultConfiguration config = new DefaultConfiguration("MyConfig");
     config.addMessage("key", "value");
     final Map<String, String> expected = new TreeMap<>();
@@ -98,7 +98,7 @@ public class DefaultConfigurationTest {
   }
 
   @Test
-  public void testExceptionForNonExistentProperty() {
+  void exceptionForNonExistentProperty() {
     final String name = "MyConfig";
     final DefaultConfiguration config = new DefaultConfiguration(name);
     final String propertyName = "NonExistent#$%";
@@ -113,7 +113,7 @@ public class DefaultConfigurationTest {
   }
 
   @Test
-  public void testDefaultMultiThreadConfiguration() {
+  void defaultMultiThreadConfiguration() {
     final String name = "MyConfig";
     final DefaultConfiguration config = new DefaultConfiguration(name);
     final ThreadModeSettings singleThreadMode = ThreadModeSettings.SINGLE_THREAD_MODE_INSTANCE;
@@ -123,7 +123,7 @@ public class DefaultConfigurationTest {
   }
 
   @Test
-  public void testMultiThreadConfiguration() {
+  void multiThreadConfiguration() {
     final String name = "MyConfig";
     final ThreadModeSettings multiThreadMode = new ThreadModeSettings(4, 2);
     final DefaultConfiguration config = new DefaultConfiguration(name, multiThreadMode);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/DefaultLoggerTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/DefaultLoggerTest.java
@@ -20,6 +20,7 @@
 package com.puppycrawl.tools.checkstyle;
 
 import static com.google.common.truth.Truth.assertWithMessage;
+import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assumptions.assumeFalse;
 
@@ -32,7 +33,6 @@ import com.puppycrawl.tools.checkstyle.internal.utils.TestUtil;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
-import java.nio.charset.StandardCharsets;
 import java.text.MessageFormat;
 import java.util.Arrays;
 import java.util.Locale;
@@ -40,17 +40,17 @@ import java.util.ResourceBundle;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Test;
 
-public class DefaultLoggerTest {
+final class DefaultLoggerTest {
 
   private static final Locale DEFAULT_LOCALE = Locale.ENGLISH;
 
   @AfterEach
-  public void tearDown() {
+  void tearDown() {
     ResourceBundle.clearCache();
   }
 
   @Test
-  public void testCtor() {
+  void ctor() {
     final OutputStream infoStream = new ByteArrayOutputStream();
     final ByteArrayOutputStream errorStream = new ByteArrayOutputStream();
     final DefaultLogger dl =
@@ -58,7 +58,7 @@ public class DefaultLoggerTest {
             infoStream, OutputStreamOptions.CLOSE, errorStream, OutputStreamOptions.CLOSE);
     dl.addException(new AuditEvent(5000, "myfile"), new IllegalStateException("upsss"));
     dl.auditFinished(new AuditEvent(6000, "myfile"));
-    final String output = errorStream.toString(StandardCharsets.UTF_8);
+    final String output = errorStream.toString(UTF_8);
     final LocalizedMessage addExceptionMessage = getAddExceptionMessageClass("myfile");
     final String message = addExceptionMessage.getMessage();
     assertWithMessage("Invalid exception").that(output).contains(message);
@@ -69,7 +69,7 @@ public class DefaultLoggerTest {
 
   /** We keep this test for 100% coverage. Until #12873. */
   @Test
-  public void testCtorWithTwoParameters() {
+  void ctorWithTwoParameters() {
     final OutputStream infoStream = new ByteArrayOutputStream();
     final DefaultLogger dl = new DefaultLogger(infoStream, OutputStreamOptions.CLOSE);
     dl.addException(new AuditEvent(5000, "myfile"), new IllegalStateException("upsss"));
@@ -82,7 +82,7 @@ public class DefaultLoggerTest {
 
   /** We keep this test for 100% coverage. Until #12873. */
   @Test
-  public void testCtorWithTwoParametersCloseStreamOptions() {
+  void ctorWithTwoParametersCloseStreamOptions() {
     final OutputStream infoStream = new ByteArrayOutputStream();
     final DefaultLogger dl = new DefaultLogger(infoStream, AutomaticBean.OutputStreamOptions.CLOSE);
     final boolean closeInfo = TestUtil.getInternalState(dl, "closeInfo");
@@ -92,7 +92,7 @@ public class DefaultLoggerTest {
 
   /** We keep this test for 100% coverage. Until #12873. */
   @Test
-  public void testCtorWithTwoParametersNoneStreamOptions() {
+  void ctorWithTwoParametersNoneStreamOptions() {
     final OutputStream infoStream = new ByteArrayOutputStream();
     final DefaultLogger dl = new DefaultLogger(infoStream, AutomaticBean.OutputStreamOptions.NONE);
     final boolean closeInfo = TestUtil.getInternalState(dl, "closeInfo");
@@ -101,7 +101,7 @@ public class DefaultLoggerTest {
   }
 
   @Test
-  public void testCtorWithNullParameter() {
+  void ctorWithNullParameter() {
     final OutputStream infoStream = new ByteArrayOutputStream();
     final DefaultLogger dl = new DefaultLogger(infoStream, OutputStreamOptions.CLOSE);
     dl.addException(new AuditEvent(5000), new IllegalStateException("upsss"));
@@ -113,7 +113,7 @@ public class DefaultLoggerTest {
   }
 
   @Test
-  public void testNewCtorWithTwoParameters() {
+  void newCtorWithTwoParameters() {
     final OutputStream infoStream = new ByteArrayOutputStream();
     final DefaultLogger dl = new DefaultLogger(infoStream, OutputStreamOptions.NONE);
     dl.addException(new AuditEvent(5000, "myfile"), new IllegalStateException("upsss"));
@@ -124,7 +124,7 @@ public class DefaultLoggerTest {
   }
 
   @Test
-  public void testNullInfoStreamOptions() {
+  void nullInfoStreamOptions() {
     final ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
     final IllegalArgumentException ex =
         assertThrows(
@@ -138,7 +138,7 @@ public class DefaultLoggerTest {
   }
 
   @Test
-  public void testNullErrorStreamOptions() {
+  void nullErrorStreamOptions() {
     final ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
     final IllegalArgumentException ex =
         assertThrows(
@@ -158,7 +158,7 @@ public class DefaultLoggerTest {
   }
 
   @Test
-  public void testAddError() {
+  void addError() {
     final OutputStream infoStream = new ByteArrayOutputStream();
     final OutputStream errorStream = new ByteArrayOutputStream();
     final String auditStartMessage = getAuditStartMessage();
@@ -188,7 +188,7 @@ public class DefaultLoggerTest {
   }
 
   @Test
-  public void testAddErrorModuleId() {
+  void addErrorModuleId() {
     final OutputStream infoStream = new ByteArrayOutputStream();
     final OutputStream errorStream = new ByteArrayOutputStream();
     final String auditFinishMessage = getAuditFinishMessage();
@@ -217,7 +217,7 @@ public class DefaultLoggerTest {
   }
 
   @Test
-  public void testAddErrorIgnoreSeverityLevel() {
+  void addErrorIgnoreSeverityLevel() {
     final OutputStream infoStream = new ByteArrayOutputStream();
     final OutputStream errorStream = new ByteArrayOutputStream();
     final DefaultLogger defaultLogger =
@@ -235,7 +235,7 @@ public class DefaultLoggerTest {
   }
 
   @Test
-  public void testFinishLocalSetup() {
+  void finishLocalSetup() {
     final OutputStream infoStream = new ByteArrayOutputStream();
     final DefaultLogger dl = new DefaultLogger(infoStream, OutputStreamOptions.CLOSE);
     dl.finishLocalSetup();
@@ -246,7 +246,7 @@ public class DefaultLoggerTest {
 
   /** Verifies that the language specified with the system property {@code user.language} exists. */
   @Test
-  public void testLanguageIsValid() {
+  void languageIsValid() {
     final String language = DEFAULT_LOCALE.getLanguage();
     assumeFalse(language.isEmpty(), "Locale not set");
     assertWithMessage("Invalid language")
@@ -256,7 +256,7 @@ public class DefaultLoggerTest {
 
   /** Verifies that the country specified with the system property {@code user.country} exists. */
   @Test
-  public void testCountryIsValid() {
+  void countryIsValid() {
     final String country = DEFAULT_LOCALE.getCountry();
     assumeFalse(country.isEmpty(), "Locale not set");
     assertWithMessage("Invalid country")
@@ -265,7 +265,7 @@ public class DefaultLoggerTest {
   }
 
   @Test
-  public void testNewCtor() throws Exception {
+  void newCtor() throws Exception {
     final ResourceBundle bundle =
         ResourceBundle.getBundle(Definitions.CHECKSTYLE_BUNDLE, Locale.ENGLISH);
     final String auditStartedMessage = bundle.getString(DefaultLogger.AUDIT_STARTED_MESSAGE);
@@ -284,8 +284,8 @@ public class DefaultLoggerTest {
         dl.auditStarted(null);
         dl.addException(new AuditEvent(5000, "myfile"), new IllegalStateException("upsss"));
         dl.auditFinished(new AuditEvent(6000, "myfile"));
-        infoOutput = infoStream.toString(StandardCharsets.UTF_8);
-        errorOutput = errorStream.toString(StandardCharsets.UTF_8);
+        infoOutput = infoStream.toString(UTF_8);
+        errorOutput = errorStream.toString(UTF_8);
 
         assertWithMessage("Info stream should be closed")
             .that(infoStream.closedCount)
@@ -310,7 +310,7 @@ public class DefaultLoggerTest {
   }
 
   @Test
-  public void testStreamsNotClosedByLogger() throws IOException {
+  void streamsNotClosedByLogger() throws IOException {
     try (MockByteArrayOutputStream infoStream = new MockByteArrayOutputStream();
         MockByteArrayOutputStream errorStream = new MockByteArrayOutputStream()) {
       final DefaultLogger defaultLogger =
--- a/src/test/java/com/puppycrawl/tools/checkstyle/DefinitionsTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/DefinitionsTest.java
@@ -24,10 +24,10 @@ import static com.puppycrawl.tools.checkstyle.internal.utils.TestUtil.isUtilsCla
 
 import org.junit.jupiter.api.Test;
 
-public class DefinitionsTest {
+final class DefinitionsTest {
 
   @Test
-  public void testIsProperUtilsClass() throws ReflectiveOperationException {
+  void isProperUtilsClass() throws ReflectiveOperationException {
     assertWithMessage("Constructor is not private")
         .that(isUtilsClassHasPrivateConstructor(Definitions.class))
         .isTrue();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/DetailAstImplTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/DetailAstImplTest.java
@@ -20,6 +20,7 @@
 package com.puppycrawl.tools.checkstyle;
 
 import static com.google.common.truth.Truth.assertWithMessage;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
@@ -28,7 +29,6 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.io.File;
 import java.io.Writer;
 import java.lang.reflect.Method;
-import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.text.MessageFormat;
 import java.util.ArrayList;
@@ -43,7 +43,7 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
 
 /** TestCase to check DetailAST. */
-public class DetailAstImplTest extends AbstractModuleTestSupport {
+final class DetailAstImplTest extends AbstractModuleTestSupport {
 
   // Ignores file which are not meant to have root node intentionally.
   public static final Set<String> NO_ROOT_FILES =
@@ -74,7 +74,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInitialize() {
+  void initialize() {
     final DetailAstImpl ast = new DetailAstImpl();
     ast.setText("test");
     ast.setType(1);
@@ -94,7 +94,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInitializeToken() {
+  void initializeToken() {
     final CommonToken token = new CommonToken(1);
     token.setText("test");
     token.setLine(2);
@@ -110,7 +110,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetChildCount() throws Exception {
+  void getChildCount() throws Exception {
     final DetailAstImpl root = new DetailAstImpl();
     final DetailAstImpl firstLevelA = new DetailAstImpl();
     final DetailAstImpl firstLevelB = new DetailAstImpl();
@@ -146,7 +146,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHasChildren() {
+  void hasChildren() {
     final DetailAstImpl root = new DetailAstImpl();
     final DetailAstImpl child = new DetailAstImpl();
     root.setFirstChild(child);
@@ -156,7 +156,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetChildCountType() throws Exception {
+  void getChildCountType() throws Exception {
     final DetailAstImpl root = new DetailAstImpl();
     final DetailAstImpl firstLevelA = new DetailAstImpl();
     final DetailAstImpl firstLevelB = new DetailAstImpl();
@@ -185,7 +185,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSetSiblingNull() throws Exception {
+  void setSiblingNull() throws Exception {
     final DetailAstImpl root = new DetailAstImpl();
     final DetailAstImpl firstLevelA = new DetailAstImpl();
 
@@ -201,7 +201,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAddPreviousSibling() {
+  void addPreviousSibling() {
     final DetailAST previousSibling = new DetailAstImpl();
     final DetailAstImpl instance = new DetailAstImpl();
     final DetailAstImpl parent = new DetailAstImpl();
@@ -250,7 +250,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAddPreviousSiblingNullParent() {
+  void addPreviousSiblingNullParent() {
     final DetailAstImpl child = new DetailAstImpl();
     final DetailAST newSibling = new DetailAstImpl();
 
@@ -261,7 +261,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInsertSiblingBetween() throws Exception {
+  void insertSiblingBetween() throws Exception {
     final DetailAstImpl root = new DetailAstImpl();
     final DetailAstImpl firstLevelA = new DetailAstImpl();
     final DetailAST firstLevelB = new DetailAstImpl();
@@ -291,7 +291,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBranchContains() {
+  void branchContains() {
     final DetailAstImpl root = createToken(null, TokenTypes.CLASS_DEF);
     final DetailAstImpl modifiers = createToken(root, TokenTypes.MODIFIERS);
     createToken(modifiers, TokenTypes.LITERAL_PUBLIC);
@@ -312,7 +312,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClearBranchTokenTypes() throws Exception {
+  void clearBranchTokenTypes() throws Exception {
     final DetailAstImpl parent = new DetailAstImpl();
     final DetailAstImpl child = new DetailAstImpl();
     parent.setFirstChild(child);
@@ -348,7 +348,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCacheBranchTokenTypes() {
+  void cacheBranchTokenTypes() {
     final DetailAST root = new DetailAstImpl();
     final BitSet bitSet = new BitSet();
     bitSet.set(999);
@@ -358,7 +358,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClearChildCountCache() {
+  void clearChildCountCache() {
     final DetailAstImpl parent = new DetailAstImpl();
     final DetailAstImpl child = new DetailAstImpl();
     parent.setFirstChild(child);
@@ -384,7 +384,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCacheGetChildCount() {
+  void cacheGetChildCount() {
     final DetailAST root = new DetailAstImpl();
 
     TestUtil.setInternalState(root, "childCount", 999);
@@ -392,7 +392,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAddNextSibling() {
+  void addNextSibling() {
     final DetailAstImpl parent = new DetailAstImpl();
     final DetailAstImpl child = new DetailAstImpl();
     final DetailAstImpl sibling = new DetailAstImpl();
@@ -425,7 +425,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAddNextSibling2() {
+  void addNextSibling2() {
     final DetailAstImpl parent = new DetailAstImpl();
     final DetailAstImpl child = new DetailAstImpl();
     parent.setFirstChild(child);
@@ -443,7 +443,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAddNextSibling3() {
+  void addNextSibling3() {
     final DetailAstImpl parent = new DetailAstImpl();
     final DetailAstImpl child = new DetailAstImpl();
     final DetailAstImpl sibling = new DetailAstImpl();
@@ -456,7 +456,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAddNextSibling4() {
+  void addNextSibling4() {
     final DetailAstImpl parent = new DetailAstImpl();
     parent.setText("Parent");
     final DetailAstImpl child = new DetailAstImpl();
@@ -470,7 +470,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAddNextSiblingNullParent() {
+  void addNextSiblingNullParent() {
     final DetailAstImpl child = new DetailAstImpl();
     final DetailAstImpl newSibling = new DetailAstImpl();
     final DetailAstImpl oldParent = new DetailAstImpl();
@@ -483,7 +483,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetLineNo() {
+  void getLineNo() {
     final DetailAstImpl root1 = new DetailAstImpl();
     root1.setLineNo(1);
     assertWithMessage("Invalid line number").that(root1.getLineNo()).isEqualTo(1);
@@ -509,7 +509,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetColumnNo() {
+  void getColumnNo() {
     final DetailAstImpl root1 = new DetailAstImpl();
     root1.setColumnNo(1);
     assertWithMessage("Invalid column number").that(root1.getColumnNo()).isEqualTo(1);
@@ -537,7 +537,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFindFirstToken() {
+  void findFirstToken() {
     final DetailAstImpl root = new DetailAstImpl();
     final DetailAstImpl firstChild = new DetailAstImpl();
     firstChild.setType(TokenTypes.IDENT);
@@ -559,10 +559,10 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testManyComments() throws Exception {
+  void manyComments() throws Exception {
     final File file = new File(temporaryFolder, "InputDetailASTManyComments.java");
 
-    try (Writer bw = Files.newBufferedWriter(file.toPath(), StandardCharsets.UTF_8)) {
+    try (Writer bw = Files.newBufferedWriter(file.toPath(), UTF_8)) {
       bw.write("/*\ncom.puppycrawl.tools.checkstyle.checks.TodoCommentCheck\n\n\n\n*/\n");
       bw.write("class C {\n");
       for (int i = 0; i <= 30000; i++) {
@@ -576,7 +576,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTreeStructure() throws Exception {
+  void treeStructure() throws Exception {
     final List<File> files =
         getAllFiles(new File("src/test/resources/com/puppycrawl/tools/checkstyle"));
 
@@ -592,7 +592,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testToString() {
+  void testToString() {
     final DetailAstImpl ast = new DetailAstImpl();
     ast.setText("text");
     ast.setColumnNo(1);
@@ -601,7 +601,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRemoveChildren() {
+  void removeChildren() {
     final DetailAstImpl parent = new DetailAstImpl();
     final DetailAstImpl child1 = new DetailAstImpl();
     parent.setFirstChild(child1);
@@ -614,7 +614,7 @@ public class DetailAstImplTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAddChild() {
+  void addChild() {
     final DetailAstImpl grandParent = new DetailAstImpl();
     grandParent.setText("grandparent");
     final DetailAstImpl parent = new DetailAstImpl();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/DetailNodeTreeStringPrinterTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/DetailNodeTreeStringPrinterTest.java
@@ -30,7 +30,7 @@ import com.puppycrawl.tools.checkstyle.internal.utils.TestUtil;
 import java.io.File;
 import org.junit.jupiter.api.Test;
 
-public class DetailNodeTreeStringPrinterTest extends AbstractTreeTestSupport {
+final class DetailNodeTreeStringPrinterTest extends AbstractTreeTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -38,21 +38,21 @@ public class DetailNodeTreeStringPrinterTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testIsProperUtilsClass() throws ReflectiveOperationException {
+  void isProperUtilsClass() throws ReflectiveOperationException {
     assertWithMessage("Constructor is not private")
         .that(isUtilsClassHasPrivateConstructor(DetailNodeTreeStringPrinter.class))
         .isTrue();
   }
 
   @Test
-  public void testParseFile() throws Exception {
+  void parseFile() throws Exception {
     verifyJavadocTree(
         getPath("ExpectedDetailNodeTreeStringPrinterJavadocComment.txt"),
         getPath("InputDetailNodeTreeStringPrinterJavadocComment.javadoc"));
   }
 
   @Test
-  public void testParseFileWithError() throws Exception {
+  void parseFileWithError() throws Exception {
     final File file = new File(getPath("InputDetailNodeTreeStringPrinterJavadocWithError.javadoc"));
     try {
       DetailNodeTreeStringPrinter.printFileAst(file);
@@ -70,14 +70,14 @@ public class DetailNodeTreeStringPrinterTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testNoUnnecessaryTextInJavadocAst() throws Exception {
+  void noUnnecessaryTextInJavadocAst() throws Exception {
     verifyJavadocTree(
         getPath("ExpectedDetailNodeTreeStringPrinterNoUnnecessaryTextInJavadocAst.txt"),
         getPath("InputDetailNodeTreeStringPrinterNoUnnecessaryTextInJavadocAst.javadoc"));
   }
 
   @Test
-  public void testMissedHtmlTagParseErrorMessage() throws Exception {
+  void missedHtmlTagParseErrorMessage() throws Exception {
     final String actual =
         TestUtil.invokeStaticMethod(
             DetailNodeTreeStringPrinter.class,
@@ -98,7 +98,7 @@ public class DetailNodeTreeStringPrinterTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testParseErrorMessage() throws Exception {
+  void parseErrorMessage() throws Exception {
     final String actual =
         TestUtil.invokeStaticMethod(
             DetailNodeTreeStringPrinter.class,
@@ -124,7 +124,7 @@ public class DetailNodeTreeStringPrinterTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testWrongSingletonParseErrorMessage() throws Exception {
+  void wrongSingletonParseErrorMessage() throws Exception {
     final String actual =
         TestUtil.invokeStaticMethod(
             DetailNodeTreeStringPrinter.class,
@@ -146,7 +146,7 @@ public class DetailNodeTreeStringPrinterTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testUnescapedJavaCodeWithGenericsInJavadoc() throws Exception {
+  void unescapedJavaCodeWithGenericsInJavadoc() throws Exception {
     final File file =
         new File(
             getPath(
@@ -168,7 +168,7 @@ public class DetailNodeTreeStringPrinterTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testNoViableAltException() throws Exception {
+  void noViableAltException() throws Exception {
     final File file =
         new File(getPath("InputDetailNodeTreeStringPrinterNoViableAltException.javadoc"));
     try {
@@ -192,7 +192,7 @@ public class DetailNodeTreeStringPrinterTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testHtmlTagCloseBeforeTagOpen() throws Exception {
+  void htmlTagCloseBeforeTagOpen() throws Exception {
     final File file =
         new File(getPath("InputDetailNodeTreeStringPrinterHtmlTagCloseBeforeTagOpen.javadoc"));
     try {
@@ -216,7 +216,7 @@ public class DetailNodeTreeStringPrinterTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testWrongHtmlTagOrder() throws Exception {
+  void wrongHtmlTagOrder() throws Exception {
     final File file =
         new File(getPath("InputDetailNodeTreeStringPrinterWrongHtmlTagOrder.javadoc"));
     try {
@@ -235,7 +235,7 @@ public class DetailNodeTreeStringPrinterTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testOmittedStartTagForHtmlElement() throws Exception {
+  void omittedStartTagForHtmlElement() throws Exception {
     final File file =
         new File(getPath("InputDetailNodeTreeStringPrinterOmittedStartTagForHtmlElement.javadoc"));
     try {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/JavaAstVisitorTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/JavaAstVisitorTest.java
@@ -20,6 +20,7 @@
 package com.puppycrawl.tools.checkstyle;
 
 import static com.google.common.truth.Truth.assertWithMessage;
+import static java.util.stream.Collectors.toUnmodifiableSet;
 
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.api.FileContents;
@@ -37,13 +38,12 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Set;
-import java.util.stream.Collectors;
 import org.antlr.v4.runtime.CharStream;
 import org.antlr.v4.runtime.CharStreams;
 import org.antlr.v4.runtime.CommonTokenStream;
 import org.junit.jupiter.api.Test;
 
-public class JavaAstVisitorTest extends AbstractModuleTestSupport {
+final class JavaAstVisitorTest extends AbstractModuleTestSupport {
 
   /**
    * If a visit method is not overridden, we should explain why we do not 'visit' the parse tree at
@@ -97,7 +97,7 @@ public class JavaAstVisitorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllVisitMethodsAreOverridden() {
+  void allVisitMethodsAreOverridden() {
     final Method[] baseVisitMethods = JavaLanguageParserBaseVisitor.class.getDeclaredMethods();
     final Method[] visitMethods = JavaAstVisitor.class.getDeclaredMethods();
 
@@ -107,7 +107,7 @@ public class JavaAstVisitorTest extends AbstractModuleTestSupport {
             .filter(method -> method.getName().contains("visit"))
             .filter(method -> method.getModifiers() == Modifier.PUBLIC)
             .map(Method::getName)
-            .collect(Collectors.toUnmodifiableSet());
+            .collect(toUnmodifiableSet());
 
     final Set<String> filteredVisitMethodNames =
         Arrays.stream(visitMethods)
@@ -117,7 +117,7 @@ public class JavaAstVisitorTest extends AbstractModuleTestSupport {
             .filter(method -> !"visit".equals(method.getName()))
             .filter(method -> method.getModifiers() == Modifier.PUBLIC)
             .map(Method::getName)
-            .collect(Collectors.toUnmodifiableSet());
+            .collect(toUnmodifiableSet());
 
     final String message =
         "Visit methods in 'JavaLanguageParserBaseVisitor' generated from "
@@ -131,7 +131,7 @@ public class JavaAstVisitorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOrderOfVisitMethodsAndProductionRules() throws Exception {
+  void orderOfVisitMethodsAndProductionRules() throws Exception {
     // Order of BaseVisitor's generated 'visit' methods match the order of
     // production rules in 'JavaLanguageParser.g4'.
     final String baseVisitorFilename =
@@ -200,7 +200,7 @@ public class JavaAstVisitorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNullSelfInAddLastSibling() throws Exception {
+  void nullSelfInAddLastSibling() throws Exception {
     final Method addLastSibling =
         JavaAstVisitor.class.getDeclaredMethod(
             "addLastSibling", DetailAstImpl.class, DetailAstImpl.class);
@@ -227,7 +227,7 @@ public class JavaAstVisitorTest extends AbstractModuleTestSupport {
    * @throws Exception if input file does not exist
    */
   @Test
-  public void testNoStackOverflowOnDeepStringConcat() throws Exception {
+  void noStackOverflowOnDeepStringConcat() throws Exception {
     final File file =
         new File(getPath("InputJavaAstVisitorNoStackOverflowOnDeepStringConcat.java"));
     final FileText fileText = new FileText(file, StandardCharsets.UTF_8.name());
--- a/src/test/java/com/puppycrawl/tools/checkstyle/JavaParserTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/JavaParserTest.java
@@ -34,7 +34,7 @@ import java.util.List;
 import java.util.Optional;
 import org.junit.jupiter.api.Test;
 
-public class JavaParserTest extends AbstractModuleTestSupport {
+final class JavaParserTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -42,21 +42,21 @@ public class JavaParserTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIsProperUtilsClass() throws ReflectiveOperationException {
+  void isProperUtilsClass() throws ReflectiveOperationException {
     assertWithMessage("Constructor is not private")
         .that(TestUtil.isUtilsClassHasPrivateConstructor(JavaParser.class))
         .isTrue();
   }
 
   @Test
-  public void testNullRootWithComments() {
+  void nullRootWithComments() {
     assertWithMessage("Invalid return root")
         .that(JavaParser.appendHiddenCommentNodes(null))
         .isNull();
   }
 
   @Test
-  public void testAppendHiddenBlockCommentNodes() throws Exception {
+  void appendHiddenBlockCommentNodes() throws Exception {
     final DetailAST root =
         JavaParser.parseFile(
             new File(getPath("InputJavaParserHiddenComments.java")),
@@ -68,7 +68,7 @@ public class JavaParserTest extends AbstractModuleTestSupport {
 
     assertWithMessage("Block comment should be present").that(blockComment.isPresent()).isTrue();
 
-    final DetailAST comment = blockComment.get();
+    final DetailAST comment = blockComment.orElseThrow();
 
     assertWithMessage("Unexpected line number").that(comment.getLineNo()).isEqualTo(3);
     assertWithMessage("Unexpected column number").that(comment.getColumnNo()).isEqualTo(0);
@@ -84,7 +84,7 @@ public class JavaParserTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAppendHiddenSingleLineCommentNodes() throws Exception {
+  void appendHiddenSingleLineCommentNodes() throws Exception {
     final DetailAST root =
         JavaParser.parseFile(
             new File(getPath("InputJavaParserHiddenComments.java")),
@@ -97,7 +97,7 @@ public class JavaParserTest extends AbstractModuleTestSupport {
         .that(singleLineComment.isPresent())
         .isTrue();
 
-    final DetailAST comment = singleLineComment.get();
+    final DetailAST comment = singleLineComment.orElseThrow();
 
     assertWithMessage("Unexpected line number").that(comment.getLineNo()).isEqualTo(13);
     assertWithMessage("Unexpected column number").that(comment.getColumnNo()).isEqualTo(0);
@@ -116,7 +116,7 @@ public class JavaParserTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAppendHiddenSingleLineCommentNodes2() throws Exception {
+  void appendHiddenSingleLineCommentNodes2() throws Exception {
     final DetailAST root =
         JavaParser.parseFile(
             new File(getPath("InputJavaParserHiddenComments2.java")),
@@ -129,7 +129,7 @@ public class JavaParserTest extends AbstractModuleTestSupport {
         .that(singleLineComment.isPresent())
         .isTrue();
 
-    final DetailAST comment = singleLineComment.get();
+    final DetailAST comment = singleLineComment.orElseThrow();
 
     assertWithMessage("Unexpected line number").that(comment.getLineNo()).isEqualTo(1);
     assertWithMessage("Unexpected column number").that(comment.getColumnNo()).isEqualTo(4);
@@ -148,7 +148,7 @@ public class JavaParserTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDontAppendCommentNodes() throws Exception {
+  void dontAppendCommentNodes() throws Exception {
     final DetailAST root =
         JavaParser.parseFile(
             new File(getPath("InputJavaParserHiddenComments.java")),
@@ -163,7 +163,7 @@ public class JavaParserTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testParseException() throws Exception {
+  void parseException() throws Exception {
     final File input = new File(getNonCompilablePath("InputJavaParser.java"));
     try {
       JavaParser.parseFile(input, JavaParser.Options.WITH_COMMENTS);
@@ -188,7 +188,7 @@ public class JavaParserTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testComments() throws Exception {
+  void comments() throws Exception {
     final DetailAST root =
         JavaParser.parseFile(
             new File(getPath("InputJavaParserHiddenComments3.java")),
@@ -204,7 +204,7 @@ public class JavaParserTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJava14TextBlocks() throws Exception {
+  void java14TextBlocks() throws Exception {
     final DetailAST root =
         JavaParser.parseFile(
             new File(getNonCompilablePath("InputJavaParserTextBlocks.java")),
@@ -218,7 +218,7 @@ public class JavaParserTest extends AbstractModuleTestSupport {
         .that(textBlockContent.isPresent())
         .isTrue();
 
-    final DetailAST content = textBlockContent.get();
+    final DetailAST content = textBlockContent.orElseThrow();
     final String expectedContents = "\n                 string";
 
     assertWithMessage("Unexpected line number").that(content.getLineNo()).isEqualTo(5);
@@ -229,7 +229,7 @@ public class JavaParserTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoFreezeOnDeeplyNestedLambdas() throws Exception {
+  void noFreezeOnDeeplyNestedLambdas() throws Exception {
     final File file =
         new File(getNonCompilablePath("InputJavaParserNoFreezeOnDeeplyNestedLambdas.java"));
     assertWithMessage("File parsing should complete successfully.")
@@ -238,7 +238,7 @@ public class JavaParserTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFullJavaIdentifierSupport() throws Exception {
+  void fullJavaIdentifierSupport() throws Exception {
     final File file =
         new File(getNonCompilablePath("InputJavaParserFullJavaIdentifierSupport.java"));
     assertWithMessage("File parsing should complete successfully.")
@@ -247,7 +247,7 @@ public class JavaParserTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testReturnValueOfAppendHiddenCommentNodes() throws Exception {
+  void returnValueOfAppendHiddenCommentNodes() throws Exception {
     final String[] expected = {
       "9:1: " + getCheckMessage(JavadocContentLocationCheck.class, MSG_JAVADOC_CONTENT_SECOND_LINE),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/JavadocDetailNodeParserTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/JavadocDetailNodeParserTest.java
@@ -27,7 +27,7 @@ import java.nio.file.Files;
 import java.nio.file.Paths;
 import org.junit.jupiter.api.Test;
 
-public class JavadocDetailNodeParserTest extends AbstractModuleTestSupport {
+final class JavadocDetailNodeParserTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class JavadocDetailNodeParserTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testParseJavadocAsDetailNode() throws Exception {
+  void parseJavadocAsDetailNode() throws Exception {
     final DetailAST ast =
         JavaParser.parseFile(
                 new File(getPath("InputJavadocDetailNodeParser.java")),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/JavadocPropertiesGeneratorTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/JavadocPropertiesGeneratorTest.java
@@ -20,13 +20,13 @@
 package com.puppycrawl.tools.checkstyle;
 
 import static com.google.common.truth.Truth.assertWithMessage;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
 import com.puppycrawl.tools.checkstyle.internal.utils.TestUtil;
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.IOException;
-import java.nio.charset.StandardCharsets;
 import java.util.Locale;
 import org.apache.commons.io.FileUtils;
 import org.itsallcode.io.Capturable;
@@ -39,7 +39,7 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 
 @ExtendWith({SystemErrGuard.class, SystemOutGuard.class})
-public class JavadocPropertiesGeneratorTest extends AbstractPathTestSupport {
+final class JavadocPropertiesGeneratorTest extends AbstractPathTestSupport {
 
   private static final String EOL = System.lineSeparator();
   private static final String USAGE =
@@ -87,7 +87,7 @@ public class JavadocPropertiesGeneratorTest extends AbstractPathTestSupport {
    * @param systemOut wrapper for {@code System.out}
    */
   @BeforeEach
-  public void setUp(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void setUp(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     systemErr.captureMuted();
     systemOut.captureMuted();
 
@@ -95,14 +95,14 @@ public class JavadocPropertiesGeneratorTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testIsProperUtilsClass() throws ReflectiveOperationException {
+  void isProperUtilsClass() throws ReflectiveOperationException {
     assertWithMessage("Constructor is not private")
         .that(TestUtil.isUtilsClassHasPrivateConstructor(JavadocPropertiesGenerator.class))
         .isTrue();
   }
 
   @Test
-  public void testNonExistentArgument(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
+  void nonExistentArgument(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
       throws Exception {
     JavadocPropertiesGenerator.main("--nonexistent-argument");
 
@@ -117,7 +117,7 @@ public class JavadocPropertiesGeneratorTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testNoDestfileSpecified(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
+  void noDestfileSpecified(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
       throws Exception {
     JavadocPropertiesGenerator.main(getPath("InputMain.java"));
 
@@ -128,7 +128,7 @@ public class JavadocPropertiesGeneratorTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testNoInputSpecified(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
+  void noInputSpecified(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
       throws Exception {
     JavadocPropertiesGenerator.main("--destfile", DESTFILE_ABSOLUTE_PATH);
 
@@ -139,8 +139,7 @@ public class JavadocPropertiesGeneratorTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testNotClass(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
-      throws Exception {
+  void notClass(@SysErr Capturable systemErr, @SysOut Capturable systemOut) throws Exception {
     JavadocPropertiesGenerator.main(
         "--destfile",
         DESTFILE_ABSOLUTE_PATH,
@@ -150,8 +149,7 @@ public class JavadocPropertiesGeneratorTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testNotExistentInputSpecified(
-      @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void notExistentInputSpecified(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     try {
       JavadocPropertiesGenerator.main("--destfile", DESTFILE_ABSOLUTE_PATH, "NotExistent.java");
       assertWithMessage("Exception was expected").fail();
@@ -177,8 +175,8 @@ public class JavadocPropertiesGeneratorTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testInvalidDestinationSpecified(
-      @SysErr Capturable systemErr, @SysOut Capturable systemOut) throws Exception {
+  void invalidDestinationSpecified(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
+      throws Exception {
     try {
       // Passing a folder name will cause the FileNotFoundException.
       JavadocPropertiesGenerator.main(
@@ -202,8 +200,7 @@ public class JavadocPropertiesGeneratorTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testCorrect(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
-      throws Exception {
+  void correct(@SysErr Capturable systemErr, @SysOut Capturable systemOut) throws Exception {
     final String expectedContent =
         "EOF1=The end of file token."
             + EOL
@@ -224,13 +221,12 @@ public class JavadocPropertiesGeneratorTest extends AbstractPathTestSupport {
         DESTFILE_ABSOLUTE_PATH);
     assertWithMessage("Unexpected error log").that(systemErr.getCapturedData()).isEqualTo("");
     assertWithMessage("Unexpected output log").that(systemOut.getCapturedData()).isEqualTo("");
-    final String fileContent = FileUtils.readFileToString(DESTFILE, StandardCharsets.UTF_8);
+    final String fileContent = FileUtils.readFileToString(DESTFILE, UTF_8);
     assertWithMessage("File content is not expected").that(fileContent).isEqualTo(expectedContent);
   }
 
   @Test
-  public void testEmptyJavadoc(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
-      throws Exception {
+  void emptyJavadoc(@SysErr Capturable systemErr, @SysOut Capturable systemOut) throws Exception {
     JavadocPropertiesGenerator.main(
         getPath("InputJavadocPropertiesGeneratorEmptyJavadoc.java"),
         "--destfile",
@@ -242,8 +238,7 @@ public class JavadocPropertiesGeneratorTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testNotConstants(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
-      throws Exception {
+  void notConstants(@SysErr Capturable systemErr, @SysOut Capturable systemOut) throws Exception {
     JavadocPropertiesGenerator.main(
         getPath("InputJavadocPropertiesGeneratorNotConstants.java"),
         "--destfile",
@@ -255,15 +250,14 @@ public class JavadocPropertiesGeneratorTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testHelp(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
-      throws Exception {
+  void help(@SysErr Capturable systemErr, @SysOut Capturable systemOut) throws Exception {
     JavadocPropertiesGenerator.main("-h");
     assertWithMessage("Unexpected error log").that(systemErr.getCapturedData()).isEqualTo("");
     assertWithMessage("Unexpected output log").that(systemOut.getCapturedData()).isEqualTo(USAGE);
   }
 
   @Test
-  public void testJavadocParseError() throws Exception {
+  void javadocParseError() throws Exception {
     final String path = getPath("InputJavadocPropertiesGeneratorJavadocParseError.java");
     try {
       JavadocPropertiesGenerator.main(path, "--destfile", DESTFILE_ABSOLUTE_PATH);
@@ -278,7 +272,7 @@ public class JavadocPropertiesGeneratorTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testNotImplementedTag() throws Exception {
+  void notImplementedTag() throws Exception {
     final String path = getPath("InputJavadocPropertiesGeneratorNotImplementedTag.java");
     try {
       JavadocPropertiesGenerator.main(path, "--destfile", DESTFILE_ABSOLUTE_PATH);
@@ -293,7 +287,7 @@ public class JavadocPropertiesGeneratorTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testParseError() throws Exception {
+  void parseError() throws Exception {
     final String path = getNonCompilablePath("InputJavadocPropertiesGeneratorParseError.java");
     try {
       JavadocPropertiesGenerator.main(path, "--destfile", DESTFILE_ABSOLUTE_PATH);
@@ -315,8 +309,8 @@ public class JavadocPropertiesGeneratorTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetFirstJavadocSentence(
-      @SysErr Capturable systemErr, @SysOut Capturable systemOut) throws Exception {
+  void getFirstJavadocSentence(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
+      throws Exception {
     final String expectedContent = "EOF1=First Javadoc Sentence.";
 
     JavadocPropertiesGenerator.main(
@@ -325,7 +319,7 @@ public class JavadocPropertiesGeneratorTest extends AbstractPathTestSupport {
         DESTFILE_ABSOLUTE_PATH);
     assertWithMessage("Unexpected error log").that(systemErr.getCapturedData()).isEqualTo("");
     assertWithMessage("Unexpected output log").that(systemOut.getCapturedData()).isEqualTo("");
-    final String fileContent = FileUtils.readFileToString(DESTFILE, StandardCharsets.UTF_8);
+    final String fileContent = FileUtils.readFileToString(DESTFILE, UTF_8);
     assertWithMessage("File content is not expected")
         .that(fileContent.trim())
         .isEqualTo(expectedContent.trim());
--- a/src/test/java/com/puppycrawl/tools/checkstyle/LocalizedMessageTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/LocalizedMessageTest.java
@@ -44,13 +44,13 @@ import org.junitpioneer.jupiter.DefaultLocale;
  * @noinspectionreason ClassLoaderInstantiation - Custom class loader is needed to pass URLs for
  *     testing
  */
-public class LocalizedMessageTest {
+final class LocalizedMessageTest {
 
   private static final Locale DEFAULT_LOCALE = Locale.ENGLISH;
 
   @DefaultLocale("en")
   @Test
-  public void testNullArgs() {
+  void nullArgs() {
     final LocalizedMessage messageClass =
         new LocalizedMessage(
             Definitions.CHECKSTYLE_BUNDLE,
@@ -71,7 +71,7 @@ public class LocalizedMessageTest {
   }
 
   @Test
-  public void testBundleReloadUrlNull() throws IOException {
+  void bundleReloadUrlNull() throws IOException {
     final Utf8Control control = new Utf8Control();
     final ResourceBundle bundle =
         control.newBundle(
@@ -93,7 +93,7 @@ public class LocalizedMessageTest {
    * @noinspectionreason IOResourceOpenedButNotSafelyClosed - no need to close resources in testing
    */
   @Test
-  public void testBundleReloadUrlNotNull() throws IOException {
+  void bundleReloadUrlNotNull() throws IOException {
     final AtomicBoolean closed = new AtomicBoolean();
 
     final InputStream inputStream =
@@ -157,7 +157,7 @@ public class LocalizedMessageTest {
    * @noinspectionreason IOResourceOpenedButNotSafelyClosed - no need to close resources in testing
    */
   @Test
-  public void testBundleReloadUrlNotNullFalseReload() throws IOException {
+  void bundleReloadUrlNotNullFalseReload() throws IOException {
     final AtomicBoolean closed = new AtomicBoolean();
 
     final InputStream inputStream =
@@ -214,7 +214,7 @@ public class LocalizedMessageTest {
   }
 
   @Test
-  public void testBundleReloadUrlNotNullStreamNull() throws IOException {
+  void bundleReloadUrlNotNullStreamNull() throws IOException {
     final URL url =
         new URL(
             "test",
@@ -241,7 +241,7 @@ public class LocalizedMessageTest {
 
   /** Verifies that the language specified with the system property {@code user.language} exists. */
   @Test
-  public void testLanguageIsValid() {
+  void languageIsValid() {
     final String language = DEFAULT_LOCALE.getLanguage();
     assumeFalse(language.isEmpty(), "Locale not set");
     assertWithMessage("Invalid language")
@@ -252,14 +252,14 @@ public class LocalizedMessageTest {
 
   /** Verifies that the country specified with the system property {@code user.country} exists. */
   @Test
-  public void testCountryIsValid() {
+  void countryIsValid() {
     final String country = DEFAULT_LOCALE.getCountry();
     assumeFalse(country.isEmpty(), "Locale not set");
     assertWithMessage("Invalid country").that(Locale.getISOCountries()).asList().contains(country);
   }
 
   @Test
-  public void testMessageInFrench() {
+  void messageInFrench() {
     final LocalizedMessage violation = createSampleViolation();
     LocalizedMessage.setLocale(Locale.FRENCH);
 
@@ -270,7 +270,7 @@ public class LocalizedMessageTest {
 
   @DefaultLocale("fr")
   @Test
-  public void testEnforceEnglishLanguageBySettingUnitedStatesLocale() {
+  void enforceEnglishLanguageBySettingUnitedStatesLocale() {
     LocalizedMessage.setLocale(Locale.US);
     final LocalizedMessage violation = createSampleViolation();
 
@@ -281,7 +281,7 @@ public class LocalizedMessageTest {
 
   @DefaultLocale("fr")
   @Test
-  public void testEnforceEnglishLanguageBySettingRootLocale() {
+  void enforceEnglishLanguageBySettingRootLocale() {
     LocalizedMessage.setLocale(Locale.ROOT);
     final LocalizedMessage violation = createSampleViolation();
 
@@ -298,7 +298,7 @@ public class LocalizedMessageTest {
   }
 
   @AfterEach
-  public void tearDown() {
+  void tearDown() {
     LocalizedMessage.setLocale(DEFAULT_LOCALE);
   }
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/MainTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/MainTest.java
@@ -22,6 +22,8 @@ package com.puppycrawl.tools.checkstyle;
 import static com.google.common.truth.Truth.assertWithMessage;
 import static com.puppycrawl.tools.checkstyle.AbstractPathTestSupport.addEndOfLine;
 import static com.puppycrawl.tools.checkstyle.internal.utils.TestUtil.isUtilsClassHasPrivateConstructor;
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static java.util.stream.Collectors.joining;
 import static org.junit.jupiter.api.Assumptions.assumeTrue;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.mockStatic;
@@ -40,7 +42,6 @@ import java.io.File;
 import java.io.IOException;
 import java.io.PrintStream;
 import java.lang.reflect.Method;
-import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
@@ -51,7 +52,6 @@ import java.util.logging.Handler;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 import org.itsallcode.io.Capturable;
 import org.itsallcode.junit.sysextensions.SystemErrGuard;
 import org.itsallcode.junit.sysextensions.SystemErrGuard.SysErr;
@@ -65,7 +65,7 @@ import org.mockito.MockedStatic;
 import org.mockito.Mockito;
 
 @ExtendWith({SystemErrGuard.class, SystemOutGuard.class})
-public class MainTest {
+final class MainTest {
 
   private static final String SHORT_USAGE =
       String.format(
@@ -222,7 +222,7 @@ public class MainTest {
    * @param systemOut wrapper for {@code System.out}
    */
   @BeforeEach
-  public void setUp(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void setUp(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     systemErr.captureMuted();
     systemOut.captureMuted();
 
@@ -247,14 +247,14 @@ public class MainTest {
   }
 
   @Test
-  public void testIsProperUtilsClass() throws ReflectiveOperationException {
+  void isProperUtilsClass() throws ReflectiveOperationException {
     assertWithMessage("Constructor is not private")
         .that(isUtilsClassHasPrivateConstructor(Main.class))
         .isTrue();
   }
 
   @Test
-  public void testVersionPrint(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void versionPrint(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     assertMainReturnCode(0, "-V");
     assertWithMessage("Unexpected output log")
         .that(systemOut.getCapturedData())
@@ -265,7 +265,7 @@ public class MainTest {
   }
 
   @Test
-  public void testUsageHelpPrint(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void usageHelpPrint(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     assertMainReturnCode(0, "-h");
     assertWithMessage("Unexpected output log").that(systemOut.getCapturedData()).isEqualTo(USAGE);
     assertWithMessage("Unexpected system error log")
@@ -274,7 +274,7 @@ public class MainTest {
   }
 
   @Test
-  public void testWrongArgument(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void wrongArgument(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     // need to specify a file:
     // <files> is defined as a required positional param;
     // picocli verifies required parameters before checking unknown options
@@ -287,8 +287,7 @@ public class MainTest {
   }
 
   @Test
-  public void testWrongArgumentMissingFiles(
-      @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void wrongArgumentMissingFiles(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     assertMainReturnCode(-1, "-q");
     // files is defined as a required positional param;
     // picocli verifies required parameters before checking unknown options
@@ -300,7 +299,7 @@ public class MainTest {
   }
 
   @Test
-  public void testNoConfigSpecified(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void noConfigSpecified(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     assertMainReturnCode(-1, getPath("InputMain.java"));
     assertWithMessage("Unexpected output log")
         .that(systemOut.getCapturedData())
@@ -311,8 +310,7 @@ public class MainTest {
   }
 
   @Test
-  public void testNonExistentTargetFile(
-      @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void nonExistentTargetFile(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     assertMainReturnCode(-1, "-c", "/google_checks.xml", "NonExistentFile.java");
     assertWithMessage("Unexpected output log")
         .that(systemOut.getCapturedData())
@@ -323,7 +321,7 @@ public class MainTest {
   }
 
   @Test
-  public void testExistingTargetFileButWithoutReadAccess(
+  void existingTargetFileButWithoutReadAccess(
       @SysErr Capturable systemErr, @SysOut Capturable systemOut) throws IOException {
     final File file =
         File.createTempFile("testExistingTargetFileButWithoutReadAccess", null, temporaryFolder);
@@ -342,8 +340,7 @@ public class MainTest {
   }
 
   @Test
-  public void testNonExistentConfigFile(
-      @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void nonExistentConfigFile(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     assertMainReturnCode(
         -1, "-c", "src/main/resources/non_existent_config.xml", getPath("InputMain.java"));
     assertWithMessage("Unexpected output log")
@@ -358,8 +355,7 @@ public class MainTest {
   }
 
   @Test
-  public void testNonExistentOutputFormat(
-      @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void nonExistentOutputFormat(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     assertMainReturnCode(-1, "-c", "/google_checks.xml", "-f", "xmlp", getPath("InputMain.java"));
     assertWithMessage("Unexpected output log").that(systemOut.getCapturedData()).isEqualTo("");
     assertWithMessage("Unexpected system error log")
@@ -372,7 +368,7 @@ public class MainTest {
   }
 
   @Test
-  public void testNonExistentClass(@SysErr Capturable systemErr) {
+  void nonExistentClass(@SysErr Capturable systemErr) {
     assertMainReturnCode(
         -2, "-c", getPath("InputMainConfig-non-existent-classname.xml"), getPath("InputMain.java"));
     final String cause =
@@ -384,7 +380,7 @@ public class MainTest {
   }
 
   @Test
-  public void testExistingTargetFile(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void existingTargetFile(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     assertMainReturnCode(
         0, "-c", getPath("InputMainConfig-classname.xml"), getPath("InputMain.java"));
     assertWithMessage("Unexpected output log")
@@ -396,8 +392,8 @@ public class MainTest {
   }
 
   @Test
-  public void testExistingTargetFileXmlOutput(
-      @SysErr Capturable systemErr, @SysOut Capturable systemOut) throws IOException {
+  void existingTargetFileXmlOutput(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
+      throws IOException {
     assertMainReturnCode(
         0, "-c", getPath("InputMainConfig-classname.xml"), "-f", "xml", getPath("InputMain.java"));
     final String expectedPath = getFilePath("InputMain.java");
@@ -425,8 +421,7 @@ public class MainTest {
    * @param systemOut the system output stream
    */
   @Test
-  public void testNonClosedSystemStreams(
-      @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void nonClosedSystemStreams(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     try (ShouldNotBeClosedStream stream = new ShouldNotBeClosedStream()) {
       System.setOut(stream);
       System.setErr(stream);
@@ -456,7 +451,7 @@ public class MainTest {
    * @throws Exception if there is an error.
    */
   @Test
-  public void testGetOutputStreamOptionsMethod() throws Exception {
+  void getOutputStreamOptionsMethod() throws Exception {
     final Path path = new File(getPath("InputMain.java")).toPath();
     final OutputStreamOptions option =
         TestUtil.invokeStaticMethod(Main.class, "getOutputStreamOptions", path);
@@ -466,8 +461,7 @@ public class MainTest {
   }
 
   @Test
-  public void testExistingTargetFilePlainOutput(
-      @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void existingTargetFilePlainOutput(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     assertMainReturnCode(
         0,
         "-c",
@@ -484,8 +478,8 @@ public class MainTest {
   }
 
   @Test
-  public void testExistingTargetFileWithViolations(
-      @SysErr Capturable systemErr, @SysOut Capturable systemOut) throws IOException {
+  void existingTargetFileWithViolations(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
+      throws IOException {
     assertMainReturnCode(
         0, "-c", getPath("InputMainConfig-classname2.xml"), getPath("InputMain.java"));
     final Violation invalidPatternMessageMain =
@@ -529,7 +523,7 @@ public class MainTest {
   }
 
   @Test
-  public void testViolationsByGoogleAndXpathSuppressions(
+  void violationsByGoogleAndXpathSuppressions(
       @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     System.setProperty(
         "org.checkstyle.google.suppressionxpathfilter.config",
@@ -545,7 +539,7 @@ public class MainTest {
   }
 
   @Test
-  public void testViolationsByGoogleAndSuppressions(
+  void violationsByGoogleAndSuppressions(
       @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     System.setProperty(
         "org.checkstyle.google.suppressionfilter.config",
@@ -561,8 +555,8 @@ public class MainTest {
   }
 
   @Test
-  public void testExistingTargetFileWithError(
-      @SysErr Capturable systemErr, @SysOut Capturable systemOut) throws Exception {
+  void existingTargetFileWithError(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
+      throws Exception {
     assertMainReturnCode(
         2, "-c", getPath("InputMainConfig-classname2-error.xml"), getPath("InputMain.java"));
     final Violation errorCounterTwoMessage =
@@ -622,8 +616,8 @@ public class MainTest {
    * @throws Exception should not throw anything
    */
   @Test
-  public void testExistingTargetFileWithOneError(
-      @SysErr Capturable systemErr, @SysOut Capturable systemOut) throws Exception {
+  void existingTargetFileWithOneError(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
+      throws Exception {
     assertMainReturnCode(
         1, "-c", getPath("InputMainConfig-classname2-error.xml"), getPath("InputMain1.java"));
     final Violation errorCounterTwoMessage =
@@ -662,7 +656,7 @@ public class MainTest {
   }
 
   @Test
-  public void testExistingTargetFileWithOneErrorAgainstSunCheck(
+  void existingTargetFileWithOneErrorAgainstSunCheck(
       @SysErr Capturable systemErr, @SysOut Capturable systemOut) throws Exception {
     assertMainReturnCode(1, "-c", "/sun_checks.xml", getPath("InputMain1.java"));
     final Violation errorCounterTwoMessage =
@@ -697,7 +691,7 @@ public class MainTest {
   }
 
   @Test
-  public void testExistentTargetFilePlainOutputToNonExistentFile(
+  void existentTargetFilePlainOutputToNonExistentFile(
       @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     assertMainReturnCode(
         0,
@@ -715,7 +709,7 @@ public class MainTest {
   }
 
   @Test
-  public void testExistingTargetFilePlainOutputToFile(
+  void existingTargetFilePlainOutputToFile(
       @SysErr Capturable systemErr, @SysOut Capturable systemOut) throws Exception {
     final String outputFile =
         File.createTempFile("file", ".output", temporaryFolder).getCanonicalPath();
@@ -736,7 +730,7 @@ public class MainTest {
   }
 
   @Test
-  public void testCreateNonExistentOutputFile() throws IOException {
+  void createNonExistentOutputFile() throws IOException {
     final String outputFile = new File(temporaryFolder, "nonexistent.out").getCanonicalPath();
     assertWithMessage("File must not exist").that(new File(outputFile).exists()).isFalse();
     assertMainReturnCode(
@@ -752,7 +746,7 @@ public class MainTest {
   }
 
   @Test
-  public void testExistingTargetFilePlainOutputProperties(
+  void existingTargetFilePlainOutputProperties(
       @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     assertMainReturnCode(
         0,
@@ -770,7 +764,7 @@ public class MainTest {
   }
 
   @Test
-  public void testPropertyFileWithPropertyChaining(
+  void propertyFileWithPropertyChaining(
       @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     assertMainReturnCode(
         0,
@@ -789,7 +783,7 @@ public class MainTest {
   }
 
   @Test
-  public void testPropertyFileWithPropertyChainingUndefinedProperty(
+  void propertyFileWithPropertyChainingUndefinedProperty(
       @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     assertMainReturnCode(
         -2,
@@ -806,7 +800,7 @@ public class MainTest {
   }
 
   @Test
-  public void testExistingTargetFilePlainOutputNonexistentProperties(
+  void existingTargetFilePlainOutputNonexistentProperties(
       @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     assertMainReturnCode(
         -1,
@@ -824,7 +818,7 @@ public class MainTest {
   }
 
   @Test
-  public void testExistingIncorrectConfigFile(@SysErr Capturable systemErr) {
+  void existingIncorrectConfigFile(@SysErr Capturable systemErr) {
     assertMainReturnCode(
         -2, "-c", getPath("InputMainConfig-Incorrect.xml"), getPath("InputMain.java"));
     final String errorOutput =
@@ -836,7 +830,7 @@ public class MainTest {
   }
 
   @Test
-  public void testExistingIncorrectChildrenInConfigFile(@SysErr Capturable systemErr) {
+  void existingIncorrectChildrenInConfigFile(@SysErr Capturable systemErr) {
     assertMainReturnCode(
         -2, "-c", getPath("InputMainConfig-incorrectChildren.xml"), getPath("InputMain.java"));
     final String errorOutput =
@@ -849,7 +843,7 @@ public class MainTest {
   }
 
   @Test
-  public void testExistingIncorrectChildrenInConfigFile2(@SysErr Capturable systemErr) {
+  void existingIncorrectChildrenInConfigFile2(@SysErr Capturable systemErr) {
     assertMainReturnCode(
         -2, "-c", getPath("InputMainConfig-incorrectChildren2.xml"), getPath("InputMain.java"));
     final String errorOutput =
@@ -863,7 +857,7 @@ public class MainTest {
   }
 
   @Test
-  public void testLoadPropertiesIoException() throws Exception {
+  void loadPropertiesIoException() throws Exception {
     final Class<?>[] param = new Class<?>[1];
     param[0] = File.class;
     final Class<?> cliOptionsClass = Class.forName(Main.class.getName());
@@ -905,8 +899,8 @@ public class MainTest {
   }
 
   @Test
-  public void testExistingDirectoryWithViolations(
-      @SysErr Capturable systemErr, @SysOut Capturable systemOut) throws IOException {
+  void existingDirectoryWithViolations(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
+      throws IOException {
     // we just reference there all violations
     final String[][] outputValues = {
       {"InputMainComplexityOverflow", "1", "172"},
@@ -953,7 +947,7 @@ public class MainTest {
    *     does not require serialization
    */
   @Test
-  public void testListFilesNotFile() throws Exception {
+  void listFilesNotFile() throws Exception {
     final File fileMock =
         new File("") {
           private static final long serialVersionUID = 1L;
@@ -987,7 +981,7 @@ public class MainTest {
    *     does not require serialization
    */
   @Test
-  public void testListFilesDirectoryWithNull() throws Exception {
+  void listFilesDirectoryWithNull() throws Exception {
     final File[] nullResult = null;
     final File fileMock =
         new File("") {
@@ -1015,7 +1009,7 @@ public class MainTest {
   }
 
   @Test
-  public void testFileReferenceDuringException(@SysErr Capturable systemErr) {
+  void fileReferenceDuringException(@SysErr Capturable systemErr) {
     // We put xml as source to cause parse exception
     assertMainReturnCode(
         -2,
@@ -1033,7 +1027,7 @@ public class MainTest {
   }
 
   @Test
-  public void testRemoveLexerDefaultErrorListener(@SysErr Capturable systemErr) {
+  void removeLexerDefaultErrorListener(@SysErr Capturable systemErr) {
     assertMainReturnCode(-2, "-t", getNonCompilablePath("InputMainIncorrectClass.java"));
 
     assertWithMessage("First line of exception message should not contain lexer error.")
@@ -1042,7 +1036,7 @@ public class MainTest {
   }
 
   @Test
-  public void testRemoveParserDefaultErrorListener(@SysErr Capturable systemErr) {
+  void removeParserDefaultErrorListener(@SysErr Capturable systemErr) {
     assertMainReturnCode(-2, "-t", getNonCompilablePath("InputMainIncorrectClass.java"));
     final String capturedData = systemErr.getCapturedData();
 
@@ -1057,8 +1051,7 @@ public class MainTest {
   }
 
   @Test
-  public void testPrintTreeOnMoreThanOneFile(
-      @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void printTreeOnMoreThanOneFile(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     assertMainReturnCode(-1, "-t", getPath(""));
     assertWithMessage("Unexpected output log")
         .that(systemOut.getCapturedData())
@@ -1069,7 +1062,7 @@ public class MainTest {
   }
 
   @Test
-  public void testPrintTreeOption(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void printTreeOption(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     final String expected =
         addEndOfLine(
             "COMPILATION_UNIT -> COMPILATION_UNIT [1:0]",
@@ -1111,7 +1104,7 @@ public class MainTest {
   }
 
   @Test
-  public void testPrintXpathOption(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void printXpathOption(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     final String expected =
         addEndOfLine(
             "COMPILATION_UNIT -> COMPILATION_UNIT [1:0]",
@@ -1136,8 +1129,7 @@ public class MainTest {
   }
 
   @Test
-  public void testPrintXpathCommentNode(
-      @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void printXpathCommentNode(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     final String expected =
         addEndOfLine(
             "COMPILATION_UNIT -> COMPILATION_UNIT [1:0]",
@@ -1159,8 +1151,7 @@ public class MainTest {
   }
 
   @Test
-  public void testPrintXpathNodeParentNull(
-      @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void printXpathNodeParentNull(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     final String expected = addEndOfLine("COMPILATION_UNIT -> COMPILATION_UNIT [1:0]");
     assertMainReturnCode(0, "-b", "/COMPILATION_UNIT", getPath("InputMainXPath.java"));
     assertWithMessage("Unexpected output log")
@@ -1172,7 +1163,7 @@ public class MainTest {
   }
 
   @Test
-  public void testPrintXpathFullOption(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void printXpathFullOption(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     final String expected =
         addEndOfLine(
             "COMPILATION_UNIT -> COMPILATION_UNIT [1:0]",
@@ -1194,7 +1185,7 @@ public class MainTest {
   }
 
   @Test
-  public void testPrintXpathTwoResults(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void printXpathTwoResults(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     final String expected =
         addEndOfLine(
             "COMPILATION_UNIT -> COMPILATION_UNIT [1:0]",
@@ -1220,7 +1211,7 @@ public class MainTest {
   }
 
   @Test
-  public void testPrintXpathInvalidXpath(@SysErr Capturable systemErr) throws Exception {
+  void printXpathInvalidXpath(@SysErr Capturable systemErr) throws Exception {
     final String invalidXpath =
         "\\/COMPILATION_UNIT/CLASS_DEF[./IDENT[@text='Two']]" + "//METHOD_DEF";
     final String filePath = getFilePath("InputMainXPath.java");
@@ -1238,8 +1229,7 @@ public class MainTest {
   }
 
   @Test
-  public void testPrintTreeCommentsOption(
-      @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void printTreeCommentsOption(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     final String expected =
         addEndOfLine(
             "COMPILATION_UNIT -> COMPILATION_UNIT [1:0]",
@@ -1293,7 +1283,7 @@ public class MainTest {
    * @noinspectionreason RedundantThrows - false positive
    */
   @Test
-  public void testPrintTreeJavadocOption(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
+  void printTreeJavadocOption(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
       throws IOException {
     final String expected =
         Files.readString(Paths.get(getPath("InputMainExpectedInputJavadocComment.txt")))
@@ -1311,8 +1301,7 @@ public class MainTest {
   }
 
   @Test
-  public void testPrintSuppressionOption(
-      @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void printSuppressionOption(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     final String expected =
         addEndOfLine(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT[@text='InputMainSuppressionsStringPrinter']]",
@@ -1331,7 +1320,7 @@ public class MainTest {
   }
 
   @Test
-  public void testPrintSuppressionAndTabWidthOption(
+  void printSuppressionAndTabWidthOption(
       @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     final String expected =
         addEndOfLine(
@@ -1363,7 +1352,7 @@ public class MainTest {
   }
 
   @Test
-  public void testPrintSuppressionConflictingOptionsTvsC(
+  void printSuppressionConflictingOptionsTvsC(
       @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     assertMainReturnCode(-1, "-c", "/google_checks.xml", getPath(""), "-s", "2:4");
     assertWithMessage("Unexpected output log")
@@ -1375,7 +1364,7 @@ public class MainTest {
   }
 
   @Test
-  public void testPrintSuppressionConflictingOptionsTvsP(
+  void printSuppressionConflictingOptionsTvsP(
       @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     assertMainReturnCode(
         -1, "-p", getPath("InputMainMycheckstyle.properties"), "-s", "2:4", getPath(""));
@@ -1388,7 +1377,7 @@ public class MainTest {
   }
 
   @Test
-  public void testPrintSuppressionConflictingOptionsTvsF(
+  void printSuppressionConflictingOptionsTvsF(
       @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     assertMainReturnCode(-1, "-f", "plain", "-s", "2:4", getPath(""));
     assertWithMessage("Unexpected output log")
@@ -1400,7 +1389,7 @@ public class MainTest {
   }
 
   @Test
-  public void testPrintSuppressionConflictingOptionsTvsO(
+  void printSuppressionConflictingOptionsTvsO(
       @SysErr Capturable systemErr, @SysOut Capturable systemOut) throws IOException {
     final String outputPath = new File(temporaryFolder, "file.output").getCanonicalPath();
 
@@ -1414,7 +1403,7 @@ public class MainTest {
   }
 
   @Test
-  public void testPrintSuppressionOnMoreThanOneFile(
+  void printSuppressionOnMoreThanOneFile(
       @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     assertMainReturnCode(-1, "-s", "2:4", getPath(""), getPath(""));
     assertWithMessage("Unexpected output log")
@@ -1427,7 +1416,7 @@ public class MainTest {
   }
 
   @Test
-  public void testGenerateXpathSuppressionOptionOne(
+  void generateXpathSuppressionOptionOne(
       @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     final String expected =
         addEndOfLine(
@@ -1546,7 +1535,7 @@ public class MainTest {
   }
 
   @Test
-  public void testGenerateXpathSuppressionOptionTwo(
+  void generateXpathSuppressionOptionTwo(
       @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     final String expected =
         addEndOfLine(
@@ -1593,7 +1582,7 @@ public class MainTest {
   }
 
   @Test
-  public void testGenerateXpathSuppressionOptionEmptyConfig(
+  void generateXpathSuppressionOptionEmptyConfig(
       @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     final String expected = "";
 
@@ -1612,8 +1601,7 @@ public class MainTest {
   }
 
   @Test
-  public void testGenerateXpathSuppressionOptionCustomOutput(@SysErr Capturable systemErr)
-      throws IOException {
+  void generateXpathSuppressionOptionCustomOutput(@SysErr Capturable systemErr) throws IOException {
     final String expected =
         addEndOfLine(
             "<?xml version=\"1.0\" encoding=\"UTF-8\"?>",
@@ -1639,7 +1627,7 @@ public class MainTest {
         "--generate-xpath-suppression",
         getPath("InputMainGenerateXpathSuppressionsTabWidth.java"));
     try (BufferedReader br = Files.newBufferedReader(file.toPath())) {
-      final String fileContent = br.lines().collect(Collectors.joining(EOL, "", EOL));
+      final String fileContent = br.lines().collect(joining(EOL, "", EOL));
       assertWithMessage("Unexpected output log").that(fileContent).isEqualTo(expected);
       assertWithMessage("Unexpected system error log")
           .that(systemErr.getCapturedData())
@@ -1648,7 +1636,7 @@ public class MainTest {
   }
 
   @Test
-  public void testGenerateXpathSuppressionOptionDefaultTabWidth(
+  void generateXpathSuppressionOptionDefaultTabWidth(
       @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     final String expected =
         addEndOfLine(
@@ -1681,7 +1669,7 @@ public class MainTest {
   }
 
   @Test
-  public void testGenerateXpathSuppressionOptionCustomTabWidth(
+  void generateXpathSuppressionOptionCustomTabWidth(
       @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     final String expected = "";
 
@@ -1711,7 +1699,7 @@ public class MainTest {
    * @noinspectionreason RedundantThrows - false positive
    */
   @Test
-  public void testPrintFullTreeOption(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
+  void printFullTreeOption(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
       throws IOException {
     final String expected =
         Files.readString(
@@ -1730,8 +1718,7 @@ public class MainTest {
   }
 
   @Test
-  public void testConflictingOptionsTvsC(
-      @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void conflictingOptionsTvsC(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     assertMainReturnCode(-1, "-c", "/google_checks.xml", "-t", getPath(""));
     assertWithMessage("Unexpected output log")
         .that(systemOut.getCapturedData())
@@ -1742,8 +1729,7 @@ public class MainTest {
   }
 
   @Test
-  public void testConflictingOptionsTvsP(
-      @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void conflictingOptionsTvsP(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     assertMainReturnCode(-1, "-p", getPath("InputMainMycheckstyle.properties"), "-t", getPath(""));
     assertWithMessage("Unexpected output log")
         .that(systemOut.getCapturedData())
@@ -1754,8 +1740,7 @@ public class MainTest {
   }
 
   @Test
-  public void testConflictingOptionsTvsF(
-      @SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void conflictingOptionsTvsF(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     assertMainReturnCode(-1, "-f", "plain", "-t", getPath(""));
     assertWithMessage("Unexpected output log")
         .that(systemOut.getCapturedData())
@@ -1766,7 +1751,7 @@ public class MainTest {
   }
 
   @Test
-  public void testConflictingOptionsTvsS(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
+  void conflictingOptionsTvsS(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
       throws IOException {
     final String outputPath = new File(temporaryFolder, "file.output").getCanonicalPath();
 
@@ -1780,7 +1765,7 @@ public class MainTest {
   }
 
   @Test
-  public void testConflictingOptionsTvsO(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
+  void conflictingOptionsTvsO(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
       throws IOException {
     final String outputPath = new File(temporaryFolder, "file.output").getCanonicalPath();
 
@@ -1794,7 +1779,7 @@ public class MainTest {
   }
 
   @Test
-  public void testDebugOption(@SysErr Capturable systemErr) {
+  void debugOption(@SysErr Capturable systemErr) {
     assertMainReturnCode(0, "-c", "/google_checks.xml", getPath("InputMain.java"), "-d");
     assertWithMessage("Unexpected system error log")
         .that(systemErr.getCapturedData())
@@ -1802,7 +1787,7 @@ public class MainTest {
   }
 
   @Test
-  public void testExcludeOption(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
+  void excludeOption(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
       throws IOException {
     final String filePath = getFilePath("");
     assertMainReturnCode(-1, "-c", "/google_checks.xml", filePath, "-e", filePath);
@@ -1815,7 +1800,7 @@ public class MainTest {
   }
 
   @Test
-  public void testExcludeOptionFile(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
+  void excludeOptionFile(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
       throws IOException {
     final String filePath = getFilePath("InputMain.java");
     assertMainReturnCode(-1, "-c", "/google_checks.xml", filePath, "-e", filePath);
@@ -1828,7 +1813,7 @@ public class MainTest {
   }
 
   @Test
-  public void testExcludeRegexpOption(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
+  void excludeRegexpOption(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
       throws IOException {
     final String filePath = getFilePath("");
     assertMainReturnCode(-1, "-c", "/google_checks.xml", filePath, "-x", ".");
@@ -1839,8 +1824,8 @@ public class MainTest {
   }
 
   @Test
-  public void testExcludeRegexpOptionFile(
-      @SysErr Capturable systemErr, @SysOut Capturable systemOut) throws IOException {
+  void excludeRegexpOptionFile(@SysErr Capturable systemErr, @SysOut Capturable systemOut)
+      throws IOException {
     final String filePath = getFilePath("InputMain.java");
     assertMainReturnCode(-1, "-c", "/google_checks.xml", filePath, "-x", ".");
     assertWithMessage("Unexpected output log")
@@ -1849,9 +1834,9 @@ public class MainTest {
     assertWithMessage("Unexpected output log").that(systemErr.getCapturedData()).isEqualTo("");
   }
 
-  @Test
   @SuppressWarnings("unchecked")
-  public void testExcludeDirectoryNotMatch() throws Exception {
+  @Test
+  void excludeDirectoryNotMatch() throws Exception {
     final Class<?> optionsClass = Class.forName(Main.class.getName());
     final Method method = optionsClass.getDeclaredMethod("listFiles", File.class, List.class);
     method.setAccessible(true);
@@ -1863,7 +1848,7 @@ public class MainTest {
   }
 
   @Test
-  public void testCustomRootModule(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void customRootModule(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     TestRootModuleChecker.reset();
 
     assertMainReturnCode(
@@ -1879,7 +1864,7 @@ public class MainTest {
   }
 
   @Test
-  public void testCustomSimpleRootModule(@SysErr Capturable systemErr) {
+  void customSimpleRootModule(@SysErr Capturable systemErr) {
     TestRootModuleChecker.reset();
     assertMainReturnCode(
         -2,
@@ -1908,8 +1893,7 @@ public class MainTest {
   }
 
   @Test
-  public void testExceptionOnExecuteIgnoredModuleWithUnknownModuleName(
-      @SysErr Capturable systemErr) {
+  void exceptionOnExecuteIgnoredModuleWithUnknownModuleName(@SysErr Capturable systemErr) {
     assertMainReturnCode(
         -2,
         "-c",
@@ -1925,8 +1909,7 @@ public class MainTest {
   }
 
   @Test
-  public void testExceptionOnExecuteIgnoredModuleWithBadPropertyValue(
-      @SysErr Capturable systemErr) {
+  void exceptionOnExecuteIgnoredModuleWithBadPropertyValue(@SysErr Capturable systemErr) {
     assertMainReturnCode(
         -2,
         "-c",
@@ -1946,15 +1929,14 @@ public class MainTest {
   }
 
   @Test
-  public void testNoProblemOnExecuteIgnoredModuleWithBadPropertyValue(
-      @SysErr Capturable systemErr) {
+  void noProblemOnExecuteIgnoredModuleWithBadPropertyValue(@SysErr Capturable systemErr) {
     assertMainReturnCode(
         0, "-c", getPath("InputMainConfig-TypeName-bad-value.xml"), "", getPath("InputMain.java"));
     assertWithMessage("Unexpected system error log").that(systemErr.getCapturedData()).isEmpty();
   }
 
   @Test
-  public void testMissingFiles(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
+  void missingFiles(@SysErr Capturable systemErr, @SysOut Capturable systemOut) {
     assertMainReturnCode(-1);
     final String usage = "Missing required parameter: '<files>'" + EOL + SHORT_USAGE;
     assertWithMessage("Unexpected output log").that(systemOut.getCapturedData()).isEqualTo("");
@@ -1964,13 +1946,13 @@ public class MainTest {
   }
 
   @Test
-  public void testOutputFormatToStringLowercase() {
+  void outputFormatToStringLowercase() {
     assertWithMessage("expected xml").that(Main.OutputFormat.XML.toString()).isEqualTo("xml");
     assertWithMessage("expected plain").that(Main.OutputFormat.PLAIN.toString()).isEqualTo("plain");
   }
 
   @Test
-  public void testXmlOutputFormatCreateListener() throws IOException {
+  void xmlOutputFormatCreateListener() throws IOException {
     final ByteArrayOutputStream out = new ByteArrayOutputStream();
     final AuditListener listener =
         Main.OutputFormat.XML.createListener(out, OutputStreamOptions.CLOSE);
@@ -1978,7 +1960,7 @@ public class MainTest {
   }
 
   @Test
-  public void testSarifOutputFormatCreateListener() throws IOException {
+  void sarifOutputFormatCreateListener() throws IOException {
     final ByteArrayOutputStream out = new ByteArrayOutputStream();
     final AuditListener listener =
         Main.OutputFormat.SARIF.createListener(out, OutputStreamOptions.CLOSE);
@@ -1986,7 +1968,7 @@ public class MainTest {
   }
 
   @Test
-  public void testPlainOutputFormatCreateListener() throws IOException {
+  void plainOutputFormatCreateListener() throws IOException {
     final ByteArrayOutputStream out = new ByteArrayOutputStream();
     final AuditListener listener =
         Main.OutputFormat.PLAIN.createListener(out, OutputStreamOptions.CLOSE);
@@ -2025,7 +2007,7 @@ public class MainTest {
     private boolean isClosed;
 
     private ShouldNotBeClosedStream() {
-      super(new ByteArrayOutputStream(), false, StandardCharsets.UTF_8);
+      super(new ByteArrayOutputStream(), false, UTF_8);
     }
 
     @Override
--- a/src/test/java/com/puppycrawl/tools/checkstyle/MetadataGeneratorLoggerTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/MetadataGeneratorLoggerTest.java
@@ -31,10 +31,10 @@ import java.io.IOException;
 import java.io.OutputStream;
 import org.junit.jupiter.api.Test;
 
-public class MetadataGeneratorLoggerTest {
+final class MetadataGeneratorLoggerTest {
 
   @Test
-  public void testIgnoreSeverityLevel() {
+  void ignoreSeverityLevel() {
     final OutputStream outputStream = new ByteArrayOutputStream();
     final MetadataGeneratorLogger logger =
         new MetadataGeneratorLogger(outputStream, OutputStreamOptions.CLOSE);
@@ -59,7 +59,7 @@ public class MetadataGeneratorLoggerTest {
   }
 
   @Test
-  public void testAddException() {
+  void addException() {
     final OutputStream outputStream = new ByteArrayOutputStream();
     final MetadataGeneratorLogger logger =
         new MetadataGeneratorLogger(outputStream, OutputStreamOptions.CLOSE);
@@ -72,7 +72,7 @@ public class MetadataGeneratorLoggerTest {
   }
 
   @Test
-  public void testClose() throws IOException {
+  void close() throws IOException {
     try (CloseAndFlushTestByteArrayOutputStream outputStream =
         new CloseAndFlushTestByteArrayOutputStream()) {
       final MetadataGeneratorLogger logger =
@@ -83,7 +83,7 @@ public class MetadataGeneratorLoggerTest {
   }
 
   @Test
-  public void testCloseOutputStreamOptionNone() throws IOException {
+  void closeOutputStreamOptionNone() throws IOException {
     try (CloseAndFlushTestByteArrayOutputStream outputStream =
         new CloseAndFlushTestByteArrayOutputStream()) {
       final MetadataGeneratorLogger logger =
@@ -95,7 +95,7 @@ public class MetadataGeneratorLoggerTest {
   }
 
   @Test
-  public void testFlushStreams() throws Exception {
+  void flushStreams() throws Exception {
     try (CloseAndFlushTestByteArrayOutputStream outputStream =
         new CloseAndFlushTestByteArrayOutputStream()) {
       final MetadataGeneratorLogger logger =
--- a/src/test/java/com/puppycrawl/tools/checkstyle/PackageNamesLoaderTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/PackageNamesLoaderTest.java
@@ -20,8 +20,10 @@
 package com.puppycrawl.tools.checkstyle;
 
 import static com.google.common.truth.Truth.assertWithMessage;
-import static org.junit.jupiter.api.Assertions.assertThrows;
+import static java.util.Collections.emptyEnumeration;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
 import java.io.File;
 import java.io.IOException;
@@ -45,7 +47,7 @@ import org.xml.sax.SAXException;
  *     pretend these are loaded from the classpath though we can't add/change the files for testing.
  *     The class loader is nested in this class, so the custom class loader we are using is safe.
  */
-public class PackageNamesLoaderTest extends AbstractPathTestSupport {
+final class PackageNamesLoaderTest extends AbstractPathTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -53,26 +55,25 @@ public class PackageNamesLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testDefault() throws CheckstyleException {
+  void testDefault() throws CheckstyleException {
     final Set<String> packageNames =
         PackageNamesLoader.getPackageNames(Thread.currentThread().getContextClassLoader());
     assertWithMessage("pkgNames.length.").that(packageNames).isEmpty();
   }
 
   @Test
-  public void testNoPackages() throws Exception {
+  void noPackages() throws Exception {
     final Set<String> actualPackageNames =
-        PackageNamesLoader.getPackageNames(new TestUrlsClassLoader(Collections.emptyEnumeration()));
+        PackageNamesLoader.getPackageNames(new TestUrlsClassLoader(emptyEnumeration()));
 
     assertWithMessage("Invalid package names length.").that(actualPackageNames).isEmpty();
   }
 
   @Test
-  public void testPackagesFile() throws Exception {
+  void packagesFile() throws Exception {
     final Enumeration<URL> enumeration =
         Collections.enumeration(
-            Collections.singleton(
-                new File(getPath("InputPackageNamesLoaderFile.xml")).toURI().toURL()));
+            ImmutableSet.of(new File(getPath("InputPackageNamesLoaderFile.xml")).toURI().toURL()));
 
     final Set<String> actualPackageNames =
         PackageNamesLoader.getPackageNames(new TestUrlsClassLoader(enumeration));
@@ -107,10 +108,10 @@ public class PackageNamesLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testPackagesWithDots() throws Exception {
+  void packagesWithDots() throws Exception {
     final Enumeration<URL> enumeration =
         Collections.enumeration(
-            Collections.singleton(
+            ImmutableSet.of(
                 new File(getPath("InputPackageNamesLoaderWithDots.xml")).toURI().toURL()));
 
     final Set<String> actualPackageNames =
@@ -129,10 +130,10 @@ public class PackageNamesLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testPackagesWithDotsEx() throws Exception {
+  void packagesWithDotsEx() throws Exception {
     final Enumeration<URL> enumeration =
         Collections.enumeration(
-            Collections.singleton(
+            ImmutableSet.of(
                 new File(getPath("InputPackageNamesLoaderWithDotsEx.xml")).toURI().toURL()));
 
     final Set<String> actualPackageNames =
@@ -151,10 +152,10 @@ public class PackageNamesLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testPackagesWithSaxException() throws Exception {
+  void packagesWithSaxException() throws Exception {
     final Enumeration<URL> enumeration =
         Collections.enumeration(
-            Collections.singleton(
+            ImmutableSet.of(
                 new File(getPath("InputPackageNamesLoaderNotXml.java")).toURI().toURL()));
 
     try {
@@ -169,7 +170,7 @@ public class PackageNamesLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testPackagesWithIoException() throws Exception {
+  void packagesWithIoException() throws Exception {
     final URLConnection urlConnection =
         new URLConnection(null) {
           @Override
@@ -195,7 +196,7 @@ public class PackageNamesLoaderTest extends AbstractPathTestSupport {
               }
             });
 
-    final Enumeration<URL> enumeration = Collections.enumeration(Collections.singleton(url));
+    final Enumeration<URL> enumeration = Collections.enumeration(ImmutableSet.of(url));
 
     try {
       PackageNamesLoader.getPackageNames(new TestUrlsClassLoader(enumeration));
@@ -213,7 +214,7 @@ public class PackageNamesLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testPackagesWithIoExceptionGetResources() {
+  void packagesWithIoExceptionGetResources() {
     try {
       PackageNamesLoader.getPackageNames(new TestIoExceptionClassLoader());
       assertWithMessage("CheckstyleException is expected").fail();
@@ -229,21 +230,20 @@ public class PackageNamesLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testUnmodifiableCollection() throws Exception {
+  void unmodifiableCollection() throws Exception {
     final Set<String> actualPackageNames =
-        PackageNamesLoader.getPackageNames(new TestUrlsClassLoader(Collections.emptyEnumeration()));
+        PackageNamesLoader.getPackageNames(new TestUrlsClassLoader(emptyEnumeration()));
 
-    assertThrows(
-        UnsupportedOperationException.class,
-        () -> actualPackageNames.add("com.puppycrawl.tools.checkstyle.checks.modifier"));
+    assertThatThrownBy(
+            () -> actualPackageNames.add("com.puppycrawl.tools.checkstyle.checks.modifier"))
+        .isInstanceOf(UnsupportedOperationException.class);
   }
 
   @Test
-  public void testMapping() throws Exception {
+  void mapping() throws Exception {
     final Enumeration<URL> enumeration =
         Collections.enumeration(
-            Collections.singleton(
-                new File(getPath("InputPackageNamesLoader1.xml")).toURI().toURL()));
+            ImmutableSet.of(new File(getPath("InputPackageNamesLoader1.xml")).toURI().toURL()));
 
     final Set<String> actualPackageNames =
         PackageNamesLoader.getPackageNames(new TestUrlsClassLoader(enumeration));
@@ -252,11 +252,10 @@ public class PackageNamesLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testMapping2() throws Exception {
+  void mapping2() throws Exception {
     final Enumeration<URL> enumeration =
         Collections.enumeration(
-            Collections.singleton(
-                new File(getPath("InputPackageNamesLoader2.xml")).toURI().toURL()));
+            ImmutableSet.of(new File(getPath("InputPackageNamesLoader2.xml")).toURI().toURL()));
 
     final Set<String> actualPackageNames =
         PackageNamesLoader.getPackageNames(new TestUrlsClassLoader(enumeration));
--- a/src/test/java/com/puppycrawl/tools/checkstyle/PackageObjectFactoryTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/PackageObjectFactoryTest.java
@@ -30,9 +30,12 @@ import static com.puppycrawl.tools.checkstyle.PackageObjectFactory.NULL_PACKAGE_
 import static com.puppycrawl.tools.checkstyle.PackageObjectFactory.PACKAGE_SEPARATOR;
 import static com.puppycrawl.tools.checkstyle.PackageObjectFactory.STRING_SEPARATOR;
 import static com.puppycrawl.tools.checkstyle.PackageObjectFactory.UNABLE_TO_INSTANTIATE_EXCEPTION_MESSAGE;
+import static java.util.Collections.singleton;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.mockito.Mockito.mockStatic;
 
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck;
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
 import com.puppycrawl.tools.checkstyle.api.FileText;
@@ -47,7 +50,6 @@ import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.HashSet;
 import java.util.LinkedHashSet;
 import java.util.Map;
@@ -58,13 +60,13 @@ import org.mockito.MockedStatic;
 import org.mockito.Mockito;
 
 /** Enter a description of class PackageObjectFactoryTest.java. */
-public class PackageObjectFactoryTest {
+final class PackageObjectFactoryTest {
 
   private final PackageObjectFactory factory =
       new PackageObjectFactory(BASE_PACKAGE, Thread.currentThread().getContextClassLoader());
 
   @Test
-  public void testCtorNullLoaderException1() {
+  void ctorNullLoaderException1() {
     try {
       final Object test = new PackageObjectFactory(new HashSet<>(), null);
       assertWithMessage("Exception is expected but got " + test).fail();
@@ -76,7 +78,7 @@ public class PackageObjectFactoryTest {
   }
 
   @Test
-  public void testCtorNullLoaderException2() {
+  void ctorNullLoaderException2() {
     try {
       final Object test = new PackageObjectFactory("test", null);
       assertWithMessage("Exception is expected but got " + test).fail();
@@ -88,12 +90,12 @@ public class PackageObjectFactoryTest {
   }
 
   @Test
-  public void testCtorNullPackageException1() {
+  void ctorNullPackageException1() {
     final ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
     try {
       // XXX: Don't suggest `ImmutableSet.of(elem)` for nullable `elem`.
       @SuppressWarnings("ImmutableSetOf1")
-      final Object test = new PackageObjectFactory(Collections.singleton(null), classLoader);
+      final Object test = new PackageObjectFactory(singleton(null), classLoader);
       assertWithMessage("Exception is expected but got " + test).fail();
     } catch (IllegalArgumentException ex) {
       assertWithMessage("Invalid exception message")
@@ -103,7 +105,7 @@ public class PackageObjectFactoryTest {
   }
 
   @Test
-  public void testCtorNullPackageException2() {
+  void ctorNullPackageException2() {
     final ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
     try {
       final Object test = new PackageObjectFactory((String) null, classLoader);
@@ -116,14 +118,13 @@ public class PackageObjectFactoryTest {
   }
 
   @Test
-  public void testCtorNullPackageException3() {
+  void ctorNullPackageException3() {
     final ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
     try {
       // XXX: Don't suggest `ImmutableSet.of(elem)` for nullable `elem`.
       @SuppressWarnings("ImmutableSetOf1")
       final Object test =
-          new PackageObjectFactory(
-              Collections.singleton(null), classLoader, TRY_IN_ALL_REGISTERED_PACKAGES);
+          new PackageObjectFactory(singleton(null), classLoader, TRY_IN_ALL_REGISTERED_PACKAGES);
       assertWithMessage("Exception is expected but got " + test).fail();
     } catch (IllegalArgumentException ex) {
       assertWithMessage("Invalid exception message")
@@ -133,7 +134,7 @@ public class PackageObjectFactoryTest {
   }
 
   @Test
-  public void testMakeObjectFromName() throws CheckstyleException {
+  void makeObjectFromName() throws CheckstyleException {
     final Checker checker =
         (Checker) factory.createModule("com.puppycrawl.tools.checkstyle.Checker");
     assertWithMessage("Checker should not be null when creating module from name")
@@ -142,7 +143,7 @@ public class PackageObjectFactoryTest {
   }
 
   @Test
-  public void testMakeCheckFromName() {
+  void makeCheckFromName() {
     final String name = "com.puppycrawl.tools.checkstyle.checks.naming.ConstantName";
     try {
       factory.createModule(name);
@@ -162,7 +163,7 @@ public class PackageObjectFactoryTest {
   }
 
   @Test
-  public void testCreateModuleWithNonExistName() {
+  void createModuleWithNonExistName() {
     final String[] names = {
       "NonExistClassOne", "NonExistClassTwo",
     };
@@ -198,7 +199,7 @@ public class PackageObjectFactoryTest {
   }
 
   @Test
-  public void testCreateObjectFromMap() throws Exception {
+  void createObjectFromMap() throws Exception {
     final String moduleName = "Foo";
     final String name = moduleName + CHECK_SUFFIX;
     final String packageName = BASE_PACKAGE + ".packageobjectfactory.bar";
@@ -216,7 +217,7 @@ public class PackageObjectFactoryTest {
   }
 
   @Test
-  public void testCreateStandardModuleObjectFromMap() throws Exception {
+  void createStandardModuleObjectFromMap() throws Exception {
     final String moduleName = "TreeWalker";
     final String packageName = BASE_PACKAGE + ".packageobjectfactory.bar";
     final String fullName = BASE_PACKAGE + PACKAGE_SEPARATOR + moduleName;
@@ -229,7 +230,7 @@ public class PackageObjectFactoryTest {
   }
 
   @Test
-  public void testCreateStandardCheckModuleObjectFromMap() throws Exception {
+  void createStandardCheckModuleObjectFromMap() throws Exception {
     final String moduleName = "TypeName";
     final String packageName = BASE_PACKAGE + ".packageobjectfactory.bar";
     final String fullName =
@@ -250,7 +251,7 @@ public class PackageObjectFactoryTest {
   }
 
   @Test
-  public void testCreateObjectFromFullModuleNamesWithAmbiguousException() {
+  void createObjectFromFullModuleNamesWithAmbiguousException() {
     final String barPackage = BASE_PACKAGE + ".packageobjectfactory.bar";
     final String fooPackage = BASE_PACKAGE + ".packageobjectfactory.foo";
     final ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
@@ -284,7 +285,7 @@ public class PackageObjectFactoryTest {
   }
 
   @Test
-  public void testCreateObjectFromFullModuleNamesWithCantInstantiateException() {
+  void createObjectFromFullModuleNamesWithCantInstantiateException() {
     final String package1 = BASE_PACKAGE + ".wrong1";
     final String package2 = BASE_PACKAGE + ".wrong2";
     final ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
@@ -329,7 +330,7 @@ public class PackageObjectFactoryTest {
   }
 
   @Test
-  public void testCreateObjectFromFullModuleNamesWithExceptionByBruteForce() {
+  void createObjectFromFullModuleNamesWithExceptionByBruteForce() {
     final String package1 = BASE_PACKAGE + ".wrong1";
     final String package2 = BASE_PACKAGE + ".wrong2";
     final ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
@@ -378,7 +379,7 @@ public class PackageObjectFactoryTest {
   }
 
   @Test
-  public void testCreateObjectByBruteForce() throws Exception {
+  void createObjectByBruteForce() throws Exception {
     final String className = "Checker";
     final Method createModuleByBruteForce =
         PackageObjectFactory.class.getDeclaredMethod(
@@ -391,7 +392,7 @@ public class PackageObjectFactoryTest {
   }
 
   @Test
-  public void testCreateCheckByBruteForce() throws Exception {
+  void createCheckByBruteForce() throws Exception {
     final String checkName = "AnnotationLocation";
     final Method createModuleByBruteForce =
         PackageObjectFactory.class.getDeclaredMethod(
@@ -410,11 +411,11 @@ public class PackageObjectFactoryTest {
   }
 
   @Test
-  public void testCreateCheckWithPartialPackageNameByBruteForce() throws Exception {
+  void createCheckWithPartialPackageNameByBruteForce() throws Exception {
     final String checkName = "checks.annotation.AnnotationLocation";
     final PackageObjectFactory packageObjectFactory =
         new PackageObjectFactory(
-            new HashSet<>(Collections.singletonList(BASE_PACKAGE)),
+            new HashSet<>(ImmutableList.of(BASE_PACKAGE)),
             Thread.currentThread().getContextClassLoader(),
             TRY_IN_ALL_REGISTERED_PACKAGES);
     final AnnotationLocationCheck check =
@@ -425,21 +426,21 @@ public class PackageObjectFactoryTest {
   }
 
   @Test
-  public void testJoinPackageNamesWithClassName() throws Exception {
+  void joinPackageNamesWithClassName() throws Exception {
     final Class<PackageObjectFactory> clazz = PackageObjectFactory.class;
     final Method method =
         clazz.getDeclaredMethod("joinPackageNamesWithClassName", String.class, Set.class);
     method.setAccessible(true);
-    final Set<String> packages = Collections.singleton("test");
+    final Set<String> packages = ImmutableSet.of("test");
     final String className = "SomeClass";
     final String actual =
         String.valueOf(method.invoke(PackageObjectFactory.class, className, packages));
     assertWithMessage("Invalid class name").that(actual).isEqualTo("test." + className);
   }
 
-  @Test
   @SuppressWarnings("unchecked")
-  public void testNameToFullModuleNameMap() throws Exception {
+  @Test
+  void nameToFullModuleNameMap() throws Exception {
     final Set<Class<?>> classes = CheckUtil.getCheckstyleModules();
     final Class<PackageObjectFactory> packageObjectFactoryClass = PackageObjectFactory.class;
     final Field field = packageObjectFactoryClass.getDeclaredField("NAME_TO_FULL_MODULE_NAME");
@@ -470,7 +471,7 @@ public class PackageObjectFactoryTest {
   }
 
   @Test
-  public void testConstructorFailure() {
+  void constructorFailure() {
     try {
       factory.createModule(FailConstructorFileSet.class.getName());
       assertWithMessage("Exception is expected").fail();
@@ -487,7 +488,7 @@ public class PackageObjectFactoryTest {
   }
 
   @Test
-  public void testGetShortFromFullModuleNames() {
+  void getShortFromFullModuleNames() {
     final String fullName = "com.puppycrawl.tools.checkstyle.checks.coding.DefaultComesLastCheck";
 
     assertWithMessage("Invalid simple check name")
@@ -496,7 +497,7 @@ public class PackageObjectFactoryTest {
   }
 
   @Test
-  public void testGetShortFromFullModuleNamesThirdParty() {
+  void getShortFromFullModuleNamesThirdParty() {
     final String fullName = "java.util.stream.Collectors";
 
     assertWithMessage("Invalid simple check name")
@@ -516,11 +517,11 @@ public class PackageObjectFactoryTest {
    * @throws Exception when the code tested throws an exception
    */
   @Test
-  public void testGenerateThirdPartyNameToFullModuleNameWithException() throws Exception {
+  void generateThirdPartyNameToFullModuleNameWithException() throws Exception {
     final String name = "String";
     final String packageName = "java.lang";
     final ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
-    final Set<String> packages = Collections.singleton(packageName);
+    final Set<String> packages = ImmutableSet.of(packageName);
     final PackageObjectFactory objectFactory =
         new PackageObjectFactory(packages, classLoader, TRY_IN_ALL_REGISTERED_PACKAGES);
 
@@ -544,9 +545,9 @@ public class PackageObjectFactoryTest {
   }
 
   @Test
-  public void testCreateObjectWithNameContainingPackageSeparator() throws Exception {
+  void createObjectWithNameContainingPackageSeparator() throws Exception {
     final ClassLoader classLoader = ClassLoader.getSystemClassLoader();
-    final Set<String> packages = Collections.singleton(BASE_PACKAGE);
+    final Set<String> packages = ImmutableSet.of(BASE_PACKAGE);
     final PackageObjectFactory objectFactory =
         new PackageObjectFactory(packages, classLoader, TRY_IN_ALL_REGISTERED_PACKAGES);
 
@@ -562,9 +563,9 @@ public class PackageObjectFactoryTest {
    * It ensures that ModuleReflectionUtil.getCheckstyleModules is not executed in this case.
    */
   @Test
-  public void testCreateObjectWithNameContainingPackageSeparatorWithoutSearch() throws Exception {
+  void createObjectWithNameContainingPackageSeparatorWithoutSearch() throws Exception {
     final ClassLoader classLoader = ClassLoader.getSystemClassLoader();
-    final Set<String> packages = Collections.singleton(BASE_PACKAGE);
+    final Set<String> packages = ImmutableSet.of(BASE_PACKAGE);
     final PackageObjectFactory objectFactory =
         new PackageObjectFactory(packages, classLoader, TRY_IN_ALL_REGISTERED_PACKAGES);
 
@@ -588,9 +589,9 @@ public class PackageObjectFactoryTest {
   }
 
   @Test
-  public void testCreateModuleWithTryInAllRegisteredPackages() {
+  void createModuleWithTryInAllRegisteredPackages() {
     final ClassLoader classLoader = ClassLoader.getSystemClassLoader();
-    final Set<String> packages = Collections.singleton(BASE_PACKAGE);
+    final Set<String> packages = ImmutableSet.of(BASE_PACKAGE);
     final PackageObjectFactory objectFactory =
         new PackageObjectFactory(packages, classLoader, SEARCH_REGISTERED_PACKAGES);
     final CheckstyleException ex =
@@ -611,7 +612,7 @@ public class PackageObjectFactoryTest {
   }
 
   @Test
-  public void testExceptionMessage() {
+  void exceptionMessage() {
     final String barPackage = BASE_PACKAGE + ".packageobjectfactory.bar";
     final String fooPackage = BASE_PACKAGE + ".packageobjectfactory.foo";
     final String zooPackage = BASE_PACKAGE + ".packageobjectfactory.zoo";
--- a/src/test/java/com/puppycrawl/tools/checkstyle/PropertiesExpanderTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/PropertiesExpanderTest.java
@@ -24,10 +24,10 @@ import static com.google.common.truth.Truth.assertWithMessage;
 import java.util.Properties;
 import org.junit.jupiter.api.Test;
 
-public class PropertiesExpanderTest {
+final class PropertiesExpanderTest {
 
   @Test
-  public void testCtorException() {
+  void ctorException() {
     try {
       final Object test = new PropertiesExpander(null);
       assertWithMessage("exception expected but got " + test).fail();
@@ -39,7 +39,7 @@ public class PropertiesExpanderTest {
   }
 
   @Test
-  public void testDefaultProperties() {
+  void defaultProperties() {
     final Properties properties = new Properties(System.getProperties());
     properties.setProperty("test", "checkstyle");
     final String propertiesUserHome = properties.getProperty("user.home");
--- a/src/test/java/com/puppycrawl/tools/checkstyle/PropertyCacheFileTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/PropertyCacheFileTest.java
@@ -54,7 +54,7 @@ import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ValueSource;
 import org.mockito.MockedStatic;
 
-public class PropertyCacheFileTest extends AbstractPathTestSupport {
+final class PropertyCacheFileTest extends AbstractPathTestSupport {
 
   @TempDir public File temporaryFolder;
 
@@ -64,7 +64,7 @@ public class PropertyCacheFileTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testCtor() {
+  void ctor() {
     try {
       final Object test = new PropertyCacheFile(null, "");
       assertWithMessage("exception expected but got " + test).fail();
@@ -85,7 +85,7 @@ public class PropertyCacheFileTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testInCache() throws IOException {
+  void inCache() throws IOException {
     final Configuration config = new DefaultConfiguration("myName");
     final String filePath = File.createTempFile("junit", null, temporaryFolder).getPath();
     final PropertyCacheFile cache = new PropertyCacheFile(config, filePath);
@@ -102,7 +102,7 @@ public class PropertyCacheFileTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testResetIfFileDoesNotExist() throws IOException {
+  void resetIfFileDoesNotExist() throws IOException {
     final Configuration config = new DefaultConfiguration("myName");
     final PropertyCacheFile cache = new PropertyCacheFile(config, "fileDoesNotExist.txt");
 
@@ -114,7 +114,7 @@ public class PropertyCacheFileTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testPopulateDetails() throws IOException {
+  void populateDetails() throws IOException {
     final Configuration config = new DefaultConfiguration("myName");
     final PropertyCacheFile cache =
         new PropertyCacheFile(config, getPath("InputPropertyCacheFile"));
@@ -136,7 +136,7 @@ public class PropertyCacheFileTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testConfigHashOnReset() throws IOException {
+  void configHashOnReset() throws IOException {
     final Configuration config = new DefaultConfiguration("myName");
     final String filePath = File.createTempFile("junit", null, temporaryFolder).getPath();
     final PropertyCacheFile cache = new PropertyCacheFile(config, filePath);
@@ -154,7 +154,7 @@ public class PropertyCacheFileTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testConfigHashRemainsOnResetExternalResources() throws IOException {
+  void configHashRemainsOnResetExternalResources() throws IOException {
     final Configuration config = new DefaultConfiguration("myName");
     final String filePath = File.createTempFile("junit", null, temporaryFolder).getPath();
     final PropertyCacheFile cache = new PropertyCacheFile(config, filePath);
@@ -180,7 +180,7 @@ public class PropertyCacheFileTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testCacheRemainsWhenExternalResourceTheSame() throws IOException {
+  void cacheRemainsWhenExternalResourceTheSame() throws IOException {
     final Configuration config = new DefaultConfiguration("myName");
     final String externalResourcePath =
         File.createTempFile("junit", null, temporaryFolder).getPath();
@@ -209,7 +209,7 @@ public class PropertyCacheFileTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testExternalResourceIsSavedInCache() throws Exception {
+  void externalResourceIsSavedInCache() throws Exception {
     final Configuration config = new DefaultConfiguration("myName");
     final String filePath = File.createTempFile("junit", null, temporaryFolder).getPath();
     final PropertyCacheFile cache = new PropertyCacheFile(config, filePath);
@@ -223,7 +223,7 @@ public class PropertyCacheFileTest extends AbstractPathTestSupport {
 
     final MessageDigest digest = MessageDigest.getInstance("SHA-1");
     final URI uri = CommonUtil.getUriByFilename(pathToResource);
-    final byte[] input = ByteStreams.toByteArray(new BufferedInputStream(uri.toURL().openStream()));
+    final byte[] input = new BufferedInputStream(uri.toURL().openStream()).readAllBytes();
     final ByteArrayOutputStream out = new ByteArrayOutputStream();
     try (ObjectOutputStream oos = new ObjectOutputStream(out)) {
       oos.writeObject(input);
@@ -237,7 +237,7 @@ public class PropertyCacheFileTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testCacheDirectoryDoesNotExistAndShouldBeCreated() throws IOException {
+  void cacheDirectoryDoesNotExistAndShouldBeCreated() throws IOException {
     final Configuration config = new DefaultConfiguration("myName");
     final String filePath =
         String.format(Locale.ENGLISH, "%s%2$stemp%2$scache.temp", temporaryFolder, File.separator);
@@ -250,7 +250,7 @@ public class PropertyCacheFileTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testPathToCacheContainsOnlyFileName() throws IOException {
+  void pathToCacheContainsOnlyFileName() throws IOException {
     final Configuration config = new DefaultConfiguration("myName");
     final String fileName = "temp.cache";
     final Path filePath = Paths.get(fileName);
@@ -263,9 +263,9 @@ public class PropertyCacheFileTest extends AbstractPathTestSupport {
     Files.delete(filePath);
   }
 
-  @Test
   @DisabledOnOs(OS.WINDOWS)
-  public void testPersistWithSymbolicLinkToDirectory() throws IOException {
+  @Test
+  void persistWithSymbolicLinkToDirectory() throws IOException {
     final Path tempDirectory = Files.createTempDirectory("tempDir");
     final Path symbolicLinkDirectory =
         Files.createTempDirectory("symbolicLinkDir").resolve("symbolicLink");
@@ -283,9 +283,9 @@ public class PropertyCacheFileTest extends AbstractPathTestSupport {
         .isTrue();
   }
 
-  @Test
   @DisabledOnOs(OS.WINDOWS)
-  public void testSymbolicLinkResolution() throws IOException {
+  @Test
+  void symbolicLinkResolution() throws IOException {
     final Path tempDirectory = Files.createTempDirectory("tempDir");
     final Path symbolicLinkDirectory =
         Files.createTempDirectory("symbolicLinkDir").resolve("symbolicLink");
@@ -303,9 +303,9 @@ public class PropertyCacheFileTest extends AbstractPathTestSupport {
         .isTrue();
   }
 
-  @Test
   @DisabledOnOs(OS.WINDOWS)
-  public void testSymbolicLinkToNonDirectory() throws IOException {
+  @Test
+  void symbolicLinkToNonDirectory() throws IOException {
     final Path tempFile = Files.createTempFile("tempFile", null);
     final Path symbolicLinkDirectory = Files.createTempDirectory("symbolicLinkDir");
     final Path symbolicLink = symbolicLinkDirectory.resolve("symbolicLink");
@@ -325,9 +325,9 @@ public class PropertyCacheFileTest extends AbstractPathTestSupport {
         .contains(expectedMessage);
   }
 
-  @Test
   @DisabledOnOs(OS.WINDOWS)
-  public void testMultipleSymbolicLinkResolution() throws IOException {
+  @Test
+  void multipleSymbolicLinkResolution() throws IOException {
     final Path actualDirectory = Files.createTempDirectory("actualDir");
     final Path firstSymbolicLink = Files.createTempDirectory("firstLinkDir").resolve("firstLink");
     Files.createSymbolicLink(firstSymbolicLink, actualDirectory);
@@ -349,7 +349,7 @@ public class PropertyCacheFileTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testChangeInConfig() throws Exception {
+  void changeInConfig() throws Exception {
     final DefaultConfiguration config = new DefaultConfiguration("myConfig");
     config.addProperty("attr", "value");
 
@@ -401,11 +401,11 @@ public class PropertyCacheFileTest extends AbstractPathTestSupport {
    * @noinspectionreason ResultOfMethodCallIgnored - Setup for mockito to only mock toByteArray to
    *     throw exception.
    */
-  @Test
+  @SuppressWarnings("InputStreamReadAllBytes")
   // XXX: Drop suppression once
   // https://github.com/checkstyle/checkstyle/pull/14362 is resolved.
-  @SuppressWarnings("InputStreamReadAllBytes")
-  public void testNonExistentResource() throws IOException {
+  @Test
+  void nonExistentResource() throws IOException {
     final Configuration config = new DefaultConfiguration("myName");
     final String filePath = File.createTempFile("junit", null, temporaryFolder).getPath();
     final PropertyCacheFile cache = new PropertyCacheFile(config, filePath);
@@ -440,7 +440,7 @@ public class PropertyCacheFileTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testExceptionNoSuchAlgorithmException() throws Exception {
+  void exceptionNoSuchAlgorithmException() throws Exception {
     final Configuration config = new DefaultConfiguration("myName");
     final String filePath = File.createTempFile("junit", null, temporaryFolder).getPath();
     final PropertyCacheFile cache = new PropertyCacheFile(config, filePath);
@@ -479,8 +479,8 @@ public class PropertyCacheFileTest extends AbstractPathTestSupport {
    * @param rawMessages exception messages separated by ';'
    */
   @ParameterizedTest
-  @ValueSource(strings = {"Same;Same", "First;Second"})
-  public void testPutNonExistentExternalResource(String rawMessages) throws Exception {
+  @ValueSource(strings = {"First;Second", "Same;Same"})
+  void putNonExistentExternalResource(String rawMessages) throws Exception {
     final File cacheFile = File.createTempFile("junit", null, temporaryFolder);
     final String[] messages = rawMessages.split(";");
     // We mock getUriByFilename method of CommonUtil to guarantee that it will
--- a/src/test/java/com/puppycrawl/tools/checkstyle/SarifLoggerTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/SarifLoggerTest.java
@@ -20,6 +20,7 @@
 package com.puppycrawl.tools.checkstyle;
 
 import static com.google.common.truth.Truth.assertWithMessage;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.puppycrawl.tools.checkstyle.AbstractAutomaticBean.OutputStreamOptions;
 import com.puppycrawl.tools.checkstyle.api.AuditEvent;
@@ -29,10 +30,9 @@ import com.puppycrawl.tools.checkstyle.internal.utils.CloseAndFlushTestByteArray
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.PrintWriter;
-import java.nio.charset.StandardCharsets;
 import org.junit.jupiter.api.Test;
 
-public class SarifLoggerTest extends AbstractModuleTestSupport {
+final class SarifLoggerTest extends AbstractModuleTestSupport {
 
   /**
    * Output stream to hold the test results. The IntelliJ IDEA issues the AutoCloseableResource
@@ -48,7 +48,7 @@ public class SarifLoggerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEscape() {
+  void escape() {
     final String[][] encodings = {
       {"\"", "\\\""},
       {"\\", "\\\\"},
@@ -71,7 +71,7 @@ public class SarifLoggerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAddError() throws IOException {
+  void addError() throws IOException {
     final SarifLogger logger = new SarifLogger(outStream, OutputStreamOptions.CLOSE);
     logger.auditStarted(null);
     final Violation violation =
@@ -94,7 +94,7 @@ public class SarifLoggerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAddErrorWithWarningLevel() throws IOException {
+  void addErrorWithWarningLevel() throws IOException {
     final SarifLogger logger = new SarifLogger(outStream, OutputStreamOptions.CLOSE);
     logger.auditStarted(null);
     final Violation violation =
@@ -117,7 +117,7 @@ public class SarifLoggerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAddErrors() throws IOException {
+  void addErrors() throws IOException {
     final SarifLogger logger = new SarifLogger(outStream, OutputStreamOptions.CLOSE);
     logger.auditStarted(null);
     final Violation violation =
@@ -155,7 +155,7 @@ public class SarifLoggerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAddException() throws IOException {
+  void addException() throws IOException {
     final SarifLogger logger = new SarifLogger(outStream, OutputStreamOptions.CLOSE);
     logger.auditStarted(null);
     final Violation message =
@@ -170,7 +170,7 @@ public class SarifLoggerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAddExceptions() throws IOException {
+  void addExceptions() throws IOException {
     final SarifLogger logger = new SarifLogger(outStream, OutputStreamOptions.CLOSE);
     logger.auditStarted(null);
     final Violation violation =
@@ -192,7 +192,7 @@ public class SarifLoggerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLineOnly() throws IOException {
+  void lineOnly() throws IOException {
     final SarifLogger logger = new SarifLogger(outStream, OutputStreamOptions.CLOSE);
     logger.auditStarted(null);
     final Violation violation =
@@ -207,7 +207,7 @@ public class SarifLoggerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmpty() throws IOException {
+  void empty() throws IOException {
     final SarifLogger logger = new SarifLogger(outStream, OutputStreamOptions.CLOSE);
     logger.auditStarted(null);
     final Violation violation =
@@ -221,7 +221,7 @@ public class SarifLoggerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNullOutputStreamOptions() {
+  void nullOutputStreamOptions() {
     try {
       final SarifLogger logger = new SarifLogger(outStream, null);
       // assert required to calm down eclipse's 'The allocated object is never used' violation
@@ -235,7 +235,7 @@ public class SarifLoggerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCloseStream() throws IOException {
+  void closeStream() throws IOException {
     final SarifLogger logger = new SarifLogger(outStream, OutputStreamOptions.CLOSE);
     logger.auditStarted(null);
     logger.auditFinished(null);
@@ -246,7 +246,7 @@ public class SarifLoggerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoCloseStream() throws IOException {
+  void noCloseStream() throws IOException {
     final SarifLogger logger = new SarifLogger(outStream, OutputStreamOptions.NONE);
     logger.auditStarted(null);
     logger.auditFinished(null);
@@ -259,7 +259,7 @@ public class SarifLoggerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFinishLocalSetup() throws IOException {
+  void finishLocalSetup() throws IOException {
     final SarifLogger logger = new SarifLogger(outStream, OutputStreamOptions.CLOSE);
     logger.finishLocalSetup();
     logger.auditStarted(null);
@@ -268,7 +268,7 @@ public class SarifLoggerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testReadResourceWithInvalidName() {
+  void readResourceWithInvalidName() {
     try {
       SarifLogger.readResource("random");
       assertWithMessage("Exception expected").fail();
@@ -282,8 +282,7 @@ public class SarifLoggerTest extends AbstractModuleTestSupport {
   private static void verifyContent(
       String expectedOutputFile, ByteArrayOutputStream actualOutputStream) throws IOException {
     final String expectedContent = readFile(expectedOutputFile);
-    final String actualContent =
-        toLfLineEnding(actualOutputStream.toString(StandardCharsets.UTF_8));
+    final String actualContent = toLfLineEnding(actualOutputStream.toString(UTF_8));
     assertWithMessage("sarif content should match").that(actualContent).isEqualTo(expectedContent);
   }
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/SuppressionsStringPrinterTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/SuppressionsStringPrinterTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
 import java.io.File;
 import org.junit.jupiter.api.Test;
 
-public class SuppressionsStringPrinterTest extends AbstractTreeTestSupport {
+final class SuppressionsStringPrinterTest extends AbstractTreeTestSupport {
 
   private static final String EOL = System.getProperty("line.separator");
 
@@ -36,14 +36,14 @@ public class SuppressionsStringPrinterTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testIsProperUtilsClass() throws ReflectiveOperationException {
+  void isProperUtilsClass() throws ReflectiveOperationException {
     assertWithMessage("Constructor is not private")
         .that(isUtilsClassHasPrivateConstructor(SuppressionsStringPrinter.class))
         .isTrue();
   }
 
   @Test
-  public void testCorrect() throws Exception {
+  void correct() throws Exception {
     final String expected =
         "/COMPILATION_UNIT/CLASS_DEF"
             + "[./IDENT[@text='InputSuppressionsStringPrinter']]"
@@ -65,7 +65,7 @@ public class SuppressionsStringPrinterTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testCustomTabWidth() throws Exception {
+  void customTabWidth() throws Exception {
     final String expected =
         "/COMPILATION_UNIT/CLASS_DEF"
             + "[./IDENT[@text='InputSuppressionsStringPrinter']]"
@@ -90,7 +90,7 @@ public class SuppressionsStringPrinterTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testCustomTabWidthEmptyResult() throws Exception {
+  void customTabWidthEmptyResult() throws Exception {
     final File input = new File(getPath("InputSuppressionsStringPrinter.java"));
     final String lineAndColumnNumber = "5:13";
     final int tabWidth = 6;
@@ -100,7 +100,7 @@ public class SuppressionsStringPrinterTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testInvalidLineAndColumnNumberParameter() throws Exception {
+  void invalidLineAndColumnNumberParameter() throws Exception {
     final File input = new File(getPath("InputSuppressionsStringPrinter.java"));
     final String invalidLineAndColumnNumber = "abc-432";
     final int tabWidth = 2;
@@ -115,7 +115,7 @@ public class SuppressionsStringPrinterTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testParseFileTextThrowable() throws Exception {
+  void parseFileTextThrowable() throws Exception {
     final File input = new File(getNonCompilablePath("InputSuppressionsStringPrinter.java"));
     final String lineAndColumnNumber = "2:3";
     final int tabWidth = 2;
--- a/src/test/java/com/puppycrawl/tools/checkstyle/ThreadModeSettingsTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/ThreadModeSettingsTest.java
@@ -25,10 +25,10 @@ import com.puppycrawl.tools.checkstyle.internal.utils.CheckUtil;
 import java.util.Set;
 import org.junit.jupiter.api.Test;
 
-public class ThreadModeSettingsTest {
+final class ThreadModeSettingsTest {
 
   @Test
-  public void testProperties() {
+  void properties() {
     final ThreadModeSettings config = new ThreadModeSettings(1, 2);
     assertWithMessage("Invalid checker threads number")
         .that(config.getCheckerThreadsNumber())
@@ -39,7 +39,7 @@ public class ThreadModeSettingsTest {
   }
 
   @Test
-  public void testResolveCheckerInMultiThreadMode() {
+  void resolveCheckerInMultiThreadMode() {
     final ThreadModeSettings configuration = new ThreadModeSettings(2, 2);
 
     try {
@@ -53,7 +53,7 @@ public class ThreadModeSettingsTest {
   }
 
   @Test
-  public void testResolveCheckerInSingleThreadMode() {
+  void resolveCheckerInSingleThreadMode() {
     final ThreadModeSettings singleThreadMode = ThreadModeSettings.SINGLE_THREAD_MODE_INSTANCE;
 
     final String name = singleThreadMode.resolveName(ThreadModeSettings.CHECKER_MODULE_NAME);
@@ -63,7 +63,7 @@ public class ThreadModeSettingsTest {
   }
 
   @Test
-  public void testResolveTreeWalker() {
+  void resolveTreeWalker() {
     final ThreadModeSettings configuration = new ThreadModeSettings(2, 2);
 
     try {
@@ -77,7 +77,7 @@ public class ThreadModeSettingsTest {
   }
 
   @Test
-  public void testResolveTreeWalkerInSingleThreadMode() {
+  void resolveTreeWalkerInSingleThreadMode() {
     final ThreadModeSettings singleThreadMode = ThreadModeSettings.SINGLE_THREAD_MODE_INSTANCE;
     final String actual = singleThreadMode.resolveName(ThreadModeSettings.TREE_WALKER_MODULE_NAME);
     assertWithMessage("Invalid name resolved: " + actual)
@@ -86,7 +86,7 @@ public class ThreadModeSettingsTest {
   }
 
   @Test
-  public void testResolveAnyOtherModule() throws Exception {
+  void resolveAnyOtherModule() throws Exception {
     final Set<Class<?>> allModules = CheckUtil.getCheckstyleModules();
     final ThreadModeSettings multiThreadModeSettings = new ThreadModeSettings(2, 2);
     final ThreadModeSettings singleThreadModeSettings =
--- a/src/test/java/com/puppycrawl/tools/checkstyle/TreeWalkerTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/TreeWalkerTest.java
@@ -21,11 +21,15 @@ package com.puppycrawl.tools.checkstyle;
 
 import static com.google.common.truth.Truth.assertWithMessage;
 import static com.puppycrawl.tools.checkstyle.checks.naming.AbstractNameCheck.MSG_INVALID_PATTERN;
+import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.CALLS_REAL_METHODS;
 import static org.mockito.Mockito.doThrow;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.mockConstruction;
+import static org.mockito.Mockito.mockStatic;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
 import com.puppycrawl.tools.checkstyle.api.Configuration;
@@ -59,7 +63,6 @@ import java.nio.file.Files;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
@@ -91,10 +94,10 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testProperFileExtension() throws Exception {
+  void properFileExtension() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(ConstantNameCheck.class);
     final File file = new File(temporaryFolder, "file.java");
-    try (Writer writer = Files.newBufferedWriter(file.toPath(), StandardCharsets.UTF_8)) {
+    try (Writer writer = Files.newBufferedWriter(file.toPath(), UTF_8)) {
       final String content = "public class Main { public static final int k = 5 + 4; }";
       writer.write(content);
     }
@@ -132,7 +135,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
    * @throws Exception if an error occurs
    */
   @Test
-  public void testNoAuditEventsWithoutFilters() throws Exception {
+  void noAuditEventsWithoutFilters() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(OneTopLevelClassCheck.class);
     final String[] expected = {
       "5:1: "
@@ -140,7 +143,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
               OneTopLevelClassCheck.class, OneTopLevelClassCheck.MSG_KEY, "InputTreeWalkerInner"),
     };
     try (MockedConstruction<TreeWalkerAuditEvent> mocked =
-        Mockito.mockConstruction(
+        mockConstruction(
             TreeWalkerAuditEvent.class,
             (mock, context) -> {
               throw new CheckstyleException("No audit events expected");
@@ -154,7 +157,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
    * that the {@code if (!ordinaryChecks.isEmpty())} condition cannot be removed.
    */
   @Test
-  public void testConditionRequiredWithoutOrdinaryChecks() throws Exception {
+  void conditionRequiredWithoutOrdinaryChecks() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(JavadocParagraphCheck.class);
     final String[] expected = {
       "3: "
@@ -167,7 +170,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
         JavaParser.parseFile(new File(path), JavaParser.Options.WITH_COMMENTS);
     // Ensure that there is no calls to walk(..., AstState.ORDINARY)
     doThrow(IllegalStateException.class).when(mockAst).getFirstChild();
-    try (MockedStatic<JavaParser> parser = Mockito.mockStatic(JavaParser.class)) {
+    try (MockedStatic<JavaParser> parser = mockStatic(JavaParser.class)) {
       parser.when(() -> JavaParser.parse(any(FileContents.class))).thenReturn(mockAst);
       // This will re-enable walk(..., AstState.WITH_COMMENTS)
       parser.when(() -> JavaParser.appendHiddenCommentNodes(mockAst)).thenReturn(realAst);
@@ -181,15 +184,14 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
    * that the {@code if (!commentChecks.isEmpty())} condition cannot be removed.
    */
   @Test
-  public void testConditionRequiredWithoutCommentChecks() throws Exception {
+  void conditionRequiredWithoutCommentChecks() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(OneTopLevelClassCheck.class);
     final String[] expected = {
       "5:1: "
           + getCheckMessage(
               OneTopLevelClassCheck.class, OneTopLevelClassCheck.MSG_KEY, "InputTreeWalkerInner"),
     };
-    try (MockedStatic<JavaParser> parser =
-        Mockito.mockStatic(JavaParser.class, CALLS_REAL_METHODS)) {
+    try (MockedStatic<JavaParser> parser = mockStatic(JavaParser.class, CALLS_REAL_METHODS)) {
       // Ensure that there is no calls to walk(..., AstState.WITH_COMMENTS)
       parser
           .when(() -> JavaParser.appendHiddenCommentNodes(any(DetailAST.class)))
@@ -200,10 +202,10 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testImproperFileExtension() throws Exception {
+  void improperFileExtension() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(ConstantNameCheck.class);
     final File file = new File(temporaryFolder, "file.pdf");
-    try (Writer writer = Files.newBufferedWriter(file.toPath(), StandardCharsets.UTF_8)) {
+    try (Writer writer = Files.newBufferedWriter(file.toPath(), UTF_8)) {
       final String content = "public class Main { public static final int k = 5 + 4; }";
       writer.write(content);
     }
@@ -212,7 +214,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAcceptableTokens() throws Exception {
+  void acceptableTokens() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(HiddenFieldCheck.class);
     checkConfig.addProperty("tokens", "VARIABLE_DEF, ENUM_DEF, CLASS_DEF, METHOD_DEF," + "IMPORT");
     try {
@@ -237,7 +239,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOnEmptyFile() throws Exception {
+  void onEmptyFile() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(HiddenFieldCheck.class);
     final String pathToEmptyFile = File.createTempFile("file", ".java", temporaryFolder).getPath();
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -246,7 +248,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithCheckNotHavingTreeWalkerAsParent() throws Exception {
+  void withCheckNotHavingTreeWalkerAsParent() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(JavadocPackageCheck.class);
 
     try {
@@ -264,7 +266,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSetupChildExceptions() {
+  void setupChildExceptions() {
     final TreeWalker treeWalker = new TreeWalker();
     final PackageObjectFactory factory =
         new PackageObjectFactory(new HashSet<>(), Thread.currentThread().getContextClassLoader());
@@ -285,7 +287,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSettersForParameters() throws Exception {
+  void settersForParameters() throws Exception {
     final TreeWalker treeWalker = new TreeWalker();
     final DefaultConfiguration config = new DefaultConfiguration("default config");
     treeWalker.setTabWidth(1);
@@ -298,7 +300,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testForInvalidCheckImplementation() throws Exception {
+  void forInvalidCheckImplementation() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(BadJavaDocCheck.class);
     final String pathToEmptyFile = File.createTempFile("file", ".java", temporaryFolder).getPath();
 
@@ -322,7 +324,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testProcessNonJavaFiles() throws Exception {
+  void processNonJavaFiles() throws Exception {
     final TreeWalker treeWalker = new TreeWalker();
     final PackageObjectFactory factory =
         new PackageObjectFactory(new HashSet<>(), Thread.currentThread().getContextClassLoader());
@@ -350,7 +352,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testProcessNonJavaFilesWithoutException() throws Exception {
+  void processNonJavaFilesWithoutException() throws Exception {
     final TreeWalker treeWalker = new TreeWalker();
     treeWalker.setTabWidth(1);
     treeWalker.configure(new DefaultConfiguration("default config"));
@@ -362,7 +364,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithCacheWithNoViolation() throws Exception {
+  void withCacheWithNoViolation() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(HiddenFieldCheck.class);
     final Checker checker = createChecker(checkConfig);
     final PackageObjectFactory factory =
@@ -375,7 +377,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testProcessWithParserThrowable() throws Exception {
+  void processWithParserThrowable() throws Exception {
     final TreeWalker treeWalker = new TreeWalker();
     treeWalker.configure(createModuleConfig(TypeNameCheck.class));
     final PackageObjectFactory factory =
@@ -398,7 +400,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testProcessWithRecognitionException() throws Exception {
+  void processWithRecognitionException() throws Exception {
     final TreeWalker treeWalker = new TreeWalker();
     treeWalker.configure(createModuleConfig(TypeNameCheck.class));
     final PackageObjectFactory factory =
@@ -421,7 +423,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRequiredTokenIsEmptyIntArray() throws Exception {
+  void requiredTokenIsEmptyIntArray() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RequiredTokenIsEmptyIntArray.class);
     final String pathToEmptyFile = File.createTempFile("file", ".java", temporaryFolder).getPath();
 
@@ -430,7 +432,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBehaviourWithZeroChecks() throws Exception {
+  void behaviourWithZeroChecks() throws Exception {
     final TreeWalker treeWalker = new TreeWalker();
     final PackageObjectFactory factory =
         new PackageObjectFactory(new HashSet<>(), Thread.currentThread().getContextClassLoader());
@@ -445,7 +447,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBehaviourWithOrdinaryAndCommentChecks() throws Exception {
+  void behaviourWithOrdinaryAndCommentChecks() throws Exception {
     final TreeWalker treeWalker = new TreeWalker();
     treeWalker.configure(createModuleConfig(TypeNameCheck.class));
     treeWalker.configure(createModuleConfig(CommentsIndentationCheck.class));
@@ -472,7 +474,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSetupChild() throws Exception {
+  void setupChild() throws Exception {
     final TreeWalker treeWalker = new TreeWalker();
     final PackageObjectFactory factory =
         new PackageObjectFactory(new HashSet<>(), Thread.currentThread().getContextClassLoader());
@@ -492,7 +494,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBehaviourWithChecksAndFilters() throws Exception {
+  void behaviourWithChecksAndFilters() throws Exception {
     final DefaultConfiguration filterConfig = createModuleConfig(SuppressionCommentFilter.class);
     filterConfig.addProperty("checkCPP", "false");
 
@@ -513,7 +515,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMultiCheckOrder() throws Exception {
+  void multiCheckOrder() throws Exception {
     final DefaultConfiguration treeWalkerConfig = createModuleConfig(TreeWalker.class);
     treeWalkerConfig.addChild(createModuleConfig(WhitespaceAroundCheck.class));
     treeWalkerConfig.addChild(createModuleConfig(WhitespaceAfterCheck.class));
@@ -527,7 +529,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMultiCheckOfSameTypeNoIdResultsInOrderingByHash() throws Exception {
+  void multiCheckOfSameTypeNoIdResultsInOrderingByHash() throws Exception {
 
     final DefaultConfiguration configuration1 = createModuleConfig(ParameterNameCheck.class);
     configuration1.addProperty("format", "^[a-z]([a-z0-9][a-zA-Z0-9]*)?$");
@@ -557,7 +559,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFinishLocalSetupFullyInitialized() {
+  void finishLocalSetupFullyInitialized() {
     final TreeWalker treeWalker = new TreeWalker();
     treeWalker.setSeverity("error");
     treeWalker.setTabWidth(100);
@@ -573,7 +575,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCheckInitIsCalledInTreeWalker() throws Exception {
+  void checkInitIsCalledInTreeWalker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(VerifyInitCheck.class);
     final File file = File.createTempFile("file", ".pdf", temporaryFolder);
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -582,7 +584,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCheckDestroyIsCalledInTreeWalker() throws Exception {
+  void checkDestroyIsCalledInTreeWalker() throws Exception {
     VerifyDestroyCheck.resetDestroyWasCalled();
     final DefaultConfiguration checkConfig = createModuleConfig(VerifyDestroyCheck.class);
     final File file = File.createTempFile("file", ".pdf", temporaryFolder);
@@ -594,7 +596,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommentCheckDestroyIsCalledInTreeWalker() throws Exception {
+  void commentCheckDestroyIsCalledInTreeWalker() throws Exception {
     VerifyDestroyCheck.resetDestroyWasCalled();
     final DefaultConfiguration checkConfig = createModuleConfig(VerifyDestroyCommentCheck.class);
     final File file = File.createTempFile("file", ".pdf", temporaryFolder);
@@ -606,7 +608,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCacheWhenFileExternalResourceContentDoesNotChange() throws Exception {
+  void cacheWhenFileExternalResourceContentDoesNotChange() throws Exception {
     final DefaultConfiguration filterConfig = createModuleConfig(SuppressionXpathFilter.class);
     filterConfig.addProperty("file", getPath("InputTreeWalkerSuppressionXpathFilter.xml"));
     final DefaultConfiguration treeWalkerConfig = createModuleConfig(TreeWalker.class);
@@ -629,7 +631,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTreeWalkerFilterAbsolutePath() throws Exception {
+  void treeWalkerFilterAbsolutePath() throws Exception {
     final DefaultConfiguration filterConfig = createModuleConfig(SuppressionXpathFilter.class);
     filterConfig.addProperty("file", getPath("InputTreeWalkerSuppressionXpathFilterAbsolute.xml"));
     final DefaultConfiguration checkConfig = createModuleConfig(LeftCurlyCheck.class);
@@ -649,7 +651,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExternalResourceFiltersWithNoExternalResource() throws Exception {
+  void externalResourceFiltersWithNoExternalResource() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(EmptyStatementCheck.class);
     final DefaultConfiguration filterConfig =
         createModuleConfig(SuppressWithNearbyCommentFilter.class);
@@ -673,7 +675,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
    * @throws Exception if file is not found
    */
   @Test
-  public void testOrderOfCheckExecution() throws Exception {
+  void orderOfCheckExecution() throws Exception {
 
     final DefaultConfiguration configuration1 = createModuleConfig(AaCheck.class);
     configuration1.addProperty("id", "2");
@@ -684,7 +686,7 @@ public class TreeWalkerTest extends AbstractModuleTestSupport {
     treeWalkerConfig.addChild(configuration2);
     treeWalkerConfig.addChild(configuration1);
 
-    final List<File> files = Collections.singletonList(new File(getPath("InputTreeWalker2.java")));
+    final List<File> files = ImmutableList.of(new File(getPath("InputTreeWalker2.java")));
     final Checker checker = createChecker(treeWalkerConfig);
 
     try {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/XMLLoggerTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/XMLLoggerTest.java
@@ -34,7 +34,7 @@ import org.junit.jupiter.api.Test;
 
 /** Enter a description of class XMLLoggerTest.java. */
 // -@cs[AbbreviationAsWordInName] Test should be named as its main class.
-public class XMLLoggerTest extends AbstractXmlTestSupport {
+final class XMLLoggerTest extends AbstractXmlTestSupport {
 
   /**
    * Output stream to hold the test results. The IntelliJ IDEA issues the AutoCloseableResource
@@ -50,7 +50,7 @@ public class XMLLoggerTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testEncode() throws IOException {
+  void encode() throws IOException {
     final XMLLogger test = new XMLLogger(outStream, OutputStreamOptions.NONE);
     assertWithMessage("should be able to create XMLLogger without issue").that(test).isNotNull();
     final String[][] encodings = {
@@ -75,7 +75,7 @@ public class XMLLoggerTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testIsReference() throws IOException {
+  void isReference() throws IOException {
     final XMLLogger test = new XMLLogger(outStream, OutputStreamOptions.NONE);
     assertWithMessage("should be able to create XMLLogger without issue").that(test).isNotNull();
     final String[] references = {
@@ -97,7 +97,7 @@ public class XMLLoggerTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testCloseStream() throws Exception {
+  void closeStream() throws Exception {
     final XMLLogger logger = new XMLLogger(outStream, OutputStreamOptions.CLOSE);
     logger.auditStarted(null);
     logger.auditFinished(null);
@@ -108,7 +108,7 @@ public class XMLLoggerTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testNoCloseStream() throws Exception {
+  void noCloseStream() throws Exception {
     final XMLLogger logger = new XMLLogger(outStream, OutputStreamOptions.NONE);
     logger.auditStarted(null);
     logger.auditFinished(null);
@@ -120,7 +120,7 @@ public class XMLLoggerTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testFileStarted() throws Exception {
+  void fileStarted() throws Exception {
     final XMLLogger logger = new XMLLogger(outStream, OutputStreamOptions.CLOSE);
     logger.auditStarted(null);
     final AuditEvent ev = new AuditEvent(this, "Test.java");
@@ -131,7 +131,7 @@ public class XMLLoggerTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testFileFinished() throws Exception {
+  void fileFinished() throws Exception {
     final XMLLogger logger = new XMLLogger(outStream, OutputStreamOptions.CLOSE);
     logger.auditStarted(null);
     final AuditEvent ev = new AuditEvent(this, "Test.java");
@@ -141,7 +141,7 @@ public class XMLLoggerTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testAddError() throws Exception {
+  void addError() throws Exception {
     final XMLLogger logger = new XMLLogger(outStream, OutputStreamOptions.CLOSE);
     logger.auditStarted(null);
     final Violation violation =
@@ -156,7 +156,7 @@ public class XMLLoggerTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testAddErrorWithNullFileName() throws Exception {
+  void addErrorWithNullFileName() throws Exception {
     final XMLLogger logger = new XMLLogger(outStream, OutputStreamOptions.CLOSE);
     logger.auditStarted(null);
     final Violation violation =
@@ -170,7 +170,7 @@ public class XMLLoggerTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testAddErrorModuleId() throws Exception {
+  void addErrorModuleId() throws Exception {
     final XMLLogger logger = new XMLLogger(outStream, OutputStreamOptions.CLOSE);
     logger.auditStarted(null);
     final Violation violation =
@@ -191,7 +191,7 @@ public class XMLLoggerTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testAddErrorOnZeroColumns() throws Exception {
+  void addErrorOnZeroColumns() throws Exception {
     final XMLLogger logger = new XMLLogger(outStream, OutputStreamOptions.CLOSE);
     logger.auditStarted(null);
     final Violation violation =
@@ -206,7 +206,7 @@ public class XMLLoggerTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testAddIgnored() throws Exception {
+  void addIgnored() throws Exception {
     final XMLLogger logger = new XMLLogger(outStream, OutputStreamOptions.CLOSE);
     logger.auditStarted(null);
     final Violation violation =
@@ -219,7 +219,7 @@ public class XMLLoggerTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testAddException() throws Exception {
+  void addException() throws Exception {
     final XMLLogger logger = new XMLLogger(outStream, OutputStreamOptions.CLOSE);
     logger.auditStarted(null);
     final Violation violation =
@@ -232,7 +232,7 @@ public class XMLLoggerTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testAddExceptionWithNullFileName() throws Exception {
+  void addExceptionWithNullFileName() throws Exception {
     final XMLLogger logger = new XMLLogger(outStream, OutputStreamOptions.CLOSE);
     logger.auditStarted(null);
     final Violation violation =
@@ -245,7 +245,7 @@ public class XMLLoggerTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testAddExceptionAfterFileStarted() throws Exception {
+  void addExceptionAfterFileStarted() throws Exception {
     final XMLLogger logger = new XMLLogger(outStream, OutputStreamOptions.CLOSE);
     logger.auditStarted(null);
 
@@ -264,7 +264,7 @@ public class XMLLoggerTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testAddExceptionBeforeFileFinished() throws Exception {
+  void addExceptionBeforeFileFinished() throws Exception {
     final XMLLogger logger = new XMLLogger(outStream, OutputStreamOptions.CLOSE);
     logger.auditStarted(null);
     final Violation violation =
@@ -279,7 +279,7 @@ public class XMLLoggerTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testAddExceptionBetweenFileStartedAndFinished() throws Exception {
+  void addExceptionBetweenFileStartedAndFinished() throws Exception {
     final XMLLogger logger = new XMLLogger(outStream, OutputStreamOptions.CLOSE);
     logger.auditStarted(null);
     final Violation violation =
@@ -296,7 +296,7 @@ public class XMLLoggerTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testAuditFinishedWithoutFileFinished() throws Exception {
+  void auditFinishedWithoutFileFinished() throws Exception {
     final XMLLogger logger = new XMLLogger(outStream, OutputStreamOptions.CLOSE);
     logger.auditStarted(null);
     final AuditEvent fileStartedEvent = new AuditEvent(this, "Test.java");
@@ -314,7 +314,7 @@ public class XMLLoggerTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testNullOutputStreamOptions() {
+  void nullOutputStreamOptions() {
     try {
       final XMLLogger logger = new XMLLogger(outStream, (OutputStreamOptions) null);
       // assert required to calm down eclipse's 'The allocated object is never used' violation
@@ -328,7 +328,7 @@ public class XMLLoggerTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testFinishLocalSetup() {
+  void finishLocalSetup() {
     final XMLLogger logger = new XMLLogger(outStream, OutputStreamOptions.CLOSE);
     logger.finishLocalSetup();
     logger.auditStarted(null);
@@ -338,7 +338,7 @@ public class XMLLoggerTest extends AbstractXmlTestSupport {
 
   /** We keep this test for 100% coverage. Until #12873. */
   @Test
-  public void testCtorWithTwoParametersCloseStreamOptions() {
+  void ctorWithTwoParametersCloseStreamOptions() {
     final XMLLogger logger = new XMLLogger(outStream, AutomaticBean.OutputStreamOptions.CLOSE);
     final boolean closeStream = TestUtil.getInternalState(logger, "closeStream");
 
@@ -347,7 +347,7 @@ public class XMLLoggerTest extends AbstractXmlTestSupport {
 
   /** We keep this test for 100% coverage. Until #12873. */
   @Test
-  public void testCtorWithTwoParametersNoneStreamOptions() {
+  void ctorWithTwoParametersNoneStreamOptions() {
     final XMLLogger logger = new XMLLogger(outStream, AutomaticBean.OutputStreamOptions.NONE);
     final boolean closeStream = TestUtil.getInternalState(logger, "closeStream");
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/XdocsPropertyTypeTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/XdocsPropertyTypeTest.java
@@ -20,6 +20,7 @@
 package com.puppycrawl.tools.checkstyle;
 
 import static com.google.common.truth.Truth.assertWithMessage;
+import static java.util.stream.Collectors.toUnmodifiableSet;
 
 import com.puppycrawl.tools.checkstyle.checks.header.AbstractHeaderCheck;
 import com.puppycrawl.tools.checkstyle.internal.utils.CheckUtil;
@@ -28,14 +29,13 @@ import java.io.IOException;
 import java.util.Arrays;
 import java.util.Objects;
 import java.util.Set;
-import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import org.junit.jupiter.api.Test;
 
-public class XdocsPropertyTypeTest {
+final class XdocsPropertyTypeTest {
 
   @Test
-  public void testAllPropertyTypesAreUsed() throws IOException {
+  void allPropertyTypesAreUsed() throws IOException {
     final Set<PropertyType> propertyTypes =
         Stream.concat(
                 Stream.of(AbstractHeaderCheck.class, Checker.class),
@@ -45,7 +45,7 @@ public class XdocsPropertyTypeTest {
             .map(field -> field.getAnnotation(XdocsPropertyType.class))
             .filter(Objects::nonNull)
             .map(XdocsPropertyType::value)
-            .collect(Collectors.toUnmodifiableSet());
+            .collect(toUnmodifiableSet());
 
     assertWithMessage("All property types should be used")
         .that(propertyTypes)
@@ -53,7 +53,7 @@ public class XdocsPropertyTypeTest {
   }
 
   @Test
-  public void testAllPropertyTypesHaveDescription() {
+  void allPropertyTypesHaveDescription() {
     for (PropertyType value : PropertyType.values()) {
       assertWithMessage("Property type '%s' has no description", value)
           .that(CommonUtil.isBlank(value.getDescription()))
--- a/src/test/java/com/puppycrawl/tools/checkstyle/XmlLoaderTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/XmlLoaderTest.java
@@ -30,10 +30,10 @@ import org.junit.jupiter.api.Test;
 import org.xml.sax.SAXException;
 import org.xml.sax.XMLReader;
 
-public class XmlLoaderTest {
+final class XmlLoaderTest {
 
   @Test
-  public void testParserConfiguredSuccessfully() throws Exception {
+  void parserConfiguredSuccessfully() throws Exception {
     final DummyLoader dummyLoader = new DummyLoader(new HashMap<>(1));
     final XMLReader parser = TestUtil.getInternalState(dummyLoader, "parser");
     assertWithMessage("Invalid entity resolver")
@@ -42,14 +42,14 @@ public class XmlLoaderTest {
   }
 
   @Test
-  public void testIsProperUtilsClass() throws ReflectiveOperationException {
+  void isProperUtilsClass() throws ReflectiveOperationException {
     assertWithMessage("Constructor is not private")
         .that(isUtilsClassHasPrivateConstructor(XmlLoader.LoadExternalDtdFeatureProvider.class))
         .isTrue();
   }
 
   @Test
-  public void testResolveEntityDefault() throws Exception {
+  void resolveEntityDefault() throws Exception {
     final Map<String, String> map = new HashMap<>();
     map.put("predefined", "/google.xml");
     final DummyLoader dummyLoader = new DummyLoader(map);
@@ -59,7 +59,7 @@ public class XmlLoaderTest {
   }
 
   @Test
-  public void testResolveEntityMap() throws Exception {
+  void resolveEntityMap() throws Exception {
     final Map<String, String> map = new HashMap<>();
     map.put("predefined", "/google.xml");
     final DummyLoader dummyLoader = new DummyLoader(map);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/XpathFileGeneratorAstFilterTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/XpathFileGeneratorAstFilterTest.java
@@ -35,10 +35,10 @@ import java.nio.charset.StandardCharsets;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
 
-public class XpathFileGeneratorAstFilterTest {
+final class XpathFileGeneratorAstFilterTest {
 
   @Test
-  public void testAcceptNoToken() {
+  void acceptNoToken() {
     final Violation violation =
         new Violation(
             0, 0, 0, null, null, null, null, null, XpathFileGeneratorAstFilterTest.class, null);
@@ -56,7 +56,7 @@ public class XpathFileGeneratorAstFilterTest {
   }
 
   @Test
-  public void test() throws Exception {
+  void test() throws Exception {
     final Violation violation =
         new Violation(
             3,
@@ -87,7 +87,7 @@ public class XpathFileGeneratorAstFilterTest {
   }
 
   @Test
-  public void testNoXpathQuery() throws Exception {
+  void noXpathQuery() throws Exception {
     final Violation violation =
         new Violation(
             10,
@@ -116,7 +116,7 @@ public class XpathFileGeneratorAstFilterTest {
   }
 
   @Test
-  public void testTabWidth() throws Exception {
+  void tabWidth() throws Exception {
     final Violation violation =
         new Violation(
             6,
@@ -154,9 +154,9 @@ public class XpathFileGeneratorAstFilterTest {
    *
    * @throws Exception when code tested throws exception
    */
-  @Test
   @SuppressWarnings("unchecked")
-  public void testClearState() throws Exception {
+  @Test
+  void clearState() throws Exception {
     final Violation violation =
         new Violation(
             3,
--- a/src/test/java/com/puppycrawl/tools/checkstyle/XpathFileGeneratorAuditListenerTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/XpathFileGeneratorAuditListenerTest.java
@@ -41,7 +41,7 @@ import java.io.OutputStream;
 import java.nio.charset.StandardCharsets;
 import org.junit.jupiter.api.Test;
 
-public class XpathFileGeneratorAuditListenerTest {
+final class XpathFileGeneratorAuditListenerTest {
 
   /** OS specific line separator. */
   private static final String EOL = System.getProperty("line.separator");
@@ -90,7 +90,7 @@ public class XpathFileGeneratorAuditListenerTest {
   }
 
   @Test
-  public void testFinishLocalSetup() {
+  void finishLocalSetup() {
     final OutputStream out = new ByteArrayOutputStream();
     final XpathFileGeneratorAuditListener listener =
         new XpathFileGeneratorAuditListener(out, OutputStreamOptions.CLOSE);
@@ -103,7 +103,7 @@ public class XpathFileGeneratorAuditListenerTest {
   }
 
   @Test
-  public void testFileStarted() {
+  void fileStarted() {
     final OutputStream out = new ByteArrayOutputStream();
     final XpathFileGeneratorAuditListener listener =
         new XpathFileGeneratorAuditListener(out, OutputStreamOptions.CLOSE);
@@ -115,7 +115,7 @@ public class XpathFileGeneratorAuditListenerTest {
   }
 
   @Test
-  public void testFileFinished() {
+  void fileFinished() {
     final OutputStream out = new ByteArrayOutputStream();
     final XpathFileGeneratorAuditListener listener =
         new XpathFileGeneratorAuditListener(out, OutputStreamOptions.CLOSE);
@@ -127,7 +127,7 @@ public class XpathFileGeneratorAuditListenerTest {
   }
 
   @Test
-  public void testAddException() {
+  void addException() {
     final OutputStream out = new ByteArrayOutputStream();
     final XpathFileGeneratorAuditListener logger =
         new XpathFileGeneratorAuditListener(out, OutputStreamOptions.CLOSE);
@@ -147,7 +147,7 @@ public class XpathFileGeneratorAuditListenerTest {
   }
 
   @Test
-  public void testCorrectOne() {
+  void correctOne() {
     final AuditEvent event =
         createAuditEvent("InputXpathFileGeneratorAuditListener.java", FIRST_MESSAGE);
 
@@ -180,7 +180,7 @@ public class XpathFileGeneratorAuditListenerTest {
   }
 
   @Test
-  public void testCorrectTwo() {
+  void correctTwo() {
     final AuditEvent event1 =
         createAuditEvent("InputXpathFileGeneratorAuditListener.java", SECOND_MESSAGE);
 
@@ -227,7 +227,7 @@ public class XpathFileGeneratorAuditListenerTest {
   }
 
   @Test
-  public void testOnlyOneMatching() {
+  void onlyOneMatching() {
     final AuditEvent event1 =
         createAuditEvent(
             "InputXpathFileGeneratorAuditListener.java", 10, 5, MethodParamPadCheck.class);
@@ -268,7 +268,7 @@ public class XpathFileGeneratorAuditListenerTest {
   }
 
   @Test
-  public void testCloseStream() {
+  void closeStream() {
     final XpathFileGeneratorAuditListener listener =
         new XpathFileGeneratorAuditListener(outStream, OutputStreamOptions.CLOSE);
     listener.finishLocalSetup();
@@ -279,7 +279,7 @@ public class XpathFileGeneratorAuditListenerTest {
   }
 
   @Test
-  public void testNoCloseStream() {
+  void noCloseStream() {
     final XpathFileGeneratorAuditListener listener =
         new XpathFileGeneratorAuditListener(outStream, OutputStreamOptions.NONE);
     listener.finishLocalSetup();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/ant/CheckstyleAntTaskTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/ant/CheckstyleAntTaskTest.java
@@ -20,6 +20,7 @@
 package com.puppycrawl.tools.checkstyle.ant;
 
 import static com.google.common.truth.Truth.assertWithMessage;
+import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import com.google.common.truth.StandardSubjectBuilder;
@@ -35,7 +36,6 @@ import com.puppycrawl.tools.checkstyle.internal.testmodules.TestRootModuleChecke
 import java.io.File;
 import java.io.IOException;
 import java.net.URL;
-import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.util.Arrays;
 import java.util.List;
@@ -52,7 +52,7 @@ import org.apache.tools.ant.types.Path;
 import org.apache.tools.ant.types.resources.FileResource;
 import org.junit.jupiter.api.Test;
 
-public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
+final class CheckstyleAntTaskTest extends AbstractPathTestSupport {
 
   private static final String FLAWLESS_INPUT = "InputCheckstyleAntTaskFlawless.java";
   private static final String VIOLATED_INPUT = "InputCheckstyleAntTaskError.java";
@@ -80,7 +80,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testDefaultFlawless() throws IOException {
+  final void defaultFlawless() throws IOException {
     TestRootModuleChecker.reset();
     final CheckstyleAntTask antTask = getCheckstyleAntTask(CUSTOM_ROOT_CONFIG_FILE);
     antTask.setFile(new File(getPath(FLAWLESS_INPUT)));
@@ -92,7 +92,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testPathsOneFile() throws IOException {
+  final void pathsOneFile() throws IOException {
     // given
     TestRootModuleChecker.reset();
 
@@ -118,7 +118,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testPathsFileWithLogVerification() throws IOException {
+  final void pathsFileWithLogVerification() throws IOException {
     // given
     TestRootModuleChecker.reset();
     final CheckstyleAntTaskLogStub antTask = new CheckstyleAntTaskLogStub();
@@ -169,7 +169,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testPathsDirectoryWithNestedFile() throws IOException {
+  final void pathsDirectoryWithNestedFile() throws IOException {
     // given
     TestRootModuleChecker.reset();
 
@@ -200,7 +200,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testCustomRootModule() throws IOException {
+  final void customRootModule() throws IOException {
     TestRootModuleChecker.reset();
 
     final CheckstyleAntTask antTask = getCheckstyleAntTask(CUSTOM_ROOT_CONFIG_FILE);
@@ -213,7 +213,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testFileSet() throws IOException {
+  final void fileSet() throws IOException {
     TestRootModuleChecker.reset();
     final CheckstyleAntTask antTask = getCheckstyleAntTask(CUSTOM_ROOT_CONFIG_FILE);
     final FileSet examinationFileSet = new FileSet();
@@ -232,7 +232,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testNoConfigFile() throws IOException {
+  final void noConfigFile() throws IOException {
     final CheckstyleAntTask antTask = new CheckstyleAntTask();
     antTask.setProject(new Project());
     antTask.setFile(new File(getPath(FLAWLESS_INPUT)));
@@ -244,7 +244,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testNonExistentConfig() throws IOException {
+  final void nonExistentConfig() throws IOException {
     final CheckstyleAntTask antTask = new CheckstyleAntTask();
     antTask.setConfig(getPath(NOT_EXISTING_FILE));
     antTask.setProject(new Project());
@@ -257,7 +257,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testEmptyConfigFile() throws IOException {
+  final void emptyConfigFile() throws IOException {
     final CheckstyleAntTask antTask = new CheckstyleAntTask();
     antTask.setConfig(getPath("InputCheckstyleAntTaskEmptyConfig.xml"));
     antTask.setProject(new Project());
@@ -270,7 +270,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testNoFile() throws IOException {
+  final void noFile() throws IOException {
     final CheckstyleAntTask antTask = getCheckstyleAntTask();
     final BuildException ex =
         assertThrows(BuildException.class, antTask::execute, "BuildException is expected");
@@ -280,7 +280,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testMaxWarningExceeded() throws IOException {
+  final void maxWarningExceeded() throws IOException {
     final CheckstyleAntTask antTask = getCheckstyleAntTask();
     antTask.setFile(new File(getPath(WARNING_INPUT)));
     antTask.setMaxWarnings(0);
@@ -292,7 +292,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testMaxErrors() throws IOException {
+  final void maxErrors() throws IOException {
     TestRootModuleChecker.reset();
 
     final CheckstyleAntTask antTask = getCheckstyleAntTask(CUSTOM_ROOT_CONFIG_FILE);
@@ -306,7 +306,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testFailureProperty() throws IOException {
+  final void failureProperty() throws IOException {
     final CheckstyleAntTask antTask = new CheckstyleAntTask();
     antTask.setConfig(getPath(CONFIG_FILE));
     antTask.setFile(new File(getPath(VIOLATED_INPUT)));
@@ -330,7 +330,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testOverrideProperty() throws IOException {
+  final void overrideProperty() throws IOException {
     TestRootModuleChecker.reset();
 
     final CheckstyleAntTask antTask = getCheckstyleAntTask(CUSTOM_ROOT_CONFIG_FILE);
@@ -347,7 +347,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testExecuteIgnoredModules() throws IOException {
+  final void executeIgnoredModules() throws IOException {
     final CheckstyleAntTask antTask = getCheckstyleAntTask();
     antTask.setFile(new File(getPath(VIOLATED_INPUT)));
     antTask.setFailOnViolation(false);
@@ -390,7 +390,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testConfigurationByUrl() throws IOException {
+  final void configurationByUrl() throws IOException {
     final CheckstyleAntTask antTask = new CheckstyleAntTask();
     antTask.setProject(new Project());
     final URL url = new File(getPath(CONFIG_FILE)).toURI().toURL();
@@ -414,7 +414,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testConfigurationByResource() throws IOException {
+  final void configurationByResource() throws IOException {
     final CheckstyleAntTask antTask = new CheckstyleAntTask();
     antTask.setProject(new Project());
     antTask.setConfig(getPath(CONFIG_FILE));
@@ -437,7 +437,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testSimultaneousConfiguration() throws IOException {
+  final void simultaneousConfiguration() throws IOException {
     final File file = new File(getPath(CONFIG_FILE));
     final URL url = file.toURI().toURL();
 
@@ -453,7 +453,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testSetPropertiesFile() throws IOException {
+  final void setPropertiesFile() throws IOException {
     TestRootModuleChecker.reset();
 
     final CheckstyleAntTask antTask = getCheckstyleAntTask(CUSTOM_ROOT_CONFIG_FILE);
@@ -467,7 +467,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testSetPropertiesNonExistentFile() throws IOException {
+  final void setPropertiesNonExistentFile() throws IOException {
     final CheckstyleAntTask antTask = getCheckstyleAntTask();
     antTask.setFile(new File(getPath(FLAWLESS_INPUT)));
     antTask.setProperties(new File(getPath(NOT_EXISTING_FILE)));
@@ -479,7 +479,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testXmlOutput() throws IOException {
+  final void xmlOutput() throws IOException {
     final CheckstyleAntTask antTask = getCheckstyleAntTask();
     antTask.setFile(new File(getPath(VIOLATED_INPUT)));
     antTask.setFailOnViolation(false);
@@ -506,7 +506,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testSarifOutput() throws IOException {
+  final void sarifOutput() throws IOException {
     final CheckstyleAntTask antTask = getCheckstyleAntTask();
     antTask.setFile(new File(getPath(VIOLATED_INPUT)));
     antTask.setFailOnViolation(false);
@@ -538,7 +538,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testCreateListenerException() throws IOException {
+  final void createListenerException() throws IOException {
     final CheckstyleAntTask antTask = getCheckstyleAntTask();
     antTask.setFile(new File(getPath(FLAWLESS_INPUT)));
     final CheckstyleAntTask.Formatter formatter = new CheckstyleAntTask.Formatter();
@@ -553,7 +553,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testCreateListenerExceptionWithXmlLogger() throws IOException {
+  final void createListenerExceptionWithXmlLogger() throws IOException {
     final CheckstyleAntTask antTask = getCheckstyleAntTask();
     antTask.setFile(new File(getPath(FLAWLESS_INPUT)));
     final CheckstyleAntTask.Formatter formatter = new CheckstyleAntTask.Formatter();
@@ -571,7 +571,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testCreateListenerExceptionWithSarifLogger() throws IOException {
+  final void createListenerExceptionWithSarifLogger() throws IOException {
     final CheckstyleAntTask antTask = getCheckstyleAntTask();
     antTask.setFile(new File(getPath(FLAWLESS_INPUT)));
     final CheckstyleAntTask.Formatter formatter = new CheckstyleAntTask.Formatter();
@@ -589,7 +589,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testSetInvalidType() {
+  void setInvalidType() {
     final CheckstyleAntTask.FormatterType formatterType = new CheckstyleAntTask.FormatterType();
     final BuildException ex =
         assertThrows(
@@ -602,7 +602,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testSetFileValueByFile() throws IOException {
+  void setFileValueByFile() throws IOException {
     final String filename = getPath("InputCheckstyleAntTaskCheckstyleAntTest.properties");
     final CheckstyleAntTask.Property property = new CheckstyleAntTask.Property();
     property.setFile(new File(filename));
@@ -612,7 +612,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testDefaultLoggerListener() throws IOException {
+  void defaultLoggerListener() throws IOException {
     final CheckstyleAntTask.Formatter formatter = new CheckstyleAntTask.Formatter();
     formatter.setUseFile(false);
     assertWithMessage("Listener instance has unexpected type")
@@ -621,7 +621,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testDefaultLoggerListenerWithToFile() throws IOException {
+  void defaultLoggerListenerWithToFile() throws IOException {
     final CheckstyleAntTask.Formatter formatter = new CheckstyleAntTask.Formatter();
     formatter.setUseFile(false);
     formatter.setTofile(new File("target/"));
@@ -631,7 +631,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testXmlLoggerListener() throws IOException {
+  void xmlLoggerListener() throws IOException {
     final CheckstyleAntTask.FormatterType formatterType = new CheckstyleAntTask.FormatterType();
     formatterType.setValue("xml");
     final CheckstyleAntTask.Formatter formatter = new CheckstyleAntTask.Formatter();
@@ -643,7 +643,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testXmlLoggerListenerWithToFile() throws IOException {
+  void xmlLoggerListenerWithToFile() throws IOException {
     final CheckstyleAntTask.FormatterType formatterType = new CheckstyleAntTask.FormatterType();
     formatterType.setValue("xml");
     final CheckstyleAntTask.Formatter formatter = new CheckstyleAntTask.Formatter();
@@ -656,7 +656,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testDefaultLoggerWithNullToFile() throws IOException {
+  void defaultLoggerWithNullToFile() throws IOException {
     final CheckstyleAntTask.Formatter formatter = new CheckstyleAntTask.Formatter();
     formatter.setTofile(null);
     assertWithMessage("Listener instance has unexpected type")
@@ -665,7 +665,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testXmlLoggerWithNullToFile() throws IOException {
+  void xmlLoggerWithNullToFile() throws IOException {
     final CheckstyleAntTask.FormatterType formatterType = new CheckstyleAntTask.FormatterType();
     formatterType.setValue("xml");
     final CheckstyleAntTask.Formatter formatter = new CheckstyleAntTask.Formatter();
@@ -677,7 +677,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testSarifLoggerListener() throws IOException {
+  void sarifLoggerListener() throws IOException {
     final CheckstyleAntTask.FormatterType formatterType = new CheckstyleAntTask.FormatterType();
     formatterType.setValue("sarif");
     final CheckstyleAntTask.Formatter formatter = new CheckstyleAntTask.Formatter();
@@ -689,7 +689,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testSarifLoggerListenerWithToFile() throws IOException {
+  void sarifLoggerListenerWithToFile() throws IOException {
     final CheckstyleAntTask.FormatterType formatterType = new CheckstyleAntTask.FormatterType();
     formatterType.setValue("sarif");
     final CheckstyleAntTask.Formatter formatter = new CheckstyleAntTask.Formatter();
@@ -702,7 +702,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testSarifLoggerWithNullToFile() throws IOException {
+  void sarifLoggerWithNullToFile() throws IOException {
     final CheckstyleAntTask.FormatterType formatterType = new CheckstyleAntTask.FormatterType();
     formatterType.setValue("sarif");
     final CheckstyleAntTask.Formatter formatter = new CheckstyleAntTask.Formatter();
@@ -715,14 +715,14 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
 
   /** Testing deprecated method. */
   @Test
-  public void testCreateClasspath() {
+  void createClasspath() {
     final CheckstyleAntTask antTask = new CheckstyleAntTask();
 
     assertWithMessage("Invalid classpath").that(antTask.createClasspath().toString()).isEmpty();
   }
 
   @Test
-  public void testDestroyed() throws IOException {
+  void destroyed() throws IOException {
     TestRootModuleChecker.reset();
 
     final CheckstyleAntTask antTask = getCheckstyleAntTask(CUSTOM_ROOT_CONFIG_FILE);
@@ -736,7 +736,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testMaxWarnings() throws IOException {
+  void maxWarnings() throws IOException {
     TestRootModuleChecker.reset();
 
     final CheckstyleAntTask antTask = getCheckstyleAntTask(CUSTOM_ROOT_CONFIG_FILE);
@@ -750,7 +750,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public final void testExecuteLogOutput() throws Exception {
+  final void executeLogOutput() throws Exception {
     final URL url = new File(getPath(CONFIG_FILE)).toURI().toURL();
     final ResourceBundle bundle =
         ResourceBundle.getBundle(Definitions.CHECKSTYLE_BUNDLE, Locale.ROOT);
@@ -795,7 +795,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testCheckerException() throws IOException {
+  void checkerException() throws IOException {
     final CheckstyleAntTask antTask = new CheckstyleAntTaskStub();
     antTask.setConfig(getPath(CONFIG_FILE));
     antTask.setProject(new Project());
@@ -809,7 +809,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testLoggedTime() throws IOException {
+  void loggedTime() throws IOException {
     final CheckstyleAntTaskLogStub antTask = new CheckstyleAntTaskLogStub();
     antTask.setConfig(getPath(CONFIG_FILE));
     antTask.setProject(new Project());
@@ -835,7 +835,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
         .that(optionalMessageLevelPair.isPresent())
         .isTrue();
 
-    final long actualTime = getNumberFromLine(optionalMessageLevelPair.get().getMsg());
+    final long actualTime = getNumberFromLine(optionalMessageLevelPair.orElseThrow().getMsg());
 
     assertWithMessage(
             "Logged time in '" + expectedMsg + "' " + "must be less than the testing time")
@@ -844,7 +844,7 @@ public class CheckstyleAntTaskTest extends AbstractPathTestSupport {
   }
 
   private static List<String> readWholeFile(File outputFile) throws IOException {
-    return Files.readAllLines(outputFile.toPath(), StandardCharsets.UTF_8);
+    return Files.readAllLines(outputFile.toPath(), UTF_8);
   }
 
   private static long getNumberFromLine(String line) {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/api/AbstractCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/api/AbstractCheckTest.java
@@ -20,8 +20,9 @@
 package com.puppycrawl.tools.checkstyle.api;
 
 import static com.google.common.truth.Truth.assertWithMessage;
-import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.DetailAstImpl;
@@ -29,7 +30,6 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.io.File;
 import java.nio.charset.Charset;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;
@@ -37,7 +37,7 @@ import java.util.Set;
 import java.util.SortedSet;
 import org.junit.jupiter.api.Test;
 
-public class AbstractCheckTest extends AbstractModuleTestSupport {
+final class AbstractCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -45,7 +45,7 @@ public class AbstractCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final AbstractCheck check =
         new AbstractCheck() {
           @Override
@@ -70,7 +70,7 @@ public class AbstractCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptable() {
+  void getAcceptable() {
     final AbstractCheck check =
         new AbstractCheck() {
           @Override
@@ -95,7 +95,7 @@ public class AbstractCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommentNodes() {
+  void commentNodes() {
     final AbstractCheck check =
         new AbstractCheck() {
           @Override
@@ -118,7 +118,7 @@ public class AbstractCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokenNames() {
+  void tokenNames() {
     final AbstractCheck check =
         new AbstractCheck() {
           @Override
@@ -144,7 +144,7 @@ public class AbstractCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testVisitToken() {
+  void visitToken() {
     final VisitCounterCheck check = new VisitCounterCheck();
     // Eventually it will become clear abstract method
     check.visitToken(null);
@@ -153,7 +153,7 @@ public class AbstractCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetLine() throws Exception {
+  void getLine() throws Exception {
     final AbstractCheck check =
         new AbstractCheck() {
           @Override
@@ -181,7 +181,7 @@ public class AbstractCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetLineCodePoints() throws Exception {
+  void getLineCodePoints() throws Exception {
     final AbstractCheck check =
         new AbstractCheck() {
           @Override
@@ -213,7 +213,7 @@ public class AbstractCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetTabWidth() {
+  void getTabWidth() {
     final AbstractCheck check =
         new AbstractCheck() {
           @Override
@@ -238,7 +238,7 @@ public class AbstractCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFileContents() {
+  void fileContents() {
     final AbstractCheck check =
         new AbstractCheck() {
           @Override
@@ -268,7 +268,7 @@ public class AbstractCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final int[] defaultTokens = {TokenTypes.CLASS_DEF, TokenTypes.INTERFACE_DEF};
     final int[] acceptableTokens = {TokenTypes.CLASS_DEF, TokenTypes.INTERFACE_DEF};
     final int[] requiredTokens = {TokenTypes.CLASS_DEF, TokenTypes.INTERFACE_DEF};
@@ -302,7 +302,7 @@ public class AbstractCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClearViolations() {
+  void clearViolations() {
     final AbstractCheck check = new DummyAbstractCheck();
 
     check.log(1, "key", "args");
@@ -312,11 +312,11 @@ public class AbstractCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLineColumnLog() throws Exception {
+  void lineColumnLog() throws Exception {
     final ViolationCheck check = new ViolationCheck();
     check.configure(new DefaultConfiguration("check"));
     final File file = new File("fileName");
-    final FileText theText = new FileText(file, Collections.singletonList("test123"));
+    final FileText theText = new FileText(file, ImmutableList.of("test123"));
 
     check.setFileContents(new FileContents(theText));
     check.clearViolations();
@@ -338,11 +338,11 @@ public class AbstractCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAstLog() throws Exception {
+  void astLog() throws Exception {
     final ViolationAstCheck check = new ViolationAstCheck();
     check.configure(new DefaultConfiguration("check"));
     final File file = new File("fileName");
-    final FileText theText = new FileText(file, Collections.singletonList("test123"));
+    final FileText theText = new FileText(file, ImmutableList.of("test123"));
 
     check.setFileContents(new FileContents(theText));
     check.clearViolations();
@@ -362,7 +362,7 @@ public class AbstractCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCheck() throws Exception {
+  void check() throws Exception {
     final String[] expected = {
       "6:1: Violation.",
     };
@@ -375,10 +375,11 @@ public class AbstractCheckTest extends AbstractModuleTestSupport {
    * file as none of the checks try to modify the tokens.
    */
   @Test
-  public void testTokensAreUnmodifiable() {
+  void tokensAreUnmodifiable() {
     final DummyAbstractCheck check = new DummyAbstractCheck();
     final Set<String> tokenNameSet = check.getTokenNames();
-    assertThrows(UnsupportedOperationException.class, () -> tokenNameSet.add(""));
+    assertThatThrownBy(() -> tokenNameSet.add(""))
+        .isInstanceOf(UnsupportedOperationException.class);
   }
 
   public static final class DummyAbstractCheck extends AbstractCheck {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/api/AbstractFileSetCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/api/AbstractFileSetCheckTest.java
@@ -21,19 +21,19 @@ package com.puppycrawl.tools.checkstyle.api;
 
 import static com.google.common.truth.Truth.assertWithMessage;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.Checker;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import java.io.File;
 import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import java.util.SortedSet;
 import java.util.TreeSet;
 import org.junit.jupiter.api.Test;
 
-public class AbstractFileSetCheckTest extends AbstractModuleTestSupport {
+final class AbstractFileSetCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -41,17 +41,17 @@ public class AbstractFileSetCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTabWidth() {
+  void tabWidth() {
     final DummyFileSetCheck check = new DummyFileSetCheck();
     check.setTabWidth(12345);
     assertWithMessage("expected tab width").that(check.getTabWidth()).isEqualTo(12345);
   }
 
   @Test
-  public void testFileContents() {
+  void fileContents() {
     final FileContents contents =
         new FileContents(
-            new FileText(new File("inputAbstractFileSetCheck.tmp"), Collections.emptyList()));
+            new FileText(new File("inputAbstractFileSetCheck.tmp"), ImmutableList.of()));
     final DummyFileSetCheck check = new DummyFileSetCheck();
     check.setFileContents(contents);
     assertWithMessage("expected file contents")
@@ -60,13 +60,13 @@ public class AbstractFileSetCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testProcessSequential() throws Exception {
+  void processSequential() throws Exception {
     final DummyFileSetCheck check = new DummyFileSetCheck();
     check.configure(new DefaultConfiguration("filesetcheck"));
     check.setFileExtensions("tmp");
     final File firstFile = new File("inputAbstractFileSetCheck.tmp");
     final SortedSet<Violation> firstFileMessages =
-        check.process(firstFile, new FileText(firstFile, Collections.emptyList()));
+        check.process(firstFile, new FileText(firstFile, ImmutableList.of()));
 
     assertWithMessage("Invalid message")
         .that(firstFileMessages.first().getViolation())
@@ -86,25 +86,25 @@ public class AbstractFileSetCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNotProcessed() throws Exception {
+  void notProcessed() throws Exception {
     final ExceptionFileSetCheck check = new ExceptionFileSetCheck();
     check.setFileExtensions("java");
     final File firstFile = new File("inputAbstractFileSetCheck.tmp");
 
-    check.process(firstFile, new FileText(firstFile, Collections.emptyList()));
+    check.process(firstFile, new FileText(firstFile, ImmutableList.of()));
 
     final SortedSet<Violation> internalMessages = check.getViolations();
     assertWithMessage("Internal message should be empty").that(internalMessages).isEmpty();
   }
 
   @Test
-  public void testProcessException() throws Exception {
+  void processException() throws Exception {
     final ExceptionFileSetCheck check = new ExceptionFileSetCheck();
     check.configure(new DefaultConfiguration("filesetcheck"));
     check.setFileExtensions("tmp");
     final File firstFile = new File("inputAbstractFileSetCheck.tmp");
 
-    final FileText fileText = new FileText(firstFile, Collections.emptyList());
+    final FileText fileText = new FileText(firstFile, ImmutableList.of());
     try {
       check.process(firstFile, fileText);
       assertWithMessage("Exception is expected").fail();
@@ -118,7 +118,7 @@ public class AbstractFileSetCheckTest extends AbstractModuleTestSupport {
 
     // again to prove only 1 violation exists
     final File secondFile = new File("inputAbstractFileSetCheck.tmp");
-    final FileText fileText2 = new FileText(secondFile, Collections.emptyList());
+    final FileText fileText2 = new FileText(secondFile, ImmutableList.of());
     try {
       check.process(secondFile, fileText2);
       assertWithMessage("Exception is expected").fail();
@@ -134,7 +134,7 @@ public class AbstractFileSetCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetFileExtension() {
+  void getFileExtension() {
     final DummyFileSetCheck check = new DummyFileSetCheck();
     check.setFileExtensions("tmp", ".java");
     final String[] expectedExtensions = {".tmp", ".java"};
@@ -146,7 +146,7 @@ public class AbstractFileSetCheckTest extends AbstractModuleTestSupport {
 
   /** This javadoc exists only to suppress IntelliJ IDEA inspection. */
   @Test
-  public void testSetExtensionThrowsExceptionWhenTheyAreNull() {
+  void setExtensionThrowsExceptionWhenTheyAreNull() {
     final DummyFileSetCheck check = new DummyFileSetCheck();
     try {
       check.setFileExtensions((String[]) null);
@@ -159,7 +159,7 @@ public class AbstractFileSetCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLineColumnLog() throws Exception {
+  void lineColumnLog() throws Exception {
     final ViolationFileSetCheck check = new ViolationFileSetCheck();
     check.configure(new DefaultConfiguration("filesetcheck"));
     final File file = new File(getPath("InputAbstractFileSetLineColumn.java"));
@@ -174,7 +174,7 @@ public class AbstractFileSetCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetMessageDispatcher() {
+  void getMessageDispatcher() {
     final DummyFileSetCheck check = new DummyFileSetCheck();
     final Checker checker = new Checker();
     check.setMessageDispatcher(checker);
@@ -185,7 +185,7 @@ public class AbstractFileSetCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCheck() throws Exception {
+  void check() throws Exception {
     final String[] expected = {
       "1:1: Violation.",
     };
@@ -193,7 +193,7 @@ public class AbstractFileSetCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMultiFileFireErrors() throws Exception {
+  void multiFileFireErrors() throws Exception {
     final MultiFileViolationFileSetCheck check = new MultiFileViolationFileSetCheck();
     check.configure(new DefaultConfiguration("filesetcheck"));
     final ViolationDispatcher dispatcher = new ViolationDispatcher();
@@ -227,7 +227,7 @@ public class AbstractFileSetCheckTest extends AbstractModuleTestSupport {
    * as none of the checks try to modify the fileExtensions.
    */
   @Test
-  public void testCopiedArrayIsReturned() {
+  void copiedArrayIsReturned() {
     final DummyFileSetCheck check = new DummyFileSetCheck();
     check.setFileExtensions(".tmp");
     assertWithMessage("Extensions should be copied")
--- a/src/test/java/com/puppycrawl/tools/checkstyle/api/AbstractViolationReporterTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/api/AbstractViolationReporterTest.java
@@ -28,7 +28,7 @@ import java.util.SortedSet;
 import org.junit.jupiter.api.Test;
 
 /** Tests to ensure that default message bundle is determined correctly. */
-public class AbstractViolationReporterTest {
+final class AbstractViolationReporterTest {
 
   private final AbstractCheck emptyCheck = new EmptyCheck();
 
@@ -37,7 +37,7 @@ public class AbstractViolationReporterTest {
   }
 
   @Test
-  public void testGetMessageBundleWithPackage() throws Exception {
+  void getMessageBundleWithPackage() throws Exception {
     assertWithMessage("violation bundle differs from expected")
         .that(
             TestUtil.<String>invokeStaticMethod(
@@ -48,7 +48,7 @@ public class AbstractViolationReporterTest {
   }
 
   @Test
-  public void testGetMessageBundleWithoutPackage() throws Exception {
+  void getMessageBundleWithoutPackage() throws Exception {
     assertWithMessage("violation bundle differs from expected")
         .that(
             TestUtil.<String>invokeStaticMethod(
@@ -57,13 +57,13 @@ public class AbstractViolationReporterTest {
   }
 
   @Test
-  public void testCustomId() {
+  void customId() {
     emptyCheck.setId("MyId");
     assertWithMessage("Id differs from expected").that(emptyCheck.getId()).isEqualTo("MyId");
   }
 
   @Test
-  public void testSeverity() throws Exception {
+  void severity() throws Exception {
     final DefaultConfiguration config = createModuleConfig(emptyCheck.getClass());
     config.addMessage("severity", "error");
     emptyCheck.configure(config);
@@ -75,7 +75,7 @@ public class AbstractViolationReporterTest {
   }
 
   @Test
-  public void testCustomMessage() throws Exception {
+  void customMessage() throws Exception {
     final DefaultConfiguration config = createModuleConfig(emptyCheck.getClass());
     config.addMessage("msgKey", "This is a custom violation.");
     emptyCheck.configure(config);
@@ -91,7 +91,7 @@ public class AbstractViolationReporterTest {
   }
 
   @Test
-  public void testCustomMessageWithParameters() throws Exception {
+  void customMessageWithParameters() throws Exception {
     final DefaultConfiguration config = createModuleConfig(emptyCheck.getClass());
     config.addMessage("msgKey", "This is a custom violation with {0}.");
     emptyCheck.configure(config);
@@ -107,7 +107,7 @@ public class AbstractViolationReporterTest {
   }
 
   @Test
-  public void testCustomMessageWithParametersNegative() throws Exception {
+  void customMessageWithParametersNegative() throws Exception {
     final DefaultConfiguration config = createModuleConfig(emptyCheck.getClass());
     config.addMessage("msgKey", "This is a custom violation {0.");
     emptyCheck.configure(config);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/api/AuditEventTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/api/AuditEventTest.java
@@ -24,10 +24,10 @@ import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import org.junit.jupiter.api.Test;
 
-public class AuditEventTest {
+final class AuditEventTest {
 
   @Test
-  public void test() {
+  void test() {
     final AuditEvent event = new AuditEvent(getClass());
 
     assertWithMessage("invalid file name").that(event.getFileName()).isNull();
@@ -39,7 +39,7 @@ public class AuditEventTest {
   }
 
   @Test
-  public void testNoSource() {
+  void noSource() {
     final IllegalArgumentException ex =
         assertThrows(
             IllegalArgumentException.class,
@@ -49,7 +49,7 @@ public class AuditEventTest {
   }
 
   @Test
-  public void testFullConstructor() {
+  void fullConstructor() {
     final Violation message =
         new Violation(
             1,
--- a/src/test/java/com/puppycrawl/tools/checkstyle/api/BeforeExecutionFileFilterSetTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/api/BeforeExecutionFileFilterSetTest.java
@@ -20,17 +20,17 @@
 package com.puppycrawl.tools.checkstyle.api;
 
 import static com.google.common.truth.Truth.assertWithMessage;
-import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 import com.puppycrawl.tools.checkstyle.filefilters.BeforeExecutionExclusionFileFilter;
 import java.util.Set;
 import java.util.regex.Pattern;
 import org.junit.jupiter.api.Test;
 
-public class BeforeExecutionFileFilterSetTest {
+final class BeforeExecutionFileFilterSetTest {
 
   @Test
-  public void testRemoveFilters() {
+  void removeFilters() {
     final BeforeExecutionFileFilterSet filterSet = new BeforeExecutionFileFilterSet();
     final BeforeExecutionFileFilter filter = new BeforeExecutionExclusionFileFilter();
     filterSet.addBeforeExecutionFileFilter(filter);
@@ -39,7 +39,7 @@ public class BeforeExecutionFileFilterSetTest {
   }
 
   @Test
-  public void testAccept() {
+  void accept() {
     final String fileName = "BAD";
     final BeforeExecutionExclusionFileFilter filter = new BeforeExecutionExclusionFileFilter();
     filter.setFileNamePattern(Pattern.compile(fileName));
@@ -52,7 +52,7 @@ public class BeforeExecutionFileFilterSetTest {
   }
 
   @Test
-  public void testReject() {
+  void reject() {
     final String fileName = "Test";
     final BeforeExecutionExclusionFileFilter filter = new BeforeExecutionExclusionFileFilter();
     filter.setFileNamePattern(Pattern.compile(fileName));
@@ -65,7 +65,7 @@ public class BeforeExecutionFileFilterSetTest {
   }
 
   @Test
-  public void testGetFilters2() {
+  void getFilters2() {
     final BeforeExecutionFileFilterSet filterSet = new BeforeExecutionFileFilterSet();
     filterSet.addBeforeExecutionFileFilter(new BeforeExecutionExclusionFileFilter());
     assertWithMessage("size is the same")
@@ -74,14 +74,14 @@ public class BeforeExecutionFileFilterSetTest {
   }
 
   @Test
-  public void testToString2() {
+  void toString2() {
     final BeforeExecutionFileFilterSet filterSet = new BeforeExecutionFileFilterSet();
     filterSet.addBeforeExecutionFileFilter(new BeforeExecutionExclusionFileFilter());
     assertWithMessage("size is the same").that(filterSet.toString()).isNotNull();
   }
 
   @Test
-  public void testClear() {
+  void clear() {
     final BeforeExecutionFileFilterSet filterSet = new BeforeExecutionFileFilterSet();
     filterSet.addBeforeExecutionFileFilter(new BeforeExecutionExclusionFileFilter());
 
@@ -102,12 +102,13 @@ public class BeforeExecutionFileFilterSetTest {
     done for the time being
   */
   @Test
-  public void testUnmodifiableSet() {
+  void unmodifiableSet() {
     final BeforeExecutionFileFilterSet filterSet = new BeforeExecutionFileFilterSet();
     final BeforeExecutionFileFilter filter = new BeforeExecutionExclusionFileFilter();
     filterSet.addBeforeExecutionFileFilter(filter);
     final Set<BeforeExecutionFileFilter> excFilterSet = filterSet.getBeforeExecutionFileFilters();
-    assertThrows(UnsupportedOperationException.class, () -> excFilterSet.add(filter));
+    assertThatThrownBy(() -> excFilterSet.add(filter))
+        .isInstanceOf(UnsupportedOperationException.class);
   }
 
   /*
@@ -115,7 +116,7 @@ public class BeforeExecutionFileFilterSetTest {
     useful for third party integrations.
   */
   @Test
-  public void testEmptyToString() {
+  void emptyToString() {
     final BeforeExecutionFileFilterSet filterSet = new BeforeExecutionFileFilterSet();
     assertWithMessage("toString() result shouldn't be an empty string")
         .that(filterSet.toString())
--- a/src/test/java/com/puppycrawl/tools/checkstyle/api/CommentTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/api/CommentTest.java
@@ -23,10 +23,10 @@ import static com.google.common.truth.Truth.assertWithMessage;
 
 import org.junit.jupiter.api.Test;
 
-public class CommentTest {
+final class CommentTest {
 
   @Test
-  public void test() {
+  void test() {
     final String[] text = {"test"};
     final Comment comment = new Comment(text, 1, 2, 3);
 
@@ -42,7 +42,7 @@ public class CommentTest {
   }
 
   @Test
-  public void testIntersects() {
+  void intersects() {
     final String[] text = {"test", "test"};
     final Comment comment = new Comment(text, 2, 4, 4);
 
@@ -55,7 +55,7 @@ public class CommentTest {
   }
 
   @Test
-  public void testIntersects2() {
+  void intersects2() {
     final String[] text = {"a"};
     final Comment comment = new Comment(text, 2, 2, 2);
 
@@ -63,7 +63,7 @@ public class CommentTest {
   }
 
   @Test
-  public void testIntersects3() {
+  void intersects3() {
     final String[] text = {"test"};
     final Comment comment = new Comment(text, 1, 1, 2);
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/api/FileContentsTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/api/FileContentsTest.java
@@ -20,21 +20,21 @@
 package com.puppycrawl.tools.checkstyle.api;
 
 import static com.google.common.truth.Truth.assertWithMessage;
-import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.internal.utils.TestUtil;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
 
-public class FileContentsTest {
+final class FileContentsTest {
 
   @Test
-  public void testTextFileName() {
+  void textFileName() {
     final FileContents fileContents =
         new FileContents(new FileText(new File("filename"), Arrays.asList("123", "456")));
 
@@ -48,36 +48,35 @@ public class FileContentsTest {
   }
 
   @Test
-  public void testIsLineBlank() {
+  void isLineBlank() {
     assertWithMessage("Invalid result")
         .that(
-            new FileContents(new FileText(new File("filename"), Collections.singletonList("123")))
+            new FileContents(new FileText(new File("filename"), ImmutableList.of("123")))
                 .lineIsBlank(0))
         .isFalse();
     assertWithMessage("Invalid result")
         .that(
-            new FileContents(new FileText(new File("filename"), Collections.singletonList("")))
+            new FileContents(new FileText(new File("filename"), ImmutableList.of("")))
                 .lineIsBlank(0))
         .isTrue();
   }
 
   @Test
-  public void testLineIsComment() {
+  void lineIsComment() {
     assertWithMessage("Invalid result")
         .that(
-            new FileContents(new FileText(new File("filename"), Collections.singletonList("123")))
+            new FileContents(new FileText(new File("filename"), ImmutableList.of("123")))
                 .lineIsComment(0))
         .isFalse();
     assertWithMessage("Invalid result")
         .that(
-            new FileContents(
-                    new FileText(new File("filename"), Collections.singletonList(" // abc")))
+            new FileContents(new FileText(new File("filename"), ImmutableList.of(" // abc")))
                 .lineIsComment(0))
         .isTrue();
   }
 
   @Test
-  public void testDeprecatedAbbreviatedMethod() {
+  void deprecatedAbbreviatedMethod() {
     // just to make UT coverage 100%
     final FileContents fileContents =
         new FileContents(new FileText(new File("filename"), Arrays.asList("123", "456")));
@@ -93,10 +92,10 @@ public class FileContentsTest {
   }
 
   @Test
-  public void testSinglelineCommentNotIntersect() {
+  void singlelineCommentNotIntersect() {
     // just to make UT coverage 100%
     final FileContents fileContents =
-        new FileContents(new FileText(new File("filename"), Collections.singletonList("  //  ")));
+        new FileContents(new FileText(new File("filename"), ImmutableList.of("  //  ")));
     fileContents.reportSingleLineComment(1, 2);
     assertWithMessage("Should return false when there is no intersection")
         .that(fileContents.hasIntersectionWithComment(1, 0, 1, 1))
@@ -104,10 +103,10 @@ public class FileContentsTest {
   }
 
   @Test
-  public void testSinglelineCommentIntersect() {
+  void singlelineCommentIntersect() {
     // just to make UT coverage 100%
     final FileContents fileContents =
-        new FileContents(new FileText(new File("filename"), Collections.singletonList("  //   ")));
+        new FileContents(new FileText(new File("filename"), ImmutableList.of("  //   ")));
     fileContents.reportSingleLineComment("type", 1, 2);
     assertWithMessage("Should return true when comments intersect")
         .that(fileContents.hasIntersectionWithComment(1, 5, 1, 6))
@@ -115,9 +114,9 @@ public class FileContentsTest {
   }
 
   @Test
-  public void testReportCppComment() {
+  void reportCppComment() {
     final FileContents fileContents =
-        new FileContents(new FileText(new File("filename"), Collections.singletonList("   //  ")));
+        new FileContents(new FileText(new File("filename"), ImmutableList.of("   //  ")));
     fileContents.reportSingleLineComment(1, 2);
     final Map<Integer, TextBlock> cppComments = fileContents.getSingleLineComments();
 
@@ -127,7 +126,7 @@ public class FileContentsTest {
   }
 
   @Test
-  public void testHasIntersectionWithSingleLineComment() {
+  void hasIntersectionWithSingleLineComment() {
     final FileContents fileContents =
         new FileContents(
             new FileText(
@@ -141,9 +140,9 @@ public class FileContentsTest {
   }
 
   @Test
-  public void testReportComment() {
+  void reportComment() {
     final FileContents fileContents =
-        new FileContents(new FileText(new File("filename"), Collections.singletonList("  //   ")));
+        new FileContents(new FileText(new File("filename"), ImmutableList.of("  //   ")));
     fileContents.reportBlockComment("type", 1, 2, 1, 2);
     final Map<Integer, List<TextBlock>> comments = fileContents.getBlockComments();
 
@@ -153,10 +152,9 @@ public class FileContentsTest {
   }
 
   @Test
-  public void testReportBlockCommentSameLine() {
+  void reportBlockCommentSameLine() {
     final FileContents fileContents =
-        new FileContents(
-            new FileText(new File("filename"), Collections.singletonList("/* a */ /* b */ ")));
+        new FileContents(new FileText(new File("filename"), ImmutableList.of("/* a */ /* b */ ")));
     fileContents.reportBlockComment("type", 1, 0, 1, 6);
     fileContents.reportBlockComment("type", 1, 8, 1, 14);
     final Map<Integer, List<TextBlock>> comments = fileContents.getBlockComments();
@@ -171,7 +169,7 @@ public class FileContentsTest {
   }
 
   @Test
-  public void testReportBlockCommentMultiLine() {
+  void reportBlockCommentMultiLine() {
     final FileContents fileContents =
         new FileContents(new FileText(new File("filename"), Arrays.asList("/*", "c", "*/")));
     fileContents.reportBlockComment("type", 1, 0, 3, 1);
@@ -180,12 +178,11 @@ public class FileContentsTest {
     assertWithMessage("Invalid comment")
         .that(comments.get(1).toString())
         .isEqualTo(
-            Collections.singletonList(new Comment(new String[] {"/*", "c", "*/"}, 0, 3, 1))
-                .toString());
+            ImmutableList.of(new Comment(new String[] {"/*", "c", "*/"}, 0, 3, 1)).toString());
   }
 
   @Test
-  public void testReportBlockCommentJavadoc() {
+  void reportBlockCommentJavadoc() {
     final FileContents fileContents =
         new FileContents(
             new FileText(
@@ -203,7 +200,7 @@ public class FileContentsTest {
   }
 
   @Test
-  public void testHasIntersectionWithBlockComment() {
+  void hasIntersectionWithBlockComment() {
     final FileContents fileContents =
         new FileContents(
             new FileText(
@@ -218,7 +215,7 @@ public class FileContentsTest {
   }
 
   @Test
-  public void testHasIntersectionWithBlockComment2() {
+  void hasIntersectionWithBlockComment2() {
     final FileContents fileContents =
         new FileContents(
             new FileText(new File("filename"), Arrays.asList("  /* */    ", "    ", " ")));
@@ -230,10 +227,9 @@ public class FileContentsTest {
   }
 
   @Test
-  public void testReportJavadocComment() {
+  void reportJavadocComment() {
     final FileContents fileContents =
-        new FileContents(
-            new FileText(new File("filename"), Collections.singletonList("  /** */   ")));
+        new FileContents(new FileText(new File("filename"), ImmutableList.of("  /** */   ")));
     fileContents.reportBlockComment(1, 2, 1, 6);
     final TextBlock comment = fileContents.getJavadocBefore(2);
 
@@ -243,10 +239,9 @@ public class FileContentsTest {
   }
 
   @Test
-  public void testReportJavadocComment2() {
+  void reportJavadocComment2() {
     final FileContents fileContents =
-        new FileContents(
-            new FileText(new File("filename"), Collections.singletonList("  /** */   ")));
+        new FileContents(new FileText(new File("filename"), ImmutableList.of("  /** */   ")));
     fileContents.reportBlockComment(1, 2, 1, 6);
     final TextBlock comment = fileContents.getJavadocBefore(2);
 
@@ -261,10 +256,9 @@ public class FileContentsTest {
    */
   @Deprecated(since = "10.2")
   @Test
-  public void testInPackageInfo() {
+  void inPackageInfo() {
     final FileContents fileContents =
-        new FileContents(
-            new FileText(new File("package-info.java"), Collections.singletonList("  //   ")));
+        new FileContents(new FileText(new File("package-info.java"), ImmutableList.of("  //   ")));
 
     assertWithMessage("Should return true when in package info")
         .that(fileContents.inPackageInfo())
@@ -277,10 +271,10 @@ public class FileContentsTest {
    */
   @Deprecated(since = "10.2")
   @Test
-  public void testNotInPackageInfo() {
+  void notInPackageInfo() {
     final FileContents fileContents =
         new FileContents(
-            new FileText(new File("some-package-info.java"), Collections.singletonList("  //   ")));
+            new FileText(new File("some-package-info.java"), ImmutableList.of("  //   ")));
 
     assertWithMessage("Should return false when not in package info")
         .that(fileContents.inPackageInfo())
@@ -288,9 +282,9 @@ public class FileContentsTest {
   }
 
   @Test
-  public void testGetJavadocBefore() {
+  void getJavadocBefore() {
     final FileContents fileContents =
-        new FileContents(new FileText(new File("filename"), Collections.singletonList("    ")));
+        new FileContents(new FileText(new File("filename"), ImmutableList.of("    ")));
     final Map<Integer, TextBlock> javadoc = new HashMap<>();
     javadoc.put(0, new Comment(new String[] {"// "}, 2, 1, 2));
     TestUtil.setInternalState(fileContents, "javadocComments", javadoc);
@@ -302,7 +296,7 @@ public class FileContentsTest {
   }
 
   @Test
-  public void testExtractBlockComment() {
+  void extractBlockComment() {
     final FileContents fileContents =
         new FileContents(
             new FileText(
@@ -318,14 +312,14 @@ public class FileContentsTest {
   }
 
   @Test
-  public void testHasIntersectionEarlyOut() throws Exception {
+  void hasIntersectionEarlyOut() throws Exception {
     final FileContents fileContents =
-        new FileContents(new FileText(new File("filename"), Collections.emptyList()));
+        new FileContents(new FileText(new File("filename"), ImmutableList.of()));
     final Map<Integer, List<TextBlock>> clangComments =
         TestUtil.getInternalState(fileContents, "clangComments");
     final TextBlock textBlock = new Comment(new String[] {""}, 1, 1, 1);
-    clangComments.put(1, Collections.singletonList(textBlock));
-    clangComments.put(2, Collections.emptyList());
+    clangComments.put(1, ImmutableList.of(textBlock));
+    clangComments.put(2, ImmutableList.of());
 
     assertWithMessage("Invalid results")
         .that(
@@ -335,22 +329,22 @@ public class FileContentsTest {
   }
 
   @Test
-  public void testUnmodifiableGetSingleLineComment() {
+  void unmodifiableGetSingleLineComment() {
     final FileContents cppComments =
         new FileContents(
             new FileText(new File("filename"), Arrays.asList("// comment ", " A + B ", " ")));
     cppComments.reportSingleLineComment(1, 0);
     final Map<Integer, TextBlock> comments = cppComments.getSingleLineComments();
-    assertThrows(UnsupportedOperationException.class, () -> comments.remove(0));
+    assertThatThrownBy(() -> comments.remove(0)).isInstanceOf(UnsupportedOperationException.class);
   }
 
   @Test
-  public void testUnmodifiableGetBlockComments() {
+  void unmodifiableGetBlockComments() {
     final FileContents clangComments =
         new FileContents(
             new FileText(new File("filename"), Arrays.asList("/* comment ", " ", " comment */")));
     clangComments.reportBlockComment(1, 0, 3, 9);
     final Map<Integer, List<TextBlock>> comments = clangComments.getBlockComments();
-    assertThrows(UnsupportedOperationException.class, () -> comments.remove(0));
+    assertThatThrownBy(() -> comments.remove(0)).isInstanceOf(UnsupportedOperationException.class);
   }
 }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/api/FileSetCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/api/FileSetCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.io.File;
 import org.junit.jupiter.api.Test;
 
-public class FileSetCheckTest extends AbstractModuleTestSupport {
+final class FileSetCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class FileSetCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTranslation() throws Exception {
+  void translation() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputFileSetIllegalTokens.java"), expected);
 
@@ -44,7 +44,7 @@ public class FileSetCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testProcessCallsFinishBeforeCallingDestroy() throws Exception {
+  void processCallsFinishBeforeCallingDestroy() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputFileSetIllegalTokens.java"), expected);
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/api/FileTextTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/api/FileTextTest.java
@@ -20,7 +20,9 @@
 package com.puppycrawl.tools.checkstyle.api;
 
 import static com.google.common.truth.Truth.assertWithMessage;
+import static java.nio.charset.StandardCharsets.ISO_8859_1;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.AbstractPathTestSupport;
 import com.puppycrawl.tools.checkstyle.internal.utils.CheckUtil;
 import com.puppycrawl.tools.checkstyle.internal.utils.TestUtil;
@@ -30,11 +32,10 @@ import java.io.IOException;
 import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class FileTextTest extends AbstractPathTestSupport {
+final class FileTextTest extends AbstractPathTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -42,7 +43,7 @@ public class FileTextTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testUnsupportedCharset() throws IOException {
+  void unsupportedCharset() throws IOException {
     // just to make UT coverage 100%
     final String charsetName = "STRANGE_CHARSET";
     final File file = new File("any name");
@@ -58,7 +59,7 @@ public class FileTextTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testFileNotFound() throws IOException {
+  void fileNotFound() throws IOException {
     final String charsetName = StandardCharsets.ISO_8859_1.name();
     final File file = new File("any name");
     try {
@@ -73,7 +74,7 @@ public class FileTextTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testSupportedCharset() throws IOException {
+  void supportedCharset() throws IOException {
     final String charsetName = StandardCharsets.ISO_8859_1.name();
     final FileText fileText =
         new FileText(new File(getPath("InputFileTextImportControl.xml")), charsetName);
@@ -83,7 +84,7 @@ public class FileTextTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testLineColumnBeforeCopyConstructor() throws IOException {
+  void lineColumnBeforeCopyConstructor() throws IOException {
     final String charsetName = StandardCharsets.ISO_8859_1.name();
     final FileText fileText =
         new FileText(new File(getPath("InputFileTextImportControl.xml")), charsetName);
@@ -97,8 +98,8 @@ public class FileTextTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testLineColumnAfterCopyConstructor() throws IOException {
-    final Charset charset = StandardCharsets.ISO_8859_1;
+  void lineColumnAfterCopyConstructor() throws IOException {
+    final Charset charset = ISO_8859_1;
     final String filepath = getPath("InputFileTextImportControl.xml");
     final FileText fileText = new FileText(new File(filepath), charset.name());
     final FileText copy = new FileText(fileText);
@@ -115,7 +116,7 @@ public class FileTextTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testLineColumnAtTheStartOfFile() throws IOException {
+  void lineColumnAtTheStartOfFile() throws IOException {
     final String charsetName = StandardCharsets.ISO_8859_1.name();
     final FileText fileText =
         new FileText(new File(getPath("InputFileTextImportControl.xml")), charsetName);
@@ -126,15 +127,15 @@ public class FileTextTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testLines() throws IOException {
-    final List<String> lines = Collections.singletonList("abc");
+  void lines() throws IOException {
+    final List<String> lines = ImmutableList.of("abc");
     final FileText fileText =
         new FileText(new File(getPath("InputFileTextImportControl.xml")), lines);
     assertWithMessage("Invalid line").that(fileText.toLinesArray()).isEqualTo(new String[] {"abc"});
   }
 
   @Test
-  public void testFindLineBreaks() throws Exception {
+  void findLineBreaks() throws Exception {
     final FileText fileText = new FileText(new File("fileName"), Arrays.asList("1", "2"));
 
     assertWithMessage("Invalid line breaks")
@@ -156,8 +157,8 @@ public class FileTextTest extends AbstractPathTestSupport {
    * @throws Exception if there is an error.
    */
   @Test
-  public void testFindLineBreaksCache() throws Exception {
-    final FileText fileText = new FileText(new File("fileName"), Collections.emptyList());
+  void findLineBreaksCache() throws Exception {
+    final FileText fileText = new FileText(new File("fileName"), ImmutableList.of());
     final int[] lineBreaks = {5};
     TestUtil.setInternalState(fileText, "lineBreaks", lineBreaks);
     // produces NPE if used
@@ -169,8 +170,8 @@ public class FileTextTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testCharsetAfterCopyConstructor() throws IOException {
-    final Charset charset = StandardCharsets.ISO_8859_1;
+  void charsetAfterCopyConstructor() throws IOException {
+    final Charset charset = ISO_8859_1;
     final String filepath = getPath("InputFileTextImportControl.xml");
     final FileText fileText = new FileText(new File(filepath), charset.name());
     final FileText copy = new FileText(fileText);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/api/FilterSetTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/api/FilterSetTest.java
@@ -20,24 +20,24 @@
 package com.puppycrawl.tools.checkstyle.api;
 
 import static com.google.common.truth.Truth.assertWithMessage;
-import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 import com.puppycrawl.tools.checkstyle.filters.SeverityMatchFilter;
 import java.util.Objects;
 import java.util.Set;
 import org.junit.jupiter.api.Test;
 
-public class FilterSetTest {
+final class FilterSetTest {
 
   @Test
-  public void testGetFilters() {
+  void getFilters() {
     final FilterSet filterSet = new FilterSet();
     filterSet.addFilter(new SeverityMatchFilter());
     assertWithMessage("Invalid filter set size").that(filterSet.getFilters()).hasSize(1);
   }
 
   @Test
-  public void testRemoveFilters() {
+  void removeFilters() {
     final FilterSet filterSet = new FilterSet();
     final Filter filter = new SeverityMatchFilter();
     filterSet.addFilter(filter);
@@ -46,14 +46,14 @@ public class FilterSetTest {
   }
 
   @Test
-  public void testToString() {
+  void testToString() {
     final FilterSet filterSet = new FilterSet();
     filterSet.addFilter(new SeverityMatchFilter());
     assertWithMessage("Invalid filter set size").that(filterSet.toString()).isNotNull();
   }
 
   @Test
-  public void testClear() {
+  void clear() {
     final FilterSet filterSet = new FilterSet();
     filterSet.addFilter(new SeverityMatchFilter());
 
@@ -65,21 +65,21 @@ public class FilterSetTest {
   }
 
   @Test
-  public void testAccept() {
+  void accept() {
     final FilterSet filterSet = new FilterSet();
     filterSet.addFilter(new DummyFilter(true));
     assertWithMessage("invalid accept response").that(filterSet.accept(null)).isTrue();
   }
 
   @Test
-  public void testNotAccept() {
+  void notAccept() {
     final FilterSet filterSet = new FilterSet();
     filterSet.addFilter(new DummyFilter(false));
     assertWithMessage("invalid accept response").that(filterSet.accept(null)).isFalse();
   }
 
   @Test
-  public void testNotAcceptEvenIfOneAccepts() {
+  void notAcceptEvenIfOneAccepts() {
     final FilterSet filterSet = new FilterSet();
     filterSet.addFilter(new DummyFilter(true));
     filterSet.addFilter(new DummyFilter(false));
@@ -92,12 +92,13 @@ public class FilterSetTest {
     done for the time being
   */
   @Test
-  public void testUnmodifiableSet() {
+  void unmodifiableSet() {
     final FilterSet filterSet = new FilterSet();
     final Filter filter = new FilterSet();
     filterSet.addFilter(filter);
     final Set<Filter> subFilterSet = filterSet.getFilters();
-    assertThrows(UnsupportedOperationException.class, () -> subFilterSet.add(filter));
+    assertThatThrownBy(() -> subFilterSet.add(filter))
+        .isInstanceOf(UnsupportedOperationException.class);
   }
 
   /*
@@ -105,7 +106,7 @@ public class FilterSetTest {
     be useful for third party integrations
   */
   @Test
-  public void testEmptyToString() {
+  void emptyToString() {
     final FilterSet filterSet = new FilterSet();
     assertWithMessage("toString() result shouldn't be an empty string")
         .that(filterSet.toString())
--- a/src/test/java/com/puppycrawl/tools/checkstyle/api/FullIdentTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/api/FullIdentTest.java
@@ -30,7 +30,7 @@ import java.io.File;
 import java.nio.charset.StandardCharsets;
 import org.junit.jupiter.api.Test;
 
-public class FullIdentTest extends AbstractModuleTestSupport {
+final class FullIdentTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -38,7 +38,7 @@ public class FullIdentTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testToString() {
+  void testToString() {
     final DetailAstImpl ast = new DetailAstImpl();
     ast.setType(TokenTypes.LITERAL_NEW);
     ast.setColumnNo(14);
@@ -60,7 +60,7 @@ public class FullIdentTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCreateFullIdentBelow() {
+  void createFullIdentBelow() {
     final DetailAST ast = new DetailAstImpl();
 
     final FullIdent indent = FullIdent.createFullIdentBelow(ast);
@@ -68,7 +68,7 @@ public class FullIdentTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetDetailAst() throws Exception {
+  void getDetailAst() throws Exception {
     final FileText testFileText =
         new FileText(
             new File(getPath("InputFullIdentTestArrayType.java")).getAbsoluteFile(),
@@ -83,7 +83,7 @@ public class FullIdentTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonValidCoordinatesWithNegative() {
+  void nonValidCoordinatesWithNegative() {
     final FullIdent fullIdent = prepareFullIdentWithCoordinates(14, 15);
     assertWithMessage("Invalid full indent")
         .that(fullIdent.toString())
@@ -91,7 +91,7 @@ public class FullIdentTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonValidCoordinatesWithZero() {
+  void nonValidCoordinatesWithZero() {
     final FullIdent fullIdent = prepareFullIdentWithCoordinates(0, 0);
     assertWithMessage("Invalid full indent")
         .that(fullIdent.toString())
@@ -99,7 +99,7 @@ public class FullIdentTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithArrayCreateFullIdentWithArrayDeclare() throws Exception {
+  void withArrayCreateFullIdentWithArrayDeclare() throws Exception {
     final FileText testFileText =
         new FileText(
             new File(getPath("InputFullIdentTestArrayType.java")).getAbsoluteFile(),
@@ -118,7 +118,7 @@ public class FullIdentTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFullIdentAnnotation() throws Exception {
+  void fullIdentAnnotation() throws Exception {
     final FileText testFileText =
         new FileText(
             new File(getPath("InputFullIdentAnnotation.java")).getAbsoluteFile(),
@@ -146,7 +146,7 @@ public class FullIdentTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFullIdentArrayInit() throws Exception {
+  void fullIdentArrayInit() throws Exception {
     final FileText testFileText =
         new FileText(
             new File(getPath("InputFullIdentArrayInit.java")).getAbsoluteFile(),
@@ -203,7 +203,7 @@ public class FullIdentTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testReturnNoAnnotation() throws Exception {
+  void returnNoAnnotation() throws Exception {
     final FileText testFileText =
         new FileText(
             new File(getPath("InputFullIdentReturnNoAnnotation.java")).getAbsoluteFile(),
@@ -216,7 +216,7 @@ public class FullIdentTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFullyQualifiedStringArray() throws Exception {
+  void fullyQualifiedStringArray() throws Exception {
     final FileText testFileText =
         new FileText(
             new File(getPath("InputFullIdentFullyQualifiedStringArray.java")).getAbsoluteFile(),
@@ -236,7 +236,7 @@ public class FullIdentTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCreateFullIdentBelow2() throws Exception {
+  void createFullIdentBelow2() throws Exception {
     final String[] expected = {
       "9:1: " + getCheckMessage(ImportOrderCheck.class, MSG_ORDERING, "java.util.HashMap"),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/api/JavadocTokenTypesTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/api/JavadocTokenTypesTest.java
@@ -25,17 +25,17 @@ import static com.puppycrawl.tools.checkstyle.internal.utils.TestUtil.isUtilsCla
 import java.lang.reflect.Field;
 import org.junit.jupiter.api.Test;
 
-public class JavadocTokenTypesTest {
+final class JavadocTokenTypesTest {
 
   @Test
-  public void testIsProperUtilsClass() throws ReflectiveOperationException {
+  void isProperUtilsClass() throws ReflectiveOperationException {
     assertWithMessage("Constructor is not private")
         .that(isUtilsClassHasPrivateConstructor(JavadocTokenTypes.class))
         .isTrue();
   }
 
   @Test
-  public void testTokenValues() {
+  void tokenValues() {
     final String msg =
         "Please ensure that token values in `JavadocTokenTypes.java` have not" + " changed.";
     assertWithMessage(msg).that(JavadocTokenTypes.RETURN_LITERAL).isEqualTo(11);
@@ -222,7 +222,7 @@ public class JavadocTokenTypesTest {
   }
 
   @Test
-  public void testRuleOffsetValue() throws Exception {
+  void ruleOffsetValue() throws Exception {
     final Field ruleTypesOffset = JavadocTokenTypes.class.getDeclaredField("RULE_TYPES_OFFSET");
     ruleTypesOffset.setAccessible(true);
     assertWithMessage(
--- a/src/test/java/com/puppycrawl/tools/checkstyle/api/LineColumnTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/api/LineColumnTest.java
@@ -25,16 +25,16 @@ import nl.jqno.equalsverifier.EqualsVerifier;
 import nl.jqno.equalsverifier.EqualsVerifierReport;
 import org.junit.jupiter.api.Test;
 
-public class LineColumnTest {
+final class LineColumnTest {
 
   @Test
-  public void testCompareToBothEqual() {
+  void compareToBothEqual() {
     final int actual = new LineColumn(0, 0).compareTo(new LineColumn(0, 0));
     assertWithMessage("Invalid LineColumn comparing result").that(actual).isEqualTo(0);
   }
 
   @Test
-  public void testCompareToFirstLarger() {
+  void compareToFirstLarger() {
     final LineColumn lineColumn = new LineColumn(0, 0);
 
     final int line1column0 = new LineColumn(1, 0).compareTo(lineColumn);
@@ -44,7 +44,7 @@ public class LineColumnTest {
   }
 
   @Test
-  public void testCompareToFirstSmaller() {
+  void compareToFirstSmaller() {
     final Comparable<LineColumn> lineColumn = new LineColumn(0, 0);
 
     final int line1Column0 = lineColumn.compareTo(new LineColumn(1, 0));
@@ -54,14 +54,14 @@ public class LineColumnTest {
   }
 
   @Test
-  public void testEqualsAndHashCode() {
+  void equalsAndHashCode() {
     final EqualsVerifierReport ev =
         EqualsVerifier.forClass(LineColumn.class).usingGetClass().report();
     assertWithMessage("Error: " + ev.getMessage()).that(ev.isSuccessful()).isTrue();
   }
 
   @Test
-  public void testGetters() {
+  void getters() {
     final LineColumn lineColumn = new LineColumn(2, 3);
 
     assertWithMessage("Invalid LineColumn comparison result")
--- a/src/test/java/com/puppycrawl/tools/checkstyle/api/ScopeTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/api/ScopeTest.java
@@ -25,20 +25,20 @@ import org.junit.jupiter.api.Test;
 import org.junitpioneer.jupiter.DefaultLocale;
 
 /** Test cases for {@link Scope} enumeration. */
-public class ScopeTest {
+final class ScopeTest {
 
   /* Additional test for jacoco, since valueOf()
    * is generated by javac and jacoco reports that
    * valueOf() is uncovered.
    */
   @Test
-  public void testScopeValueOf() {
+  void scopeValueOf() {
     final Scope scope = Scope.valueOf("PRIVATE");
     assertWithMessage("Invalid scope").that(scope).isEqualTo(Scope.PRIVATE);
   }
 
   @Test
-  public void testMisc() {
+  void misc() {
     final Scope scope = Scope.getInstance("public");
     assertWithMessage("Scope must not be null").that(scope).isNotNull();
     assertWithMessage("Invalid scope toString").that(scope.toString()).isEqualTo("public");
@@ -55,7 +55,7 @@ public class ScopeTest {
   }
 
   @Test
-  public void testMixedCaseSpaces() {
+  void mixedCaseSpaces() {
     assertWithMessage("Invalid scope").that(Scope.getInstance("NothinG ")).isEqualTo(Scope.NOTHING);
     assertWithMessage("Invalid scope").that(Scope.getInstance(" PuBlic")).isEqualTo(Scope.PUBLIC);
     assertWithMessage("Invalid scope")
@@ -74,7 +74,7 @@ public class ScopeTest {
 
   @DefaultLocale(language = "tr", country = "TR")
   @Test
-  public void testMixedCaseSpacesWithDifferentLocale() {
+  void mixedCaseSpacesWithDifferentLocale() {
     assertWithMessage("Invalid scope").that(Scope.getInstance("NothinG ")).isEqualTo(Scope.NOTHING);
     assertWithMessage("Invalid scope").that(Scope.getInstance(" PuBlic")).isEqualTo(Scope.PUBLIC);
     assertWithMessage("Invalid scope")
@@ -92,7 +92,7 @@ public class ScopeTest {
   }
 
   @Test
-  public void testIsInAnonInner() {
+  void isInAnonInner() {
     assertWithMessage("Invalid subscope").that(Scope.NOTHING.isIn(Scope.ANONINNER)).isTrue();
     assertWithMessage("Invalid subscope").that(Scope.PUBLIC.isIn(Scope.ANONINNER)).isTrue();
     assertWithMessage("Invalid subscope").that(Scope.PROTECTED.isIn(Scope.ANONINNER)).isTrue();
@@ -102,7 +102,7 @@ public class ScopeTest {
   }
 
   @Test
-  public void testIsInPrivate() {
+  void isInPrivate() {
     assertWithMessage("Invalid subscope").that(Scope.NOTHING.isIn(Scope.PRIVATE)).isTrue();
     assertWithMessage("Invalid subscope").that(Scope.PUBLIC.isIn(Scope.PRIVATE)).isTrue();
     assertWithMessage("Invalid subscope").that(Scope.PROTECTED.isIn(Scope.PRIVATE)).isTrue();
@@ -112,7 +112,7 @@ public class ScopeTest {
   }
 
   @Test
-  public void testIsInPackage() {
+  void isInPackage() {
     assertWithMessage("Invalid subscope").that(Scope.NOTHING.isIn(Scope.PACKAGE)).isTrue();
     assertWithMessage("Invalid subscope").that(Scope.PUBLIC.isIn(Scope.PACKAGE)).isTrue();
     assertWithMessage("Invalid subscope").that(Scope.PROTECTED.isIn(Scope.PACKAGE)).isTrue();
@@ -122,7 +122,7 @@ public class ScopeTest {
   }
 
   @Test
-  public void testIsInProtected() {
+  void isInProtected() {
     assertWithMessage("Invalid subscope").that(Scope.NOTHING.isIn(Scope.PROTECTED)).isTrue();
     assertWithMessage("Invalid subscope").that(Scope.PUBLIC.isIn(Scope.PROTECTED)).isTrue();
     assertWithMessage("Invalid subscope").that(Scope.PROTECTED.isIn(Scope.PROTECTED)).isTrue();
@@ -132,7 +132,7 @@ public class ScopeTest {
   }
 
   @Test
-  public void testIsInPublic() {
+  void isInPublic() {
     assertWithMessage("Invalid subscope").that(Scope.NOTHING.isIn(Scope.PUBLIC)).isTrue();
     assertWithMessage("Invalid subscope").that(Scope.PUBLIC.isIn(Scope.PUBLIC)).isTrue();
     assertWithMessage("Invalid subscope").that(Scope.PROTECTED.isIn(Scope.PUBLIC)).isFalse();
@@ -142,7 +142,7 @@ public class ScopeTest {
   }
 
   @Test
-  public void testIsInNothing() {
+  void isInNothing() {
     assertWithMessage("Invalid subscope").that(Scope.NOTHING.isIn(Scope.NOTHING)).isTrue();
     assertWithMessage("Invalid subscope").that(Scope.PUBLIC.isIn(Scope.NOTHING)).isFalse();
     assertWithMessage("Invalid subscope").that(Scope.PROTECTED.isIn(Scope.NOTHING)).isFalse();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/api/SeverityLevelCounterTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/api/SeverityLevelCounterTest.java
@@ -23,10 +23,10 @@ import static com.google.common.truth.Truth.assertWithMessage;
 
 import org.junit.jupiter.api.Test;
 
-public class SeverityLevelCounterTest {
+final class SeverityLevelCounterTest {
 
   @Test
-  public void testCtorException() {
+  void ctorException() {
     try {
       final Object test = new SeverityLevelCounter(null);
       assertWithMessage("exception expected but got %s", test).fail();
@@ -39,7 +39,7 @@ public class SeverityLevelCounterTest {
   }
 
   @Test
-  public void testAddError() {
+  void addError() {
     final SeverityLevelCounter counter = new SeverityLevelCounter(SeverityLevel.ERROR);
     assertWithMessage("Invalid severity level count").that(counter.getCount()).isEqualTo(0);
     // not counted
@@ -59,7 +59,7 @@ public class SeverityLevelCounterTest {
   }
 
   @Test
-  public void testAddException() {
+  void addException() {
     final SeverityLevelCounter counter = new SeverityLevelCounter(SeverityLevel.ERROR);
     final AuditEvent event = new AuditEvent(this, "ATest.java", null);
     assertWithMessage("Invalid severity level count").that(counter.getCount()).isEqualTo(0);
@@ -68,7 +68,7 @@ public class SeverityLevelCounterTest {
   }
 
   @Test
-  public void testAddExceptionWarning() {
+  void addExceptionWarning() {
     final SeverityLevelCounter counter = new SeverityLevelCounter(SeverityLevel.WARNING);
     final AuditEvent event = new AuditEvent(this, "ATest.java", null);
     assertWithMessage("Invalid severity level count").that(counter.getCount()).isEqualTo(0);
@@ -77,7 +77,7 @@ public class SeverityLevelCounterTest {
   }
 
   @Test
-  public void testAuditStartedClearsState() {
+  void auditStartedClearsState() {
     final SeverityLevelCounter counter = new SeverityLevelCounter(SeverityLevel.ERROR);
     final AuditEvent event = new AuditEvent(this, "ATest.java", null);
     final AuditEvent secondEvent = new AuditEvent(this, "BTest.java", null);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/api/SeverityLevelTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/api/SeverityLevelTest.java
@@ -25,20 +25,20 @@ import org.junit.jupiter.api.Test;
 import org.junitpioneer.jupiter.DefaultLocale;
 
 /** Test cases for {@link SeverityLevel} enumeration. */
-public class SeverityLevelTest {
+final class SeverityLevelTest {
 
   /* Additional test for jacoco, since valueOf()
    * is generated by javac and jacoco reports that
    * valueOf() is uncovered.
    */
   @Test
-  public void testSeverityLevelValueOf() {
+  void severityLevelValueOf() {
     final SeverityLevel level = SeverityLevel.valueOf("INFO");
     assertWithMessage("Invalid severity level").that(level).isEqualTo(SeverityLevel.INFO);
   }
 
   @Test
-  public void testMisc() {
+  void misc() {
     final SeverityLevel severityLevel = SeverityLevel.getInstance("info");
     assertWithMessage("Invalid getInstance result, should not be null")
         .that(severityLevel)
@@ -60,7 +60,7 @@ public class SeverityLevelTest {
   }
 
   @Test
-  public void testMixedCaseSpaces() {
+  void mixedCaseSpaces() {
     assertWithMessage("Invalid getInstance result")
         .that(SeverityLevel.getInstance("IgnoRe "))
         .isEqualTo(SeverityLevel.IGNORE);
@@ -77,7 +77,7 @@ public class SeverityLevelTest {
 
   @DefaultLocale(language = "tr", country = "TR")
   @Test
-  public void testMixedCaseSpacesWithDifferentLocales() {
+  void mixedCaseSpacesWithDifferentLocales() {
     assertWithMessage("Invalid getInstance result")
         .that(SeverityLevel.getInstance("IgnoRe "))
         .isEqualTo(SeverityLevel.IGNORE);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/api/TokenTypesTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/api/TokenTypesTest.java
@@ -21,20 +21,20 @@ package com.puppycrawl.tools.checkstyle.api;
 
 import static com.google.common.truth.Truth.assertWithMessage;
 import static com.puppycrawl.tools.checkstyle.internal.utils.TestUtil.isUtilsClassHasPrivateConstructor;
+import static java.util.stream.Collectors.toUnmodifiableSet;
 
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.Locale;
 import java.util.ResourceBundle;
 import java.util.Set;
-import java.util.stream.Collectors;
 import org.junit.jupiter.api.Test;
 
-public class TokenTypesTest {
+final class TokenTypesTest {
 
   @Test
-  public void testAllTokenTypesHasDescription() {
+  void allTokenTypesHasDescription() {
     final String tokenTypes = "com.puppycrawl.tools.checkstyle.api.tokentypes";
     final ResourceBundle bundle = ResourceBundle.getBundle(tokenTypes, Locale.ROOT);
 
@@ -42,27 +42,27 @@ public class TokenTypesTest {
         Arrays.stream(TokenUtil.getAllTokenIds())
             .mapToObj(TokenUtil::getTokenName)
             .filter(name -> name.charAt(0) != '$')
-            .collect(Collectors.toUnmodifiableSet());
+            .collect(toUnmodifiableSet());
     final Set<String> actual = bundle.keySet();
     assertWithMessage("TokenTypes without description").that(actual).isEqualTo(expected);
   }
 
   @Test
-  public void testAllDescriptionsEndsWithPeriod() {
+  void allDescriptionsEndsWithPeriod() {
     final Set<String> badDescriptions =
         Arrays.stream(TokenUtil.getAllTokenIds())
             .mapToObj(TokenUtil::getTokenName)
             .filter(name -> name.charAt(0) != '$')
             .map(TokenUtil::getShortDescription)
             .filter(desc -> desc.charAt(desc.length() - 1) != '.')
-            .collect(Collectors.toUnmodifiableSet());
+            .collect(toUnmodifiableSet());
     assertWithMessage("Malformed TokenType descriptions")
         .that(badDescriptions)
-        .isEqualTo(Collections.emptySet());
+        .isEqualTo(ImmutableSet.of());
   }
 
   @Test
-  public void testGetShortDescription() {
+  void getShortDescription() {
     assertWithMessage("short description for EQUAL")
         .that(TokenUtil.getShortDescription("EQUAL"))
         .isEqualTo("The <code>==</code> (equal) operator.");
@@ -89,7 +89,7 @@ public class TokenTypesTest {
   }
 
   @Test
-  public void testIsProperUtilsClass() throws ReflectiveOperationException {
+  void isProperUtilsClass() throws ReflectiveOperationException {
     assertWithMessage("Constructor is not private")
         .that(isUtilsClassHasPrivateConstructor(TokenTypes.class))
         .isTrue();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/api/ViolationTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/api/ViolationTest.java
@@ -29,17 +29,17 @@ import nl.jqno.equalsverifier.EqualsVerifierReport;
 import org.junit.jupiter.api.Test;
 import org.junitpioneer.jupiter.DefaultLocale;
 
-public class ViolationTest {
+final class ViolationTest {
 
   @Test
-  public void testEqualsAndHashCode() {
+  void equalsAndHashCode() {
     final EqualsVerifierReport ev =
         EqualsVerifier.forClass(Violation.class).usingGetClass().report();
     assertWithMessage("Error: " + ev.getMessage()).that(ev.isSuccessful()).isTrue();
   }
 
   @Test
-  public void testGetSeverityLevel() {
+  void getSeverityLevel() {
     final Violation violation = createSampleViolation();
 
     assertWithMessage("Invalid severity level")
@@ -48,14 +48,14 @@ public class ViolationTest {
   }
 
   @Test
-  public void testGetModuleId() {
+  void getModuleId() {
     final Violation violation = createSampleViolation();
 
     assertWithMessage("Invalid module id").that(violation.getModuleId()).isEqualTo("module");
   }
 
   @Test
-  public void testGetSourceName() {
+  void getSourceName() {
     final Violation violation = createSampleViolation();
 
     assertWithMessage("Invalid source name")
@@ -65,7 +65,7 @@ public class ViolationTest {
 
   @DefaultLocale("en")
   @Test
-  public void testMessageInEnglish() {
+  void messageInEnglish() {
     final Violation violation = createSampleViolation();
 
     assertWithMessage("Invalid violation")
@@ -75,7 +75,7 @@ public class ViolationTest {
 
   @DefaultLocale("fr")
   @Test
-  public void testGetKey() {
+  void getKey() {
     final Violation violation = createSampleViolation();
 
     assertWithMessage("Invalid violation key")
@@ -84,7 +84,7 @@ public class ViolationTest {
   }
 
   @Test
-  public void testTokenType() {
+  void tokenType() {
     final Violation violation1 =
         new Violation(
             1,
@@ -119,7 +119,7 @@ public class ViolationTest {
   }
 
   @Test
-  public void testGetColumnCharIndex() {
+  void getColumnCharIndex() {
     final Violation violation1 =
         new Violation(
             1,
@@ -140,7 +140,7 @@ public class ViolationTest {
   }
 
   @Test
-  public void testCompareToWithDifferentModuleId() {
+  void compareToWithDifferentModuleId() {
     final Violation message1 = createSampleViolationWithId("module1");
     final Violation message2 = createSampleViolationWithId("module2");
     final Violation messageNull = createSampleViolationWithId(null);
@@ -155,7 +155,7 @@ public class ViolationTest {
   }
 
   @Test
-  public void testCompareToWithDifferentClass() {
+  void compareToWithDifferentClass() {
     final Violation message1 = createSampleViolationWithClass(AnnotationLocationCheck.class);
     final Violation message2 = createSampleViolationWithClass(AnnotationOnSameLineCheck.class);
     final Violation messageNull = createSampleViolationWithClass(null);
@@ -170,7 +170,7 @@ public class ViolationTest {
   }
 
   @Test
-  public void testCompareToWithDifferentLines() {
+  void compareToWithDifferentLines() {
     final Violation message1 = createSampleViolationWithLine(1);
     final Violation message1a = createSampleViolationWithLine(1);
     final Violation message2 = createSampleViolationWithLine(2);
@@ -182,7 +182,7 @@ public class ViolationTest {
   }
 
   @Test
-  public void testCompareToWithDifferentColumns() {
+  void compareToWithDifferentColumns() {
     final Violation message1 = createSampleViolationWithColumn(1);
     final Violation message1a = createSampleViolationWithColumn(1);
     final Violation message2 = createSampleViolationWithColumn(2);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/bdd/InlineConfigParser.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/bdd/InlineConfigParser.java
@@ -19,6 +19,8 @@
 
 package com.puppycrawl.tools.checkstyle.bdd;
 
+import static java.util.stream.Collectors.toUnmodifiableList;
+
 import com.puppycrawl.tools.checkstyle.ConfigurationLoader;
 import com.puppycrawl.tools.checkstyle.PropertiesExpander;
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
@@ -41,7 +43,6 @@ import java.util.Properties;
 import java.util.Set;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 import org.xml.sax.InputSource;
 
 public final class InlineConfigParser {
@@ -241,7 +242,7 @@ public final class InlineConfigParser {
     return lines.stream()
         .skip(1)
         .takeWhile(line -> !line.startsWith("*/"))
-        .collect(Collectors.toUnmodifiableList());
+        .collect(toUnmodifiableList());
   }
 
   private static void handleXmlConfig(
--- a/src/test/java/com/puppycrawl/tools/checkstyle/bdd/ModuleInputConfiguration.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/bdd/ModuleInputConfiguration.java
@@ -19,8 +19,9 @@
 
 package com.puppycrawl.tools.checkstyle.bdd;
 
+import static java.util.Collections.unmodifiableMap;
+
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -57,19 +58,19 @@ public final class ModuleInputConfiguration {
     final Map<String, String> properties = new HashMap<>();
     properties.putAll(defaultProperties);
     properties.putAll(nonDefaultProperties);
-    return Collections.unmodifiableMap(properties);
+    return unmodifiableMap(properties);
   }
 
   public Map<String, String> getDefaultProperties() {
-    return Collections.unmodifiableMap(defaultProperties);
+    return unmodifiableMap(defaultProperties);
   }
 
   public Map<String, String> getNonDefaultProperties() {
-    return Collections.unmodifiableMap(nonDefaultProperties);
+    return unmodifiableMap(nonDefaultProperties);
   }
 
   public Map<String, String> getModuleMessages() {
-    return Collections.unmodifiableMap(moduleMessages);
+    return unmodifiableMap(moduleMessages);
   }
 
   public DefaultConfiguration createConfiguration() {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/bdd/TestInputConfiguration.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/bdd/TestInputConfiguration.java
@@ -19,13 +19,14 @@
 
 package com.puppycrawl.tools.checkstyle.bdd;
 
+import static java.util.Collections.unmodifiableList;
+
 import com.puppycrawl.tools.checkstyle.Checker;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.TreeWalker;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
@@ -75,15 +76,15 @@ public final class TestInputConfiguration {
   }
 
   public List<ModuleInputConfiguration> getChildrenModules() {
-    return Collections.unmodifiableList(childrenModules);
+    return unmodifiableList(childrenModules);
   }
 
   public List<TestInputViolation> getViolations() {
-    return Collections.unmodifiableList(violations);
+    return unmodifiableList(violations);
   }
 
   public List<TestInputViolation> getFilteredViolations() {
-    return Collections.unmodifiableList(filteredViolations);
+    return unmodifiableList(filteredViolations);
   }
 
   public DefaultConfiguration createConfiguration() {
@@ -162,7 +163,7 @@ public final class TestInputConfiguration {
     }
 
     public List<ModuleInputConfiguration> getChildrenModules() {
-      return Collections.unmodifiableList(childrenModules);
+      return unmodifiableList(childrenModules);
     }
   }
 }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/ArrayTypeStyleCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/ArrayTypeStyleCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class ArrayTypeStyleCheckTest extends AbstractModuleTestSupport {
+final class ArrayTypeStyleCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class ArrayTypeStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final ArrayTypeStyleCheck checkObj = new ArrayTypeStyleCheck();
     final int[] expected = {TokenTypes.ARRAY_DECLARATOR};
     assertWithMessage("Required tokens differs from expected")
@@ -43,7 +43,7 @@ public class ArrayTypeStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavaStyleOn() throws Exception {
+  void javaStyleOn() throws Exception {
     final String[] expected = {
       "13:23: " + getCheckMessage(MSG_KEY),
       "14:18: " + getCheckMessage(MSG_KEY),
@@ -58,7 +58,7 @@ public class ArrayTypeStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavaStyleOff() throws Exception {
+  void javaStyleOff() throws Exception {
     final String[] expected = {
       "12:16: " + getCheckMessage(MSG_KEY),
       "16:39: " + getCheckMessage(MSG_KEY),
@@ -74,7 +74,7 @@ public class ArrayTypeStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNestedGenerics() throws Exception {
+  void nestedGenerics() throws Exception {
     final String[] expected = {
       "22:45: " + getCheckMessage(MSG_KEY),
       "23:61: " + getCheckMessage(MSG_KEY),
@@ -85,7 +85,7 @@ public class ArrayTypeStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final int[] expected = {TokenTypes.ARRAY_DECLARATOR};
     final ArrayTypeStyleCheck check = new ArrayTypeStyleCheck();
     final int[] actual = check.getAcceptableTokens();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/AvoidEscapedUnicodeCharactersCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/AvoidEscapedUnicodeCharactersCheckTest.java
@@ -31,7 +31,7 @@ import java.util.regex.Pattern;
 import java.util.stream.IntStream;
 import org.junit.jupiter.api.Test;
 
-public class AvoidEscapedUnicodeCharactersCheckTest extends AbstractModuleTestSupport {
+final class AvoidEscapedUnicodeCharactersCheckTest extends AbstractModuleTestSupport {
 
   // C0 (ASCII and derivatives)
   // https://en.wiktionary.org/wiki/Appendix:Control_characters#C0_.28ASCII_and_derivatives.29
@@ -63,7 +63,7 @@ public class AvoidEscapedUnicodeCharactersCheckTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final AvoidEscapedUnicodeCharactersCheck checkObj = new AvoidEscapedUnicodeCharactersCheck();
     final int[] expected = {
       TokenTypes.STRING_LITERAL, TokenTypes.CHAR_LITERAL, TokenTypes.TEXT_BLOCK_CONTENT,
@@ -74,7 +74,7 @@ public class AvoidEscapedUnicodeCharactersCheckTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "17:38: " + getCheckMessage(MSG_KEY),
       "19:38: " + getCheckMessage(MSG_KEY),
@@ -130,7 +130,7 @@ public class AvoidEscapedUnicodeCharactersCheckTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testAllowEscapesForControlCharacterSet() throws Exception {
+  void allowEscapesForControlCharacterSet() throws Exception {
     final String[] expected = {
       "17:38: " + getCheckMessage(MSG_KEY),
       "19:38: " + getCheckMessage(MSG_KEY),
@@ -181,7 +181,7 @@ public class AvoidEscapedUnicodeCharactersCheckTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testAllowByTailComment() throws Exception {
+  void allowByTailComment() throws Exception {
     final String[] expected = {
       "17:38: " + getCheckMessage(MSG_KEY),
       "25:38: " + getCheckMessage(MSG_KEY),
@@ -216,7 +216,7 @@ public class AvoidEscapedUnicodeCharactersCheckTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testAllowAllCharactersEscaped() throws Exception {
+  void allowAllCharactersEscaped() throws Exception {
     final String[] expected = {
       "17:38: " + getCheckMessage(MSG_KEY),
       "19:38: " + getCheckMessage(MSG_KEY),
@@ -249,7 +249,7 @@ public class AvoidEscapedUnicodeCharactersCheckTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void allowNonPrintableEscapes() throws Exception {
+  void allowNonPrintableEscapes() throws Exception {
     final String[] expected = {
       "17:38: " + getCheckMessage(MSG_KEY),
       "19:38: " + getCheckMessage(MSG_KEY),
@@ -288,7 +288,7 @@ public class AvoidEscapedUnicodeCharactersCheckTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testAllowByTailCommentWithEmoji() throws Exception {
+  void allowByTailCommentWithEmoji() throws Exception {
     final String[] expected = {
       "15:24: " + getCheckMessage(MSG_KEY),
       "18:24: " + getCheckMessage(MSG_KEY),
@@ -302,7 +302,7 @@ public class AvoidEscapedUnicodeCharactersCheckTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testAvoidEscapedUnicodeCharactersTextBlocksAllowByComment() throws Exception {
+  void avoidEscapedUnicodeCharactersTextBlocksAllowByComment() throws Exception {
     final String[] expected = {
       "18:30: " + getCheckMessage(MSG_KEY),
       "20:30: " + getCheckMessage(MSG_KEY),
@@ -319,7 +319,7 @@ public class AvoidEscapedUnicodeCharactersCheckTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testAvoidEscapedUnicodeCharactersTextBlocks() throws Exception {
+  void avoidEscapedUnicodeCharactersTextBlocks() throws Exception {
     final String[] expected = {
       "17:30: " + getCheckMessage(MSG_KEY),
       "18:30: " + getCheckMessage(MSG_KEY),
@@ -335,7 +335,7 @@ public class AvoidEscapedUnicodeCharactersCheckTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testAvoidEscapedUnicodeCharactersEscapedS() throws Exception {
+  void avoidEscapedUnicodeCharactersEscapedS() throws Exception {
     final String[] expected = {
       "17:21: " + getCheckMessage(MSG_KEY),
       "18:22: " + getCheckMessage(MSG_KEY),
@@ -349,7 +349,7 @@ public class AvoidEscapedUnicodeCharactersCheckTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final AvoidEscapedUnicodeCharactersCheck check = new AvoidEscapedUnicodeCharactersCheck();
     final int[] actual = check.getAcceptableTokens();
     final int[] expected = {
@@ -359,7 +359,7 @@ public class AvoidEscapedUnicodeCharactersCheckTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testAllowEscapesForControlCharacterSetForAllCharacters() throws Exception {
+  void allowEscapesForControlCharacterSetForAllCharacters() throws Exception {
 
     final int indexOfStartLineInInputFile = 16;
     final String message = getCheckMessage(MSG_KEY);
@@ -383,7 +383,7 @@ public class AvoidEscapedUnicodeCharactersCheckTest extends AbstractModuleTestSu
    * @throws Exception when code tested throws some exception
    */
   @Test
-  public void testCountMatches() throws Exception {
+  void countMatches() throws Exception {
     final AvoidEscapedUnicodeCharactersCheck check = new AvoidEscapedUnicodeCharactersCheck();
     final int actual =
         TestUtil.invokeMethod(
@@ -396,7 +396,7 @@ public class AvoidEscapedUnicodeCharactersCheckTest extends AbstractModuleTestSu
    * convenient for the sake of maintainability.
    */
   @Test
-  public void testNonPrintableCharsAreSorted() {
+  void nonPrintableCharsAreSorted() {
     String expression =
         TestUtil.<Pattern>getInternalStaticState(
                 AvoidEscapedUnicodeCharactersCheck.class, "NON_PRINTABLE_CHARS")
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/DescendantTokenCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/DescendantTokenCheckTest.java
@@ -28,7 +28,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class DescendantTokenCheckTest extends AbstractModuleTestSupport {
+final class DescendantTokenCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -36,13 +36,13 @@ public class DescendantTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputDescendantTokenIllegalTokens.java"), expected);
   }
 
   @Test
-  public void testMaximumNumber() throws Exception {
+  void maximumNumber() throws Exception {
     final String[] expected = {
       "32:12: " + getCheckMessage(MSG_KEY_MAX, 1, 0, "LITERAL_NATIVE", "LITERAL_NATIVE"),
     };
@@ -50,7 +50,7 @@ public class DescendantTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMessage() throws Exception {
+  void message() throws Exception {
     final String[] expected = {
       "32:12: Using 'native' is not allowed.",
     };
@@ -58,7 +58,7 @@ public class DescendantTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMinimumNumber() throws Exception {
+  void minimumNumber() throws Exception {
     final String[] expected = {
       "24:9: " + getCheckMessage(MSG_KEY_MIN, 1, 2, "LITERAL_SWITCH", "LITERAL_DEFAULT"),
     };
@@ -66,19 +66,19 @@ public class DescendantTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMinimumDepth() throws Exception {
+  void minimumDepth() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputDescendantTokenIllegalTokens5.java"), expected);
   }
 
   @Test
-  public void testMaximumDepth() throws Exception {
+  void maximumDepth() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputDescendantTokenIllegalTokens6.java"), expected);
   }
 
   @Test
-  public void testEmptyStatements() throws Exception {
+  void emptyStatements() throws Exception {
 
     final String[] expected = {
       "22:7: Empty statement.",
@@ -103,7 +103,7 @@ public class DescendantTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMissingSwitchDefault() throws Exception {
+  void missingSwitchDefault() throws Exception {
 
     final String[] expected = {
       "32:9: switch without \"default\" clause.",
@@ -114,7 +114,7 @@ public class DescendantTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStringLiteralEquality() throws Exception {
+  void stringLiteralEquality() throws Exception {
     final String[] expected = {
       "22:18: Literal Strings should be compared using equals(), not '=='.",
       "27:20: Literal Strings should be compared using equals(), not '=='.",
@@ -125,7 +125,7 @@ public class DescendantTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalTokenDefault() throws Exception {
+  void illegalTokenDefault() throws Exception {
 
     final String[] expected = {
       "23:9: Using 'LITERAL_SWITCH' is not allowed.",
@@ -136,7 +136,7 @@ public class DescendantTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalTokenNative() throws Exception {
+  void illegalTokenNative() throws Exception {
 
     final String[] expected = {
       "32:12: Using 'LITERAL_NATIVE' is not allowed.",
@@ -145,7 +145,7 @@ public class DescendantTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testReturnFromCatch() throws Exception {
+  void returnFromCatch() throws Exception {
 
     final String[] expected = {
       "22:11: Return from catch is not allowed.", "30:11: Return from catch is not allowed.",
@@ -155,7 +155,7 @@ public class DescendantTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testReturnFromFinally() throws Exception {
+  void returnFromFinally() throws Exception {
 
     final String[] expected = {
       "22:11: Return from finally is not allowed.", "30:11: Return from finally is not allowed.",
@@ -165,7 +165,7 @@ public class DescendantTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoSum() throws Exception {
+  void noSum() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -173,7 +173,7 @@ public class DescendantTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithSumCustomMsg() throws Exception {
+  void withSumCustomMsg() throws Exception {
 
     final String[] expected = {
       "37:32: this cannot be null.",
@@ -186,7 +186,7 @@ public class DescendantTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithSumDefaultMsg() throws Exception {
+  void withSumDefaultMsg() throws Exception {
 
     final String[] expected = {
       "37:32: " + getCheckMessage(MSG_KEY_SUM_MAX, 2, 1, "EQUAL"),
@@ -199,7 +199,7 @@ public class DescendantTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithSumLessThenMinDefMsg() throws Exception {
+  void withSumLessThenMinDefMsg() throws Exception {
 
     final String[] expected = {
       "32:44: " + getCheckMessage(MSG_KEY_SUM_MIN, 0, 3, "EQUAL"),
@@ -215,7 +215,7 @@ public class DescendantTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithSumLessThenMinCustomMsg() throws Exception {
+  void withSumLessThenMinCustomMsg() throws Exception {
 
     final String[] expected = {
       "31:44: custom message",
@@ -231,7 +231,7 @@ public class DescendantTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMaxTokenType() throws Exception {
+  void maxTokenType() throws Exception {
     final String[] expected = {
       "21:48: " + getCheckMessage(MSG_KEY_MAX, 1, 0, "OBJBLOCK", "LCURLY"),
       "21:48: " + getCheckMessage(MSG_KEY_MAX, 1, 0, "OBJBLOCK", "RCURLY"),
@@ -240,7 +240,7 @@ public class DescendantTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMaxTokenTypeReverseOrder() throws Exception {
+  void maxTokenTypeReverseOrder() throws Exception {
     final String[] expected = {
       "21:49: " + getCheckMessage(MSG_KEY_MAX, 1, 0, "OBJBLOCK", "LCURLY"),
       "21:49: " + getCheckMessage(MSG_KEY_MAX, 1, 0, "OBJBLOCK", "RCURLY"),
@@ -249,7 +249,7 @@ public class DescendantTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLimitedToken() throws Exception {
+  void limitedToken() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputDescendantTokenTestLimitedToken.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/FinalParametersCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/FinalParametersCheckTest.java
@@ -25,7 +25,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class FinalParametersCheckTest extends AbstractModuleTestSupport {
+final class FinalParametersCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class FinalParametersCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultTokens() throws Exception {
+  void defaultTokens() throws Exception {
     final String[] expected = {
       "27:26: " + getCheckMessage(MSG_KEY, "s"),
       "42:26: " + getCheckMessage(MSG_KEY, "i"),
@@ -51,7 +51,7 @@ public class FinalParametersCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCtorToken() throws Exception {
+  void ctorToken() throws Exception {
     final String[] expected = {
       "28:27: " + getCheckMessage(MSG_KEY, "s"),
       "43:27: " + getCheckMessage(MSG_KEY, "i"),
@@ -61,7 +61,7 @@ public class FinalParametersCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMethodToken() throws Exception {
+  void methodToken() throws Exception {
     final String[] expected = {
       "58:17: " + getCheckMessage(MSG_KEY, "s"),
       "74:17: " + getCheckMessage(MSG_KEY, "s"),
@@ -76,7 +76,7 @@ public class FinalParametersCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCatchToken() throws Exception {
+  void catchToken() throws Exception {
     final String[] expected = {
       "130:16: " + getCheckMessage(MSG_KEY, "npe"),
       "136:16: " + getCheckMessage(MSG_KEY, "e"),
@@ -86,7 +86,7 @@ public class FinalParametersCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testForEachClauseToken() throws Exception {
+  void forEachClauseToken() throws Exception {
     final String[] expected = {
       "157:13: " + getCheckMessage(MSG_KEY, "s"), "165:13: " + getCheckMessage(MSG_KEY, "s"),
     };
@@ -94,7 +94,7 @@ public class FinalParametersCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnorePrimitiveTypesParameters() throws Exception {
+  void ignorePrimitiveTypesParameters() throws Exception {
     final String[] expected = {
       "14:22: " + getCheckMessage(MSG_KEY, "k"),
       "15:15: " + getCheckMessage(MSG_KEY, "s"),
@@ -108,7 +108,7 @@ public class FinalParametersCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPrimitiveTypesParameters() throws Exception {
+  void primitiveTypesParameters() throws Exception {
     final String[] expected = {
       "13:14: " + getCheckMessage(MSG_KEY, "i"),
       "14:15: " + getCheckMessage(MSG_KEY, "i"),
@@ -129,7 +129,7 @@ public class FinalParametersCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testReceiverParameters() throws Exception {
+  void receiverParameters() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputFinalParametersReceiver.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/NewlineAtEndOfFileCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/NewlineAtEndOfFileCheckTest.java
@@ -40,7 +40,7 @@ import java.util.List;
 import java.util.Set;
 import org.junit.jupiter.api.Test;
 
-public class NewlineAtEndOfFileCheckTest extends AbstractModuleTestSupport {
+final class NewlineAtEndOfFileCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -48,13 +48,13 @@ public class NewlineAtEndOfFileCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNewlineLfAtEndOfFile() throws Exception {
+  void newlineLfAtEndOfFile() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputNewlineAtEndOfFileLf.java"), expected);
   }
 
   @Test
-  public void testNewlineLfAtEndOfFileLfNotOverlapWithCrLf() throws Exception {
+  void newlineLfAtEndOfFileLfNotOverlapWithCrLf() throws Exception {
     final String[] expected = {
       "1: " + getCheckMessage(MSG_KEY_WRONG_ENDING),
     };
@@ -62,19 +62,19 @@ public class NewlineAtEndOfFileCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNewlineCrlfAtEndOfFile() throws Exception {
+  void newlineCrlfAtEndOfFile() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputNewlineAtEndOfFileCrlf3.java"), expected);
   }
 
   @Test
-  public void testNewlineCrAtEndOfFile() throws Exception {
+  void newlineCrAtEndOfFile() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputNewlineAtEndOfFileCr.java"), expected);
   }
 
   @Test
-  public void testAnyNewlineAtEndOfFile() throws Exception {
+  void anyNewlineAtEndOfFile() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputNewlineAtEndOfFileCrlf2.java"), expected);
     verifyWithInlineConfigParser(getPath("InputNewlineAtEndOfFileLf2.java"), expected);
@@ -82,7 +82,7 @@ public class NewlineAtEndOfFileCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoNewlineLfAtEndOfFile() throws Exception {
+  void noNewlineLfAtEndOfFile() throws Exception {
     final String[] expected = {
       "1: " + getCheckMessage(MSG_KEY_NO_NEWLINE_EOF),
     };
@@ -90,7 +90,7 @@ public class NewlineAtEndOfFileCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoNewlineAtEndOfFile() throws Exception {
+  void noNewlineAtEndOfFile() throws Exception {
     final String msgKeyNoNewlineEof = "File does not end with a newline :)";
     final String[] expected = {
       "1: " + msgKeyNoNewlineEof,
@@ -99,7 +99,7 @@ public class NewlineAtEndOfFileCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSetLineSeparatorFailure() throws Exception {
+  void setLineSeparatorFailure() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(NewlineAtEndOfFileCheck.class);
     checkConfig.addProperty("lineSeparator", "ct");
     try {
@@ -116,7 +116,7 @@ public class NewlineAtEndOfFileCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyFileFile() throws Exception {
+  void emptyFileFile() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(NewlineAtEndOfFileCheck.class);
     checkConfig.addProperty("lineSeparator", LineSeparatorOption.LF.toString());
     final String[] expected = {
@@ -126,7 +126,7 @@ public class NewlineAtEndOfFileCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFileWithEmptyLineOnly() throws Exception {
+  void fileWithEmptyLineOnly() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(NewlineAtEndOfFileCheck.class);
     checkConfig.addProperty("lineSeparator", LineSeparatorOption.LF.toString());
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -134,7 +134,7 @@ public class NewlineAtEndOfFileCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFileWithEmptyLineOnlyWithLfCrCrlf() throws Exception {
+  void fileWithEmptyLineOnlyWithLfCrCrlf() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(NewlineAtEndOfFileCheck.class);
     checkConfig.addProperty("lineSeparator", LineSeparatorOption.LF_CR_CRLF.toString());
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -142,7 +142,7 @@ public class NewlineAtEndOfFileCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWrongFile() throws Exception {
+  void wrongFile() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(NewlineAtEndOfFileCheck.class);
     final NewlineAtEndOfFileCheck check = new NewlineAtEndOfFileCheck();
     check.configure(checkConfig);
@@ -159,7 +159,7 @@ public class NewlineAtEndOfFileCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWrongSeparatorLength() throws Exception {
+  void wrongSeparatorLength() throws Exception {
     try (RandomAccessFile file =
         new ReadZeroRandomAccessFile(getPath("InputNewlineAtEndOfFileLf.java"), "r")) {
       TestUtil.invokeMethod(
@@ -175,7 +175,7 @@ public class NewlineAtEndOfFileCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTrimOptionProperty() throws Exception {
+  void trimOptionProperty() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputNewlineAtEndOfFileTestTrimProperty.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/NoCodeInFileCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/NoCodeInFileCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class NoCodeInFileCheckTest extends AbstractModuleTestSupport {
+final class NoCodeInFileCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class NoCodeInFileCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final NoCodeInFileCheck checkObj = new NoCodeInFileCheck();
     assertWithMessage("Required tokens array is not empty")
         .that(checkObj.getRequiredTokens())
@@ -43,7 +43,7 @@ public class NoCodeInFileCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final NoCodeInFileCheck checkObj = new NoCodeInFileCheck();
     assertWithMessage("Acceptable tokens array is not empty")
         .that(checkObj.getAcceptableTokens())
@@ -51,7 +51,7 @@ public class NoCodeInFileCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBlank() throws Exception {
+  void blank() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(NoCodeInFileCheck.class);
     final String[] expected = {
       "1: " + getCheckMessage(MSG_KEY_NO_CODE),
@@ -60,7 +60,7 @@ public class NoCodeInFileCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSingleLineComment() throws Exception {
+  void singleLineComment() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(NoCodeInFileCheck.class);
     final String[] expected = {
       "1: " + getCheckMessage(MSG_KEY_NO_CODE),
@@ -69,7 +69,7 @@ public class NoCodeInFileCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMultiLineComment() throws Exception {
+  void multiLineComment() throws Exception {
     final String[] expected = {
       "1: " + getCheckMessage(MSG_KEY_NO_CODE),
     };
@@ -77,12 +77,12 @@ public class NoCodeInFileCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFileContainingCode() throws Exception {
+  void fileContainingCode() throws Exception {
     verifyWithInlineConfigParser(getPath("InputNoCodeInFile4.java"), CommonUtil.EMPTY_STRING_ARRAY);
   }
 
   @Test
-  public void testBothSingleLineAndMultiLineComment() throws Exception {
+  void bothSingleLineAndMultiLineComment() throws Exception {
     final String[] expected = {
       "1: " + getCheckMessage(MSG_KEY_NO_CODE),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/OrderedPropertiesCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/OrderedPropertiesCheckTest.java
@@ -23,6 +23,7 @@ import static com.google.common.truth.Truth.assertWithMessage;
 import static com.puppycrawl.tools.checkstyle.checks.OrderedPropertiesCheck.MSG_IO_EXCEPTION_KEY;
 import static com.puppycrawl.tools.checkstyle.checks.OrderedPropertiesCheck.MSG_KEY;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.api.FileText;
@@ -33,11 +34,10 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.nio.file.Files;
 import java.nio.file.NoSuchFileException;
-import java.util.Collections;
 import java.util.SortedSet;
 import org.junit.jupiter.api.Test;
 
-public class OrderedPropertiesCheckTest extends AbstractModuleTestSupport {
+final class OrderedPropertiesCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -46,7 +46,7 @@ public class OrderedPropertiesCheckTest extends AbstractModuleTestSupport {
 
   /** Tests the ordinal work of a check. Test of sub keys, repeating key pairs in wrong order */
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(OrderedPropertiesCheck.class);
     final String[] expected = {
       "8: " + getCheckMessage(MSG_KEY, "key1", "key2"),
@@ -58,7 +58,7 @@ public class OrderedPropertiesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testKeysOnly() throws Exception {
+  void keysOnly() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(OrderedPropertiesCheck.class);
     final String[] expected = {
       "3: " + getCheckMessage(MSG_KEY, "key1", "key2"),
@@ -67,7 +67,7 @@ public class OrderedPropertiesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyKeys() throws Exception {
+  void emptyKeys() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(OrderedPropertiesCheck.class);
     final String[] expected = {
       "3: " + getCheckMessage(MSG_KEY, "key11", "key2"),
@@ -76,7 +76,7 @@ public class OrderedPropertiesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMalformedValue() throws Exception {
+  void malformedValue() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(OrderedPropertiesCheck.class);
     final String fileName = getPath("InputOrderedProperties3MalformedValue.properties");
 
@@ -87,7 +87,7 @@ public class OrderedPropertiesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommentsMultiLine() throws Exception {
+  void commentsMultiLine() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(OrderedPropertiesCheck.class);
     final String[] expected = {
       "5: " + getCheckMessage(MSG_KEY, "aKey", "multi.line"),
@@ -96,7 +96,7 @@ public class OrderedPropertiesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLineNumberRepeatingPreviousKey() throws Exception {
+  void lineNumberRepeatingPreviousKey() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(OrderedPropertiesCheck.class);
     final String[] expected = {
       "3: " + getCheckMessage(MSG_KEY, "a", "b"),
@@ -106,7 +106,7 @@ public class OrderedPropertiesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testShouldNotProcessFilesWithWrongFileExtension() throws Exception {
+  void shouldNotProcessFilesWithWrongFileExtension() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(OrderedPropertiesCheck.class);
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verify(checkConfig, getPath("InputOrderedProperties.txt"), expected);
@@ -114,13 +114,13 @@ public class OrderedPropertiesCheckTest extends AbstractModuleTestSupport {
 
   /** Tests IO exception, that can occur during reading of properties file. */
   @Test
-  public void testIoException() throws Exception {
+  void ioException() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(OrderedPropertiesCheck.class);
     final OrderedPropertiesCheck check = new OrderedPropertiesCheck();
     check.configure(checkConfig);
     final String fileName = getPath("InputOrderedPropertiesCheckNotExisting.properties");
     final File file = new File(fileName);
-    final FileText fileText = new FileText(file, Collections.emptyList());
+    final FileText fileText = new FileText(file, ImmutableList.of());
     final SortedSet<Violation> violations = check.process(file, fileText);
     assertWithMessage("Wrong violations count").that(violations).hasSize(1);
     final Violation violation = violations.iterator().next();
@@ -140,21 +140,21 @@ public class OrderedPropertiesCheckTest extends AbstractModuleTestSupport {
    * returning zero size. This will keep the for loop intact.
    */
   @Test
-  public void testKeepForLoopIntact() throws Exception {
+  void keepForLoopIntact() throws Exception {
 
     final DefaultConfiguration checkConfig = createModuleConfig(OrderedPropertiesCheck.class);
     final OrderedPropertiesCheck check = new OrderedPropertiesCheck();
     check.configure(checkConfig);
     final String fileName = getPath("InputOrderedProperties2EmptyValue.properties");
     final File file = new File(fileName);
-    final FileText fileText = new FileText(file, Collections.emptyList());
+    final FileText fileText = new FileText(file, ImmutableList.of());
     final SortedSet<Violation> violations = check.process(file, fileText);
 
     assertWithMessage("Wrong violations count").that(violations).hasSize(1);
   }
 
   @Test
-  public void testFileExtension() {
+  void fileExtension() {
 
     final OrderedPropertiesCheck check = new OrderedPropertiesCheck();
     assertWithMessage("File extension should be set")
@@ -163,7 +163,7 @@ public class OrderedPropertiesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test() throws Exception {
+  void test() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(OrderedPropertiesCheck.class);
     final String[] expected = {
       "3: " + getCheckMessage(MSG_KEY, " A ", " B"),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/OuterTypeFilenameCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/OuterTypeFilenameCheckTest.java
@@ -22,6 +22,7 @@ package com.puppycrawl.tools.checkstyle.checks;
 import static com.google.common.truth.Truth.assertWithMessage;
 import static com.puppycrawl.tools.checkstyle.checks.OuterTypeFilenameCheck.MSG_KEY;
 
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
@@ -31,7 +32,7 @@ import java.io.File;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class OuterTypeFilenameCheckTest extends AbstractModuleTestSupport {
+final class OuterTypeFilenameCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -39,7 +40,7 @@ public class OuterTypeFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final OuterTypeFilenameCheck checkObj = new OuterTypeFilenameCheck();
     final int[] expected = {
       TokenTypes.CLASS_DEF,
@@ -54,19 +55,19 @@ public class OuterTypeFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGood1() throws Exception {
+  void good1() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputOuterTypeFilenameIllegalTokens.java"), expected);
   }
 
   @Test
-  public void testGood2() throws Exception {
+  void good2() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputOuterTypeFilename15Extensions.java"), expected);
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final OuterTypeFilenameCheck check = new OuterTypeFilenameCheck();
     final int[] actual = check.getAcceptableTokens();
     final int[] expected = {
@@ -82,13 +83,13 @@ public class OuterTypeFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNestedClass() throws Exception {
+  void nestedClass() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputOuterTypeFilename1.java"), expected);
   }
 
   @Test
-  public void testNestedClass2() throws Exception {
+  void nestedClass2() throws Exception {
     final String[] expected = {
       "9:1: " + getCheckMessage(MSG_KEY),
     };
@@ -96,19 +97,19 @@ public class OuterTypeFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFinePublic() throws Exception {
+  void finePublic() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputOuterTypeFilename2.java"), expected);
   }
 
   @Test
-  public void testPublicClassIsNotFirst() throws Exception {
+  void publicClassIsNotFirst() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputOuterTypeFilenameCheckPublic.java"), expected);
   }
 
   @Test
-  public void testNoPublicClasses() throws Exception {
+  void noPublicClasses() throws Exception {
     final String[] expected = {
       "9:1: " + getCheckMessage(MSG_KEY),
     };
@@ -116,13 +117,13 @@ public class OuterTypeFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFineDefault() throws Exception {
+  void fineDefault() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputOuterTypeFilename3.java"), expected);
   }
 
   @Test
-  public void testWrongDefault() throws Exception {
+  void wrongDefault() throws Exception {
     final String[] expected = {
       "10:2: " + getCheckMessage(MSG_KEY),
     };
@@ -130,7 +131,7 @@ public class OuterTypeFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackageAnnotation() throws Exception {
+  void packageAnnotation() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -138,7 +139,7 @@ public class OuterTypeFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOuterTypeFilenameRecords() throws Exception {
+  void outerTypeFilenameRecords() throws Exception {
 
     final String[] expected = {
       "10:1: " + getCheckMessage(MSG_KEY),
@@ -148,7 +149,7 @@ public class OuterTypeFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOuterTypeFilenameRecordsMethodRecordDef() throws Exception {
+  void outerTypeFilenameRecordsMethodRecordDef() throws Exception {
 
     final String[] expected = {
       "10:1: " + getCheckMessage(MSG_KEY),
@@ -158,7 +159,7 @@ public class OuterTypeFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStateIsClearedOnBeginTree2() throws Exception {
+  void stateIsClearedOnBeginTree2() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(OuterTypeFilenameCheck.class);
     final String file1 = getPath("InputOuterTypeFilenameBeginTree1.java");
     final String file2 = getPath("InputOuterTypeFilenameBeginTree2.java");
@@ -175,12 +176,12 @@ public class OuterTypeFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStateIsClearedOnBeginTree3() throws Exception {
+  void stateIsClearedOnBeginTree3() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(OuterTypeFilenameCheck.class);
     final String file1 = getPath("InputOuterTypeFilenameBeginTree1.java");
     final String file2 = getPath("InputOuterTypeFilename1a.java");
     final List<String> expectedFirstInput = List.of(CommonUtil.EMPTY_STRING_ARRAY);
-    final List<String> expectedSecondInput = List.of("9:1: " + getCheckMessage(MSG_KEY));
+    final List<String> expectedSecondInput = ImmutableList.of("9:1: " + getCheckMessage(MSG_KEY));
     final File[] inputs = {new File(file1), new File(file2)};
 
     verify(
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/SuppressWarningsHolderTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/SuppressWarningsHolderTest.java
@@ -48,7 +48,7 @@ import java.util.Optional;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Test;
 
-public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
+final class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -56,7 +56,7 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @AfterEach
-  public void cleanUp() {
+  void cleanUp() {
     // clear cache that may have been set by tests
 
     new SuppressWarningsHolder().beginTree(null);
@@ -67,7 +67,7 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGet() {
+  void get() {
     final SuppressWarningsHolder checkObj = new SuppressWarningsHolder();
     final int[] expected = {TokenTypes.ANNOTATION};
     assertWithMessage("Required token array differs from expected")
@@ -79,14 +79,14 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOnComplexAnnotations() throws Exception {
+  void onComplexAnnotations() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputSuppressWarningsHolder.java"), expected);
   }
 
   @Test
-  public void testOnComplexAnnotationsNonConstant() throws Exception {
+  void onComplexAnnotationsNonConstant() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -94,14 +94,14 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCustomAnnotation() throws Exception {
+  void customAnnotation() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputSuppressWarningsHolder5.java"), expected);
   }
 
   @Test
-  public void testAll() throws Exception {
+  void all() throws Exception {
     final String[] expected = {
       "21:23: "
           + getCheckMessage(
@@ -112,7 +112,7 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetDefaultAlias() {
+  void getDefaultAlias() {
     assertWithMessage("Default alias differs from expected")
         .that(SuppressWarningsHolder.getDefaultAlias("SomeName"))
         .isEqualTo("somename");
@@ -122,7 +122,7 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSetAliasListEmpty() {
+  void setAliasListEmpty() {
     final SuppressWarningsHolder holder = new SuppressWarningsHolder();
     holder.setAliasList("");
     assertWithMessage("Empty alias list should not be set")
@@ -131,7 +131,7 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSetAliasListCorrect() {
+  void setAliasListCorrect() {
     final SuppressWarningsHolder holder = new SuppressWarningsHolder();
     holder.setAliasList("alias=value");
     assertWithMessage("Alias differs from expected")
@@ -140,7 +140,7 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSetAliasListWrong() {
+  void setAliasListWrong() {
     final SuppressWarningsHolder holder = new SuppressWarningsHolder();
 
     try {
@@ -154,7 +154,7 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIsSuppressed() throws Exception {
+  void isSuppressed() throws Exception {
     populateHolder("MockEntry", 100, 100, 350, 350);
     final AuditEvent event = createAuditEvent("check", 100, 10);
 
@@ -164,7 +164,7 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIsSuppressedByName() throws Exception {
+  void isSuppressedByName() throws Exception {
     populateHolder("check", 100, 100, 350, 350);
     final SuppressWarningsHolder holder = new SuppressWarningsHolder();
     final AuditEvent event = createAuditEvent("id", 110, 10);
@@ -176,7 +176,7 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIsSuppressedByModuleId() throws Exception {
+  void isSuppressedByModuleId() throws Exception {
     populateHolder("check", 100, 100, 350, 350);
     final AuditEvent event = createAuditEvent("check", 350, 350);
 
@@ -186,7 +186,7 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIsSuppressedAfterEventEnd() throws Exception {
+  void isSuppressedAfterEventEnd() throws Exception {
     populateHolder("check", 100, 100, 350, 350);
     final AuditEvent event = createAuditEvent("check", 350, 352);
 
@@ -196,7 +196,7 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIsSuppressedAfterEventEnd2() throws Exception {
+  void isSuppressedAfterEventEnd2() throws Exception {
     populateHolder("check", 100, 100, 350, 350);
     final AuditEvent event = createAuditEvent("check", 400, 10);
 
@@ -206,7 +206,7 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIsSuppressedAfterEventStart() throws Exception {
+  void isSuppressedAfterEventStart() throws Exception {
     populateHolder("check", 100, 100, 350, 350);
     final AuditEvent event = createAuditEvent("check", 100, 100);
 
@@ -216,7 +216,7 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIsSuppressedAfterEventStart2() throws Exception {
+  void isSuppressedAfterEventStart2() throws Exception {
     populateHolder("check", 100, 100, 350, 350);
     final AuditEvent event = createAuditEvent("check", 100, 0);
 
@@ -226,7 +226,7 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIsSuppressedWithAllArgument() throws Exception {
+  void isSuppressedWithAllArgument() throws Exception {
     populateHolder("all", 100, 100, 350, 350);
 
     final Checker source = new Checker();
@@ -254,21 +254,21 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationInTry() throws Exception {
+  void annotationInTry() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputSuppressWarningsHolder2.java"), expected);
   }
 
   @Test
-  public void testEmptyAnnotation() throws Exception {
+  void emptyAnnotation() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputSuppressWarningsHolder3.java"), expected);
   }
 
   @Test
-  public void testGetAllAnnotationValuesWrongArg() throws ReflectiveOperationException {
+  void getAllAnnotationValuesWrongArg() throws ReflectiveOperationException {
     final SuppressWarningsHolder holder = new SuppressWarningsHolder();
     final Method getAllAnnotationValues =
         holder.getClass().getDeclaredMethod("getAllAnnotationValues", DetailAST.class);
@@ -304,7 +304,7 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAnnotationValuesWrongArg() throws ReflectiveOperationException {
+  void getAnnotationValuesWrongArg() throws ReflectiveOperationException {
     final SuppressWarningsHolder holder = new SuppressWarningsHolder();
     final Method getAllAnnotationValues =
         holder.getClass().getDeclaredMethod("getAnnotationValues", DetailAST.class);
@@ -334,7 +334,7 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAnnotationTargetWrongArg() throws ReflectiveOperationException {
+  void getAnnotationTargetWrongArg() throws ReflectiveOperationException {
     final SuppressWarningsHolder holder = new SuppressWarningsHolder();
     final Method getAnnotationTarget =
         holder.getClass().getDeclaredMethod("getAnnotationTarget", DetailAST.class);
@@ -368,7 +368,7 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAstWithoutChildren() {
+  void astWithoutChildren() {
     final SuppressWarningsHolder holder = new SuppressWarningsHolder();
     final DetailAstImpl methodDef = new DetailAstImpl();
     methodDef.setType(TokenTypes.METHOD_DEF);
@@ -384,22 +384,22 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationWithFullName() throws Exception {
+  void annotationWithFullName() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputSuppressWarningsHolder4.java"), expected);
   }
 
   @Test
-  public void testSuppressWarningsAsAnnotationProperty() throws Exception {
+  void suppressWarningsAsAnnotationProperty() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputSuppressWarningsHolder7.java"), expected);
   }
 
-  @Test
   @SuppressWarnings("unchecked")
-  public void testClearState() throws Exception {
+  @Test
+  void clearState() throws Exception {
     final SuppressWarningsHolder check = new SuppressWarningsHolder();
 
     final Optional<DetailAST> annotationDef =
@@ -414,7 +414,7 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
         .that(
             TestUtil.isStatefulFieldClearedDuringBeginTree(
                 check,
-                annotationDef.get(),
+                annotationDef.orElseThrow(),
                 "ENTRIES",
                 entries -> ((ThreadLocal<List<Object>>) entries).get().isEmpty()))
         .isTrue();
@@ -445,7 +445,7 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSuppressWarningsTextBlocks() throws Exception {
+  void suppressWarningsTextBlocks() throws Exception {
     final String pattern = "^[a-z][a-zA-Z0-9]*$";
 
     final String[] expected = {
@@ -465,7 +465,7 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithAndWithoutCheckSuffixDifferentCases() throws Exception {
+  void withAndWithoutCheckSuffixDifferentCases() throws Exception {
     final String pattern = "^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$";
     final String[] expected = {
       "16:30: "
@@ -479,7 +479,7 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAliasList() throws Exception {
+  void aliasList() throws Exception {
     final String[] expected = {
       "16:17: " + getCheckMessage(ParameterNumberCheck.class, ParameterNumberCheck.MSG_KEY, 7, 8),
       "28:17: " + getCheckMessage(ParameterNumberCheck.class, ParameterNumberCheck.MSG_KEY, 7, 8),
@@ -488,7 +488,7 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAliasList2() throws Exception {
+  void aliasList2() throws Exception {
     final String pattern = "^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$";
     final String[] expected = {
       "16:29: "
@@ -503,14 +503,14 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIdent() throws Exception {
+  void ident() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getNonCompilablePath("InputSuppressWarningsHolder1.java"), expected);
   }
 
   @Test
-  public void testIdent2() throws Exception {
+  void ident2() throws Exception {
     final String[] expected = {
       "37:9: " + getCheckMessage(UnusedLocalVariableCheck.class, MSG_UNUSED_LOCAL_VARIABLE, "a"),
       "42:9: " + getCheckMessage(UnusedLocalVariableCheck.class, MSG_UNUSED_LOCAL_VARIABLE, "a"),
@@ -520,7 +520,7 @@ public class SuppressWarningsHolderTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test3() throws Exception {
+  void test3() throws Exception {
     final String pattern = "^[a-z][a-zA-Z0-9]*$";
 
     final String[] expected = {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/TodoCommentCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/TodoCommentCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class TodoCommentCheckTest extends AbstractModuleTestSupport {
+final class TodoCommentCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class TodoCommentCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final TodoCommentCheck checkObj = new TodoCommentCheck();
     final int[] expected = {TokenTypes.COMMENT_CONTENT};
     assertWithMessage("Required tokens differs from expected")
@@ -43,7 +43,7 @@ public class TodoCommentCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIt() throws Exception {
+  void it() throws Exception {
     final String[] expected = {
       "1:3: " + getCheckMessage(MSG_KEY, "FIXME:"),
       "164:7: " + getCheckMessage(MSG_KEY, "FIXME:"),
@@ -54,7 +54,7 @@ public class TodoCommentCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final int[] expected = {TokenTypes.COMMENT_CONTENT};
     final TodoCommentCheck check = new TodoCommentCheck();
     final int[] actual = check.getAcceptableTokens();
@@ -65,7 +65,7 @@ public class TodoCommentCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test() throws Exception {
+  void test() throws Exception {
     final String[] expected = {
       "11:16: " + getCheckMessage(MSG_KEY, "TODO:"),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/TrailingCommentCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/TrailingCommentCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class TrailingCommentCheckTest extends AbstractModuleTestSupport {
+final class TrailingCommentCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class TrailingCommentCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final TrailingCommentCheck checkObj = new TrailingCommentCheck();
     final int[] expected = {
       TokenTypes.SINGLE_LINE_COMMENT, TokenTypes.BLOCK_COMMENT_BEGIN,
@@ -46,7 +46,7 @@ public class TrailingCommentCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final TrailingCommentCheck checkObj = new TrailingCommentCheck();
     final int[] expected = {
       TokenTypes.SINGLE_LINE_COMMENT, TokenTypes.BLOCK_COMMENT_BEGIN,
@@ -57,7 +57,7 @@ public class TrailingCommentCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaults() throws Exception {
+  void defaults() throws Exception {
     final String[] expected = {
       "13:12: " + getCheckMessage(MSG_KEY),
       "17:12: " + getCheckMessage(MSG_KEY),
@@ -72,7 +72,7 @@ public class TrailingCommentCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLegalComment() throws Exception {
+  void legalComment() throws Exception {
     final String[] expected = {
       "13:12: " + getCheckMessage(MSG_KEY),
       "17:12: " + getCheckMessage(MSG_KEY),
@@ -86,7 +86,7 @@ public class TrailingCommentCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFormat() throws Exception {
+  void format() throws Exception {
     final String[] expected = {
       "1:1: " + getCheckMessage(MSG_KEY),
       "12:12: " + getCheckMessage(MSG_KEY),
@@ -111,7 +111,7 @@ public class TrailingCommentCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLegalCommentWithNoPrecedingWhitespace() throws Exception {
+  void legalCommentWithNoPrecedingWhitespace() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -119,7 +119,7 @@ public class TrailingCommentCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithEmoji() throws Exception {
+  void withEmoji() throws Exception {
     final String[] expected = {
       "13:24: " + getCheckMessage(MSG_KEY),
       "15:27: " + getCheckMessage(MSG_KEY),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/TranslationCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/TranslationCheckTest.java
@@ -22,7 +22,9 @@ package com.puppycrawl.tools.checkstyle.checks;
 import static com.google.common.truth.Truth.assertWithMessage;
 import static com.puppycrawl.tools.checkstyle.checks.TranslationCheck.MSG_KEY;
 import static com.puppycrawl.tools.checkstyle.checks.TranslationCheck.MSG_KEY_MISSING_TRANSLATION_FILE;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.puppycrawl.tools.checkstyle.AbstractAutomaticBean.OutputStreamOptions;
 import com.puppycrawl.tools.checkstyle.AbstractXmlTestSupport;
@@ -44,7 +46,6 @@ import java.io.Writer;
 import java.lang.reflect.Field;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
-import java.util.Collections;
 import java.util.Set;
 import java.util.SortedSet;
 import java.util.TreeSet;
@@ -52,7 +53,7 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
 import org.w3c.dom.Node;
 
-public class TranslationCheckTest extends AbstractXmlTestSupport {
+final class TranslationCheckTest extends AbstractXmlTestSupport {
 
   @TempDir public File temporaryFolder;
 
@@ -62,7 +63,7 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testTranslation() throws Exception {
+  void translation() throws Exception {
     final Configuration checkConfig = createModuleConfig(TranslationCheck.class);
     final String[] expected = {
       "1: " + getCheckMessage(MSG_KEY, "only.english"),
@@ -79,7 +80,7 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testDifferentBases() throws Exception {
+  void differentBases() throws Exception {
     final Configuration checkConfig = createModuleConfig(TranslationCheck.class);
     final String[] expected = {
       "1: " + getCheckMessage(MSG_KEY, "only.english"),
@@ -98,9 +99,9 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testDifferentPaths() throws Exception {
+  void differentPaths() throws Exception {
     final File file = new File(temporaryFolder, "messages_test_de.properties");
-    try (Writer writer = Files.newBufferedWriter(file.toPath(), StandardCharsets.UTF_8)) {
+    try (Writer writer = Files.newBufferedWriter(file.toPath(), UTF_8)) {
       final String content = "hello=Hello\ncancel=Cancel";
       writer.write(content);
     }
@@ -122,7 +123,7 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
    * @throws Exception when code tested throws exception
    */
   @Test
-  public void testStateIsCleared() throws Exception {
+  void stateIsCleared() throws Exception {
     final File fileToProcess = new File(getPath("InputTranslationCheckFireErrors_de.properties"));
     final String charset = StandardCharsets.UTF_8.name();
     final TranslationCheck check = new TranslationCheck();
@@ -138,7 +139,7 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testFileExtension() throws Exception {
+  void fileExtension() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(TranslationCheck.class);
     checkConfig.addProperty("baseName", "^InputTranslation.*$");
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -149,7 +150,7 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testLogOutput() throws Exception {
+  void logOutput() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(TranslationCheck.class);
     checkConfig.addProperty("requiredTranslations", "ja,de");
     checkConfig.addProperty("baseName", "^InputTranslation.*$");
@@ -176,9 +177,9 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
         checker,
         propertyFiles,
         ImmutableMap.of(
-            ":1", Collections.singletonList(" " + firstErrorMessage),
+            ":1", ImmutableList.of(" " + firstErrorMessage),
             "InputTranslationCheckFireErrors_de.properties",
-                Collections.singletonList(line + secondErrorMessage)));
+                ImmutableList.of(line + secondErrorMessage)));
 
     verifyXml(
         getPath("ExpectedTranslationLog.xml"),
@@ -189,7 +190,7 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testOnePropertyFileSet() throws Exception {
+  void onePropertyFileSet() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(TranslationCheck.class);
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     final File[] propertyFiles = {
@@ -199,7 +200,7 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testLogIoExceptionFileNotFound() throws Exception {
+  void logIoExceptionFileNotFound() throws Exception {
     // I can't put wrong file here. Checkstyle fails before check started.
     // I saw some usage of file or handling of wrong file in Checker, or somewhere
     // in checks running part. So I had to do it with reflection to improve coverage.
@@ -231,7 +232,7 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testLogIoException() throws Exception {
+  void logIoException() throws Exception {
     // I can't put wrong file here. Checkstyle fails before check started.
     // I saw some usage of file or handling of wrong file in Checker, or somewhere
     // in checks running part. So I had to do it with reflection to improve coverage.
@@ -263,7 +264,7 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testLogIllegalArgumentException() throws Exception {
+  void logIllegalArgumentException() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(TranslationCheck.class);
     checkConfig.addProperty("baseName", "^bad.*$");
     final String[] expected = {
@@ -277,7 +278,7 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testDefaultTranslationFileIsMissing() throws Exception {
+  void defaultTranslationFileIsMissing() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(TranslationCheck.class);
     checkConfig.addProperty("requiredTranslations", "ja,,, de, ja");
 
@@ -293,7 +294,7 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testTranslationFilesAreMissing() throws Exception {
+  void translationFilesAreMissing() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(TranslationCheck.class);
     checkConfig.addProperty("requiredTranslations", "ja, de");
 
@@ -310,7 +311,7 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testBaseNameWithSeparatorDefaultTranslationIsMissing() throws Exception {
+  void baseNameWithSeparatorDefaultTranslationIsMissing() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(TranslationCheck.class);
     checkConfig.addProperty("requiredTranslations", "fr");
 
@@ -325,7 +326,7 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testBaseNameWithSeparatorTranslationsAreMissing() throws Exception {
+  void baseNameWithSeparatorTranslationsAreMissing() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(TranslationCheck.class);
     checkConfig.addProperty("requiredTranslations", "fr, tr");
 
@@ -342,7 +343,7 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testIsNotMessagesBundle() throws Exception {
+  void isNotMessagesBundle() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(TranslationCheck.class);
     checkConfig.addProperty("requiredTranslations", "de");
 
@@ -355,7 +356,7 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testTranslationFileWithLanguageCountryVariantIsMissing() throws Exception {
+  void translationFileWithLanguageCountryVariantIsMissing() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(TranslationCheck.class);
     checkConfig.addProperty("requiredTranslations", "es, de");
 
@@ -372,7 +373,7 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testTranslationFileWithLanguageCountryVariantArePresent() throws Exception {
+  void translationFileWithLanguageCountryVariantArePresent() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(TranslationCheck.class);
     checkConfig.addProperty("requiredTranslations", "es, fr");
 
@@ -387,7 +388,7 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testBaseNameOption() throws Exception {
+  void baseNameOption() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(TranslationCheck.class);
     checkConfig.addProperty("requiredTranslations", "de, es, fr, ja");
     checkConfig.addProperty("baseName", "^.*Labels$");
@@ -409,7 +410,7 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testFileExtensions() throws Exception {
+  void fileExtensions() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(TranslationCheck.class);
     checkConfig.addProperty("requiredTranslations", "de, es, fr, ja");
     checkConfig.addProperty("fileExtensions", "properties,translation");
@@ -435,7 +436,7 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testEqualBaseNamesButDifferentExtensions() throws Exception {
+  void equalBaseNamesButDifferentExtensions() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(TranslationCheck.class);
     checkConfig.addProperty("requiredTranslations", "de, es, fr, ja");
     checkConfig.addProperty("fileExtensions", "properties,translations");
@@ -461,7 +462,7 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testEqualBaseNamesButDifferentExtensions2() throws Exception {
+  void equalBaseNamesButDifferentExtensions2() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(TranslationCheck.class);
     checkConfig.addProperty("requiredTranslations", "de, es");
     checkConfig.addProperty("fileExtensions", "properties, translations");
@@ -484,7 +485,7 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testRegexpToMatchPartOfBaseName() throws Exception {
+  void regexpToMatchPartOfBaseName() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(TranslationCheck.class);
     checkConfig.addProperty("requiredTranslations", "de, es, fr, ja");
     checkConfig.addProperty("fileExtensions", "properties,translations");
@@ -505,7 +506,7 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testBundlesWithSameNameButDifferentPaths() throws Exception {
+  void bundlesWithSameNameButDifferentPaths() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(TranslationCheck.class);
     checkConfig.addProperty("requiredTranslations", "de");
     checkConfig.addProperty("fileExtensions", "properties");
@@ -524,7 +525,7 @@ public class TranslationCheckTest extends AbstractXmlTestSupport {
   }
 
   @Test
-  public void testWrongUserSpecifiedLanguageCodes() {
+  void wrongUserSpecifiedLanguageCodes() {
     final TranslationCheck check = new TranslationCheck();
     try {
       check.setRequiredTranslations("11");
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/UncommentedMainCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/UncommentedMainCheckTest.java
@@ -22,6 +22,7 @@ package com.puppycrawl.tools.checkstyle.checks;
 import static com.google.common.truth.Truth.assertWithMessage;
 import static com.puppycrawl.tools.checkstyle.checks.UncommentedMainCheck.MSG_KEY;
 
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
@@ -33,7 +34,7 @@ import java.util.List;
 import org.antlr.v4.runtime.CommonToken;
 import org.junit.jupiter.api.Test;
 
-public class UncommentedMainCheckTest extends AbstractModuleTestSupport {
+final class UncommentedMainCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -41,7 +42,7 @@ public class UncommentedMainCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaults() throws Exception {
+  void defaults() throws Exception {
     final String[] expected = {
       "17:5: " + getCheckMessage(MSG_KEY),
       "26:5: " + getCheckMessage(MSG_KEY),
@@ -52,7 +53,7 @@ public class UncommentedMainCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExcludedClasses() throws Exception {
+  void excludedClasses() throws Exception {
     final String[] expected = {
       "17:5: " + getCheckMessage(MSG_KEY),
       "35:5: " + getCheckMessage(MSG_KEY),
@@ -62,7 +63,7 @@ public class UncommentedMainCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokens() {
+  void tokens() {
     final UncommentedMainCheck check = new UncommentedMainCheck();
     assertWithMessage("Required tokens should not be null")
         .that(check.getRequiredTokens())
@@ -79,13 +80,13 @@ public class UncommentedMainCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDeepDepth() throws Exception {
+  void deepDepth() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputUncommentedMain2.java"), expected);
   }
 
   @Test
-  public void testVisitPackage() throws Exception {
+  void visitPackage() throws Exception {
     final String[] expected = {
       "21:5: " + getCheckMessage(MSG_KEY),
     };
@@ -93,19 +94,19 @@ public class UncommentedMainCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWrongName() throws Exception {
+  void wrongName() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputUncommentedMain3.java"), expected);
   }
 
   @Test
-  public void testWrongArrayType() throws Exception {
+  void wrongArrayType() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputUncommentedMain4.java"), expected);
   }
 
   @Test
-  public void testIllegalStateException() {
+  void illegalStateException() {
     final UncommentedMainCheck check = new UncommentedMainCheck();
     final DetailAstImpl ast = new DetailAstImpl();
     ast.initialize(new CommonToken(TokenTypes.CTOR_DEF, "ctor"));
@@ -120,7 +121,7 @@ public class UncommentedMainCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRecords() throws Exception {
+  void records() throws Exception {
 
     final String[] expected = {
       "12:5: " + getCheckMessage(MSG_KEY),
@@ -133,13 +134,13 @@ public class UncommentedMainCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStateIsClearedOnBeginTree() throws Exception {
+  void stateIsClearedOnBeginTree() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(UncommentedMainCheck.class);
     final String file1 = getNonCompilablePath("InputUncommentedMainRecords2.java");
     final String file2 = getNonCompilablePath("InputUncommentedMainBeginTree2.java");
     final List<String> expectedFirstInput =
-        List.of("12:5: " + getCheckMessage(MSG_KEY), "21:24: " + getCheckMessage(MSG_KEY));
-    final List<String> expectedSecondInput = List.of("13:13: " + getCheckMessage(MSG_KEY));
+        ImmutableList.of("12:5: " + getCheckMessage(MSG_KEY), "21:24: " + getCheckMessage(MSG_KEY));
+    final List<String> expectedSecondInput = ImmutableList.of("13:13: " + getCheckMessage(MSG_KEY));
     final File[] inputs = {new File(file1), new File(file2)};
 
     verify(
@@ -151,7 +152,7 @@ public class UncommentedMainCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStateIsClearedOnBeginTree2() throws Exception {
+  void stateIsClearedOnBeginTree2() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(UncommentedMainCheck.class);
     checkConfig.addProperty(
         "excludedClasses", "uncommentedmain\\.InputUncommentedMainBeginTreePackage2");
@@ -159,7 +160,7 @@ public class UncommentedMainCheckTest extends AbstractModuleTestSupport {
     final String file2 = getPath("InputUncommentedMainBeginTreePackage2.java");
     final List<String> expectedFirstInput = List.of(CommonUtil.EMPTY_STRING_ARRAY);
     final List<String> expectedSecondInput =
-        List.of("3:5: " + getCheckMessage(MSG_KEY), "12:5: " + getCheckMessage(MSG_KEY));
+        ImmutableList.of("3:5: " + getCheckMessage(MSG_KEY), "12:5: " + getCheckMessage(MSG_KEY));
     final File[] inputs = {new File(file1), new File(file2)};
 
     verify(
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/UniquePropertiesCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/UniquePropertiesCheckTest.java
@@ -23,6 +23,7 @@ import static com.google.common.truth.Truth.assertWithMessage;
 import static com.puppycrawl.tools.checkstyle.checks.UniquePropertiesCheck.MSG_IO_EXCEPTION_KEY;
 import static com.puppycrawl.tools.checkstyle.checks.UniquePropertiesCheck.MSG_KEY;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.api.FileText;
@@ -36,14 +37,13 @@ import java.lang.reflect.Method;
 import java.nio.file.Files;
 import java.nio.file.NoSuchFileException;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.SortedSet;
 import org.junit.jupiter.api.Test;
 
-public class UniquePropertiesCheckTest extends AbstractModuleTestSupport {
+final class UniquePropertiesCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -55,14 +55,14 @@ public class UniquePropertiesCheckTest extends AbstractModuleTestSupport {
    * valueOf() is uncovered.
    */
   @Test
-  public void testLineSeparatorOptionValueOf() {
+  void lineSeparatorOptionValueOf() {
     final LineSeparatorOption option = LineSeparatorOption.valueOf("CR");
     assertWithMessage("Invalid valueOf result").that(option).isEqualTo(LineSeparatorOption.CR);
   }
 
   /** Tests the ordinal work of a check. */
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(UniquePropertiesCheck.class);
     final String[] expected = {
       "3: " + getCheckMessage(MSG_KEY, "general.exception", 2),
@@ -82,7 +82,7 @@ public class UniquePropertiesCheckTest extends AbstractModuleTestSupport {
    * @noinspectionreason JavadocReference - reference is required to specify method under test
    */
   @Test
-  public void testNotFoundKey() throws Exception {
+  void notFoundKey() throws Exception {
     final List<String> testStrings = new ArrayList<>(3);
     final Method getLineNumber =
         UniquePropertiesCheck.class.getDeclaredMethod(
@@ -100,7 +100,7 @@ public class UniquePropertiesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDuplicatedProperty() throws Exception {
+  void duplicatedProperty() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(UniquePropertiesCheck.class);
     final String[] expected = {
       "2: " + getCheckMessage(MSG_KEY, "key", 2),
@@ -109,7 +109,7 @@ public class UniquePropertiesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testShouldNotProcessFilesWithWrongFileExtension() throws Exception {
+  void shouldNotProcessFilesWithWrongFileExtension() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(UniquePropertiesCheck.class);
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verify(checkConfig, getPath("InputUniqueProperties.txt"), expected);
@@ -117,13 +117,13 @@ public class UniquePropertiesCheckTest extends AbstractModuleTestSupport {
 
   /** Tests IO exception, that can occur during reading of properties file. */
   @Test
-  public void testIoException() throws Exception {
+  void ioException() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(UniquePropertiesCheck.class);
     final UniquePropertiesCheck check = new UniquePropertiesCheck();
     check.configure(checkConfig);
     final String fileName = getPath("InputUniquePropertiesCheckNotExisting.properties");
     final File file = new File(fileName);
-    final FileText fileText = new FileText(file, Collections.emptyList());
+    final FileText fileText = new FileText(file, ImmutableList.of());
     final SortedSet<Violation> violations = check.process(file, fileText);
     assertWithMessage("Wrong messages count: " + violations.size()).that(violations).hasSize(1);
     final Violation violation = violations.iterator().next();
@@ -137,7 +137,7 @@ public class UniquePropertiesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWrongKeyTypeInProperties() throws Exception {
+  void wrongKeyTypeInProperties() throws Exception {
     final Class<?> uniquePropertiesClass =
         Class.forName(
             "com.puppycrawl.tools.checkstyle.checks." + "UniquePropertiesCheck$UniqueProperties");
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/UpperEllCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/UpperEllCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class UpperEllCheckTest extends AbstractModuleTestSupport {
+final class UpperEllCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class UpperEllCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final UpperEllCheck checkObj = new UpperEllCheck();
     final int[] expected = {TokenTypes.NUM_LONG};
     assertWithMessage("Default required tokens are invalid")
@@ -43,7 +43,7 @@ public class UpperEllCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithChecker() throws Exception {
+  void withChecker() throws Exception {
     final String[] expected = {
       "96:40: " + getCheckMessage(MSG_KEY),
     };
@@ -51,7 +51,7 @@ public class UpperEllCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAcceptableTokens() {
+  void acceptableTokens() {
     final int[] expected = {TokenTypes.NUM_LONG};
     final UpperEllCheck check = new UpperEllCheck();
     final int[] actual = check.getAcceptableTokens();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/annotation/AnnotationLocationCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/annotation/AnnotationLocationCheckTest.java
@@ -28,7 +28,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class AnnotationLocationCheckTest extends AbstractModuleTestSupport {
+final class AnnotationLocationCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -36,7 +36,7 @@ public class AnnotationLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final AnnotationLocationCheck checkObj = new AnnotationLocationCheck();
     assertWithMessage(
             "AnnotationLocationCheck#getRequiredTokens should return empty array by default")
@@ -45,14 +45,14 @@ public class AnnotationLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCorrect() throws Exception {
+  void correct() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputAnnotationLocationCorrect.java"), expected);
   }
 
   @Test
-  public void testIncorrectOne() throws Exception {
+  void incorrectOne() throws Exception {
     final String[] expected = {
       "15:11: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION_ALONE, "MyAnn"),
       "20:15: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION_ALONE, "MyAnnotation1"),
@@ -82,7 +82,7 @@ public class AnnotationLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIncorrectTwo() throws Exception {
+  void incorrectTwo() throws Exception {
     final String[] expected = {
       "17:1: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION, "MyAnn_21", 0, 3),
     };
@@ -90,7 +90,7 @@ public class AnnotationLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIncorrectAllTokensOne() throws Exception {
+  void incorrectAllTokensOne() throws Exception {
     final String[] expected = {
       "15:11: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION_ALONE, "MyAnn3"),
       "20:15: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION_ALONE, "MyAnnotation_13"),
@@ -120,7 +120,7 @@ public class AnnotationLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIncorrectAllTokensTwo() throws Exception {
+  void incorrectAllTokensTwo() throws Exception {
     final String[] expected = {
       "17:1: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION, "MyAnn_23", 0, 3),
     };
@@ -128,7 +128,7 @@ public class AnnotationLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final AnnotationLocationCheck constantNameCheckObj = new AnnotationLocationCheck();
     final int[] actual = constantNameCheckObj.getAcceptableTokens();
     final int[] expected = {
@@ -149,13 +149,13 @@ public class AnnotationLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithoutAnnotations() throws Exception {
+  void withoutAnnotations() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAnnotationLocationEmpty.java"), expected);
   }
 
   @Test
-  public void testWithParametersOne() throws Exception {
+  void withParametersOne() throws Exception {
     final String[] expected = {
       "25:9: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION, "MyAnnotation_12", 8, 4),
       "33:9: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION, "MyAnnotation_12", 8, 4),
@@ -174,7 +174,7 @@ public class AnnotationLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithParametersTwo() throws Exception {
+  void withParametersTwo() throws Exception {
     final String[] expected = {
       "17:1: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION, "MyAnn_22", 0, 3),
     };
@@ -182,7 +182,7 @@ public class AnnotationLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithMultipleAnnotations() throws Exception {
+  void withMultipleAnnotations() throws Exception {
     final String[] expected = {
       "14:1: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION_ALONE, "MyAnnotation11"),
       "14:17: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION_ALONE, "MyAnnotation12"),
@@ -193,14 +193,14 @@ public class AnnotationLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllTokens() throws Exception {
+  void allTokens() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputAnnotationLocationWithoutAnnotations.java"), expected);
   }
 
   @Test
-  public void testAnnotation() throws Exception {
+  void annotation() throws Exception {
     final String[] expected = {
       "18:3: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION, "AnnotationAnnotation", 2, 0),
       "20:1: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION_ALONE, "AnnotationAnnotation"),
@@ -211,7 +211,7 @@ public class AnnotationLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClass() throws Exception {
+  void testClass() throws Exception {
     final String[] expected = {
       "18:3: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION, "ClassAnnotation", 2, 0),
       "20:1: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION_ALONE, "ClassAnnotation"),
@@ -224,7 +224,7 @@ public class AnnotationLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEnum() throws Exception {
+  void testEnum() throws Exception {
     final String[] expected = {
       "18:3: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION, "EnumAnnotation", 2, 0),
       "19:1: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION_ALONE, "EnumAnnotation"),
@@ -235,7 +235,7 @@ public class AnnotationLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInterface() throws Exception {
+  void testInterface() throws Exception {
     final String[] expected = {
       "18:3: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION, "InterfaceAnnotation", 2, 0),
       "20:1: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION_ALONE, "InterfaceAnnotation"),
@@ -246,7 +246,7 @@ public class AnnotationLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackage() throws Exception {
+  void testPackage() throws Exception {
     final String[] expected = {
       "12:3: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION, "PackageAnnotation", 2, 0),
       "14:1: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION_ALONE, "PackageAnnotation"),
@@ -255,20 +255,20 @@ public class AnnotationLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationInForEachLoopParameterAndVariableDef() throws Exception {
+  void annotationInForEachLoopParameterAndVariableDef() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputAnnotationLocationDeprecatedAndCustom.java"), expected);
   }
 
   @Test
-  public void testAnnotationMultiple() throws Exception {
+  void annotationMultiple() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAnnotationLocationMultiple.java"), expected);
   }
 
   @Test
-  public void testAnnotationParameterized() throws Exception {
+  void annotationParameterized() throws Exception {
     final String[] expected = {
       "18:5: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION_ALONE, "Annotation"),
       "20:5: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION_ALONE, "Annotation"),
@@ -282,7 +282,7 @@ public class AnnotationLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationSingleParameterless() throws Exception {
+  void annotationSingleParameterless() throws Exception {
     final String[] expected = {
       "23:17: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION_ALONE, "Annotation"),
       "25:5: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION_ALONE, "Annotation"),
@@ -297,7 +297,7 @@ public class AnnotationLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationLocationRecordsAndCompactCtors() throws Exception {
+  void annotationLocationRecordsAndCompactCtors() throws Exception {
     final String[] expected = {
       "20:5: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION_ALONE, "SuppressWarnings"),
       "24:5: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION_ALONE, "SuppressWarnings"),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/annotation/AnnotationOnSameLineCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/annotation/AnnotationOnSameLineCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class AnnotationOnSameLineCheckTest extends AbstractModuleTestSupport {
+final class AnnotationOnSameLineCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class AnnotationOnSameLineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final AnnotationOnSameLineCheck check = new AnnotationOnSameLineCheck();
     assertWithMessage(
             "AnnotationOnSameLineCheck#getRequiredTokens should return empty array by default")
@@ -44,7 +44,7 @@ public class AnnotationOnSameLineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final AnnotationOnSameLineCheck constantNameCheckObj = new AnnotationOnSameLineCheck();
     final int[] actual = constantNameCheckObj.getAcceptableTokens();
     final int[] expected = {
@@ -70,7 +70,7 @@ public class AnnotationOnSameLineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCheck() throws Exception {
+  void check() throws Exception {
     final String[] expected = {
       "17:5: " + getCheckMessage(MSG_KEY_ANNOTATION_ON_SAME_LINE, "Annotation"),
       "18:5: " + getCheckMessage(MSG_KEY_ANNOTATION_ON_SAME_LINE, "Annotation"),
@@ -81,7 +81,7 @@ public class AnnotationOnSameLineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCheckAcceptableTokens() throws Exception {
+  void checkAcceptableTokens() throws Exception {
     final String[] expected = {
       "18:5: " + getCheckMessage(MSG_KEY_ANNOTATION_ON_SAME_LINE, "Annotation3"),
       "19:5: " + getCheckMessage(MSG_KEY_ANNOTATION_ON_SAME_LINE, "Annotation"),
@@ -92,7 +92,7 @@ public class AnnotationOnSameLineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCheck2() throws Exception {
+  void check2() throws Exception {
     final String[] expected = {
       "19:5: " + getCheckMessage(MSG_KEY_ANNOTATION_ON_SAME_LINE, "Ann"),
       "24:5: " + getCheckMessage(MSG_KEY_ANNOTATION_ON_SAME_LINE, "SuppressWarnings"),
@@ -103,7 +103,7 @@ public class AnnotationOnSameLineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCheckOnDifferentTokens() throws Exception {
+  void checkOnDifferentTokens() throws Exception {
     final String[] expected = {
       "14:1: " + getCheckMessage(MSG_KEY_ANNOTATION_ON_SAME_LINE, "Ann"),
       "17:5: " + getCheckMessage(MSG_KEY_ANNOTATION_ON_SAME_LINE, "Ann"),
@@ -127,7 +127,7 @@ public class AnnotationOnSameLineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationOnSameLineRecordsAndCompactCtors() throws Exception {
+  void annotationOnSameLineRecordsAndCompactCtors() throws Exception {
     final String[] expected = {
       "13:5: " + getCheckMessage(MSG_KEY_ANNOTATION_ON_SAME_LINE, "NonNull1"),
       "17:5: " + getCheckMessage(MSG_KEY_ANNOTATION_ON_SAME_LINE, "SuppressWarnings"),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/annotation/AnnotationUseStyleCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/annotation/AnnotationUseStyleCheckTest.java
@@ -33,7 +33,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import de.thetaphi.forbiddenapis.SuppressForbidden;
 import org.junit.jupiter.api.Test;
 
-public class AnnotationUseStyleCheckTest extends AbstractModuleTestSupport {
+final class AnnotationUseStyleCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -45,7 +45,7 @@ public class AnnotationUseStyleCheckTest extends AbstractModuleTestSupport {
    * valueOf() is uncovered.
    */
   @Test
-  public void testElementStyleOptionValueOf() {
+  void elementStyleOptionValueOf() {
     final AnnotationUseStyleCheck.ElementStyleOption option =
         AnnotationUseStyleCheck.ElementStyleOption.valueOf("COMPACT");
     assertWithMessage("Invalid valueOf result")
@@ -58,7 +58,7 @@ public class AnnotationUseStyleCheckTest extends AbstractModuleTestSupport {
    * valueOf() is uncovered.
    */
   @Test
-  public void testTrailingArrayCommaOptionValueOf() {
+  void trailingArrayCommaOptionValueOf() {
     final AnnotationUseStyleCheck.TrailingArrayCommaOption option =
         AnnotationUseStyleCheck.TrailingArrayCommaOption.valueOf("ALWAYS");
     assertWithMessage("Invalid valueOf result")
@@ -71,7 +71,7 @@ public class AnnotationUseStyleCheckTest extends AbstractModuleTestSupport {
    * valueOf() is uncovered.
    */
   @Test
-  public void testClosingParensOptionValueOf() {
+  void closingParensOptionValueOf() {
     final AnnotationUseStyleCheck.ClosingParensOption option =
         AnnotationUseStyleCheck.ClosingParensOption.valueOf("ALWAYS");
     assertWithMessage("Invalid valueOf result")
@@ -88,7 +88,7 @@ public class AnnotationUseStyleCheckTest extends AbstractModuleTestSupport {
    */
   @SuppressForbidden
   @Test
-  public void testNonTrimmedInput() throws Exception {
+  void nonTrimmedInput() throws Exception {
     final DefaultConfiguration configuration = createModuleConfig(AnnotationUseStyleCheck.class);
     configuration.addProperty("elementStyle", "ignore");
     configuration.addProperty("closingParens", " ignore  ");
@@ -100,7 +100,7 @@ public class AnnotationUseStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "13:1: " + getCheckMessage(MSG_KEY_ANNOTATION_INCORRECT_STYLE, "COMPACT_NO_ARRAY"),
       "14:1: " + getCheckMessage(MSG_KEY_ANNOTATION_INCORRECT_STYLE, "COMPACT_NO_ARRAY"),
@@ -123,7 +123,7 @@ public class AnnotationUseStyleCheckTest extends AbstractModuleTestSupport {
 
   /** Test that annotation parens are always present. */
   @Test
-  public void testParensAlways() throws Exception {
+  void parensAlways() throws Exception {
     final String[] expected = {
       "12:1: " + getCheckMessage(MSG_KEY_ANNOTATION_PARENS_MISSING),
       "27:1: " + getCheckMessage(MSG_KEY_ANNOTATION_PARENS_MISSING),
@@ -139,7 +139,7 @@ public class AnnotationUseStyleCheckTest extends AbstractModuleTestSupport {
 
   /** Test that annotation parens are never present. */
   @Test
-  public void testParensNever() throws Exception {
+  void parensNever() throws Exception {
     final String[] expected = {
       "22:1: " + getCheckMessage(MSG_KEY_ANNOTATION_PARENS_PRESENT),
       "40:1: " + getCheckMessage(MSG_KEY_ANNOTATION_PARENS_PRESENT),
@@ -152,7 +152,7 @@ public class AnnotationUseStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStyleExpanded() throws Exception {
+  void styleExpanded() throws Exception {
     final String[] expected = {
       "14:1: " + getCheckMessage(MSG_KEY_ANNOTATION_INCORRECT_STYLE, "EXPANDED"),
       "21:1: " + getCheckMessage(MSG_KEY_ANNOTATION_INCORRECT_STYLE, "EXPANDED"),
@@ -170,7 +170,7 @@ public class AnnotationUseStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStyleCompact() throws Exception {
+  void styleCompact() throws Exception {
     final String[] expected = {
       "52:5: " + getCheckMessage(MSG_KEY_ANNOTATION_INCORRECT_STYLE, "COMPACT"),
       "56:1: " + getCheckMessage(MSG_KEY_ANNOTATION_INCORRECT_STYLE, "COMPACT"),
@@ -183,7 +183,7 @@ public class AnnotationUseStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStyleCompactNoArray() throws Exception {
+  void styleCompactNoArray() throws Exception {
     final String[] expected = {
       "13:1: " + getCheckMessage(MSG_KEY_ANNOTATION_INCORRECT_STYLE, "COMPACT_NO_ARRAY"),
       "14:1: " + getCheckMessage(MSG_KEY_ANNOTATION_INCORRECT_STYLE, "COMPACT_NO_ARRAY"),
@@ -200,7 +200,7 @@ public class AnnotationUseStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommaAlwaysViolations() throws Exception {
+  void commaAlwaysViolations() throws Exception {
     final String[] expected = {
       "12:20: " + getCheckMessage(MSG_KEY_ANNOTATION_TRAILING_COMMA_MISSING),
       "15:30: " + getCheckMessage(MSG_KEY_ANNOTATION_TRAILING_COMMA_MISSING),
@@ -221,7 +221,7 @@ public class AnnotationUseStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommaAlwaysViolationsNonCompilable() throws Exception {
+  void commaAlwaysViolationsNonCompilable() throws Exception {
     final String[] expected = {
       "15:37: " + getCheckMessage(MSG_KEY_ANNOTATION_TRAILING_COMMA_MISSING),
       "15:65: " + getCheckMessage(MSG_KEY_ANNOTATION_TRAILING_COMMA_MISSING),
@@ -232,7 +232,7 @@ public class AnnotationUseStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommaAlwaysNoViolations() throws Exception {
+  void commaAlwaysNoViolations() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -240,7 +240,7 @@ public class AnnotationUseStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommaAlwaysNoViolationsNonCompilable() throws Exception {
+  void commaAlwaysNoViolationsNonCompilable() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -248,7 +248,7 @@ public class AnnotationUseStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTrailingArrayIgnore() throws Exception {
+  void trailingArrayIgnore() throws Exception {
     final String[] expected = {
       "15:5: " + getCheckMessage(MSG_KEY_ANNOTATION_INCORRECT_STYLE, "COMPACT_NO_ARRAY"),
       "23:13: " + getCheckMessage(MSG_KEY_ANNOTATION_INCORRECT_STYLE, "COMPACT_NO_ARRAY"),
@@ -261,7 +261,7 @@ public class AnnotationUseStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommaNeverViolations() throws Exception {
+  void commaNeverViolations() throws Exception {
     final String[] expected = {
       "16:32: " + getCheckMessage(MSG_KEY_ANNOTATION_TRAILING_COMMA_PRESENT),
       "21:42: " + getCheckMessage(MSG_KEY_ANNOTATION_TRAILING_COMMA_PRESENT),
@@ -278,7 +278,7 @@ public class AnnotationUseStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommaNeverNoViolations() throws Exception {
+  void commaNeverNoViolations() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -286,21 +286,21 @@ public class AnnotationUseStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEverythingMixed() throws Exception {
+  void everythingMixed() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputAnnotationUseStyleEverythingMixed.java"), expected);
   }
 
   @Test
-  public void testAnnotationsWithoutDefaultValues() throws Exception {
+  void annotationsWithoutDefaultValues() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputAnnotationUseStyleParams.java"), expected);
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final AnnotationUseStyleCheck constantNameCheckObj = new AnnotationUseStyleCheck();
     final int[] actual = constantNameCheckObj.getAcceptableTokens();
     final int[] expected = {TokenTypes.ANNOTATION};
@@ -308,7 +308,7 @@ public class AnnotationUseStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetOption() {
+  void getOption() {
     final AnnotationUseStyleCheck check = new AnnotationUseStyleCheck();
     try {
       check.setElementStyle("SHOULD_PRODUCE_ERROR");
@@ -323,7 +323,7 @@ public class AnnotationUseStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStyleNotInList() throws Exception {
+  void styleNotInList() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputAnnotationUseStyle.java"), expected);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/annotation/MissingDeprecatedCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/annotation/MissingDeprecatedCheckTest.java
@@ -28,7 +28,7 @@ import com.puppycrawl.tools.checkstyle.api.JavadocTokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class MissingDeprecatedCheckTest extends AbstractModuleTestSupport {
+final class MissingDeprecatedCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -36,7 +36,7 @@ public class MissingDeprecatedCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetDefaultJavadocTokens() {
+  void getDefaultJavadocTokens() {
     final MissingDeprecatedCheck missingDeprecatedCheck = new MissingDeprecatedCheck();
     final int[] expected = {
       JavadocTokenTypes.JAVADOC,
@@ -48,7 +48,7 @@ public class MissingDeprecatedCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredJavadocTokens() {
+  void getRequiredJavadocTokens() {
     final MissingDeprecatedCheck checkObj = new MissingDeprecatedCheck();
     final int[] expected = {
       JavadocTokenTypes.JAVADOC,
@@ -60,7 +60,7 @@ public class MissingDeprecatedCheckTest extends AbstractModuleTestSupport {
 
   /** Tests that members that are only deprecated via javadoc are flagged. */
   @Test
-  public void testBadDeprecatedAnnotation() throws Exception {
+  void badDeprecatedAnnotation() throws Exception {
 
     final String[] expected = {
       "14: " + getCheckMessage(MSG_KEY_ANNOTATION_MISSING_DEPRECATED),
@@ -79,7 +79,7 @@ public class MissingDeprecatedCheckTest extends AbstractModuleTestSupport {
 
   /** Tests that members that are only deprecated via the annotation are flagged. */
   @Test
-  public void testBadDeprecatedJavadoc() throws Exception {
+  void badDeprecatedJavadoc() throws Exception {
 
     final String[] expected = {
       "18: " + getCheckMessage(MSG_KEY_ANNOTATION_MISSING_DEPRECATED),
@@ -94,7 +94,7 @@ public class MissingDeprecatedCheckTest extends AbstractModuleTestSupport {
 
   /** Tests various special deprecation conditions such as duplicate or empty tags. */
   @Test
-  public void testSpecialCaseDeprecated() throws Exception {
+  void specialCaseDeprecated() throws Exception {
 
     final String[] expected = {
       "12: " + getCheckMessage(MSG_KEY_JAVADOC_DUPLICATE_TAG, "@deprecated"),
@@ -114,7 +114,7 @@ public class MissingDeprecatedCheckTest extends AbstractModuleTestSupport {
 
   /** Tests that good forms of deprecation are not flagged. */
   @Test
-  public void testGoodDeprecated() throws Exception {
+  void goodDeprecated() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -122,7 +122,7 @@ public class MissingDeprecatedCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTwoInJavadocWithoutAnnotation() throws Exception {
+  void twoInJavadocWithoutAnnotation() throws Exception {
 
     final String[] expected = {
       "15: " + getCheckMessage(MSG_KEY_JAVADOC_DUPLICATE_TAG, "@deprecated"),
@@ -133,7 +133,7 @@ public class MissingDeprecatedCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyJavadocLine() throws Exception {
+  void emptyJavadocLine() throws Exception {
 
     final String[] expected = {
       "18: " + getCheckMessage(MSG_KEY_ANNOTATION_MISSING_DEPRECATED),
@@ -143,7 +143,7 @@ public class MissingDeprecatedCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackageInfo() throws Exception {
+  void packageInfo() throws Exception {
 
     final String[] expected = {
       "9: " + getCheckMessage(MSG_KEY_ANNOTATION_MISSING_DEPRECATED),
@@ -153,7 +153,7 @@ public class MissingDeprecatedCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDepPackageInfoBelowComment() throws Exception {
+  void depPackageInfoBelowComment() throws Exception {
 
     final String[] expected = {
       "14: " + getCheckMessage(MSG_KEY_ANNOTATION_MISSING_DEPRECATED),
@@ -163,7 +163,7 @@ public class MissingDeprecatedCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackageInfoBelowComment() throws Exception {
+  void packageInfoBelowComment() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/annotation/MissingOverrideCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/annotation/MissingOverrideCheckTest.java
@@ -28,7 +28,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class MissingOverrideCheckTest extends AbstractModuleTestSupport {
+final class MissingOverrideCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -40,7 +40,7 @@ public class MissingOverrideCheckTest extends AbstractModuleTestSupport {
    * including the inheritDoc tag.
    */
   @Test
-  public void testBadOverrideFromObject() throws Exception {
+  void badOverrideFromObject() throws Exception {
 
     final String[] expected = {
       "15:5: " + getCheckMessage(MSG_KEY_ANNOTATION_MISSING_OVERRIDE),
@@ -59,7 +59,7 @@ public class MissingOverrideCheckTest extends AbstractModuleTestSupport {
    * including the inheritDoc tag even in Java 5 compatibility mode.
    */
   @Test
-  public void testBadOverrideFromObjectJ5Compatible() throws Exception {
+  void badOverrideFromObjectJ5Compatible() throws Exception {
 
     final String[] expected = {
       "15:5: " + getCheckMessage(MSG_KEY_ANNOTATION_MISSING_OVERRIDE),
@@ -77,7 +77,7 @@ public class MissingOverrideCheckTest extends AbstractModuleTestSupport {
    * including the inheritDoc tag.
    */
   @Test
-  public void testBadOverrideFromOther() throws Exception {
+  void badOverrideFromOther() throws Exception {
     final String[] expected = {
       "17:3: " + getCheckMessage(MSG_KEY_ANNOTATION_MISSING_OVERRIDE),
       "33:3: " + getCheckMessage(MSG_KEY_ANNOTATION_MISSING_OVERRIDE),
@@ -100,7 +100,7 @@ public class MissingOverrideCheckTest extends AbstractModuleTestSupport {
    * compatibility mode.
    */
   @Test
-  public void testBadOverrideFromOtherJ5Compatible() throws Exception {
+  void badOverrideFromOtherJ5Compatible() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -113,7 +113,7 @@ public class MissingOverrideCheckTest extends AbstractModuleTestSupport {
    * including the inheritDoc tag.
    */
   @Test
-  public void testBadAnnotationOverride() throws Exception {
+  void badAnnotationOverride() throws Exception {
     final String[] expected = {
       "17:5: " + getCheckMessage(MSG_KEY_ANNOTATION_MISSING_OVERRIDE),
       "23:9: " + getCheckMessage(MSG_KEY_ANNOTATION_MISSING_OVERRIDE),
@@ -129,7 +129,7 @@ public class MissingOverrideCheckTest extends AbstractModuleTestSupport {
    * compatibility mode.
    */
   @Test
-  public void testBadAnnotationOverrideJ5Compatible() throws Exception {
+  void badAnnotationOverrideJ5Compatible() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputMissingOverrideBadAnnotationJava5.java"), expected);
@@ -139,7 +139,7 @@ public class MissingOverrideCheckTest extends AbstractModuleTestSupport {
    * Tests that inheritDoc misuse is properly flagged or missing Javadocs do not cause a problem.
    */
   @Test
-  public void testNotOverride() throws Exception {
+  void notOverride() throws Exception {
     final String[] expected = {
       "15:3: " + getCheckMessage(MSG_KEY_TAG_NOT_VALID_ON, "{@inheritDoc}"),
       "20:3: " + getCheckMessage(MSG_KEY_TAG_NOT_VALID_ON, "{@inheritDoc}"),
@@ -153,7 +153,7 @@ public class MissingOverrideCheckTest extends AbstractModuleTestSupport {
    * including the inheritDoc tag.
    */
   @Test
-  public void testGoodOverrideFromObject() throws Exception {
+  void goodOverrideFromObject() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -166,7 +166,7 @@ public class MissingOverrideCheckTest extends AbstractModuleTestSupport {
    * including the inheritDoc tag even in Java 5 compatibility mode.
    */
   @Test
-  public void testGoodOverrideFromObjectJ5Compatible() throws Exception {
+  void goodOverrideFromObjectJ5Compatible() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -179,7 +179,7 @@ public class MissingOverrideCheckTest extends AbstractModuleTestSupport {
    * including the inheritDoc tag.
    */
   @Test
-  public void testGoodOverrideFromOther() throws Exception {
+  void goodOverrideFromOther() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -191,7 +191,7 @@ public class MissingOverrideCheckTest extends AbstractModuleTestSupport {
    * compatibility mode.
    */
   @Test
-  public void testGoodOverrideFromOtherJ5Compatible() throws Exception {
+  void goodOverrideFromOtherJ5Compatible() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -204,7 +204,7 @@ public class MissingOverrideCheckTest extends AbstractModuleTestSupport {
    * including the inheritDoc tag.
    */
   @Test
-  public void testGoodAnnotationOverride() throws Exception {
+  void goodAnnotationOverride() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputMissingOverrideGoodOverride.java"), expected);
@@ -215,14 +215,14 @@ public class MissingOverrideCheckTest extends AbstractModuleTestSupport {
    * compatibility mode.
    */
   @Test
-  public void testGoodAnnotationOverrideJ5Compatible() throws Exception {
+  void goodAnnotationOverrideJ5Compatible() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputMissingOverrideGoodOverrideJava5.java"), expected);
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final int[] expectedTokens = {TokenTypes.METHOD_DEF};
     final MissingOverrideCheck check = new MissingOverrideCheck();
     final int[] actual = check.getAcceptableTokens();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/annotation/PackageAnnotationCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/annotation/PackageAnnotationCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class PackageAnnotationCheckTest extends AbstractModuleTestSupport {
+final class PackageAnnotationCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -36,7 +36,7 @@ public class PackageAnnotationCheckTest extends AbstractModuleTestSupport {
 
   /** This tests a package annotation that is in the package-info.java file. */
   @Test
-  public void testGoodPackageAnnotation() throws Exception {
+  void goodPackageAnnotation() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -44,7 +44,7 @@ public class PackageAnnotationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final PackageAnnotationCheck constantNameCheckObj = new PackageAnnotationCheck();
     final int[] actual = constantNameCheckObj.getAcceptableTokens();
     final int[] expected = {TokenTypes.PACKAGE_DEF};
@@ -52,7 +52,7 @@ public class PackageAnnotationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoPackageAnnotation() throws Exception {
+  void noPackageAnnotation() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -60,7 +60,7 @@ public class PackageAnnotationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBadPackageAnnotation() throws Exception {
+  void badPackageAnnotation() throws Exception {
 
     final String[] expected = {
       "10:1: " + getCheckMessage(MSG_KEY),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/annotation/SuppressWarningsCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/annotation/SuppressWarningsCheckTest.java
@@ -25,7 +25,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
+final class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
 
   /** Tests SuppressWarnings with default regex. */
   @Test
-  public void testSingleDefault() throws Exception {
+  void singleDefault() throws Exception {
 
     final String[] expected = {
       "18:23: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "   "),
@@ -53,7 +53,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
 
   /** Tests SuppressWarnings all warnings disabled on everything. */
   @Test
-  public void testSingleAll() throws Exception {
+  void singleAll() throws Exception {
 
     final String[] expected = {
       "15:19: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -91,7 +91,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
 
   /** Tests SuppressWarnings unchecked warning disabled on everything. */
   @Test
-  public void testSingleNoUnchecked() throws Exception {
+  void singleNoUnchecked() throws Exception {
 
     final String[] expected = {
       "15:19: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -110,7 +110,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
 
   /** Tests SuppressWarnings unchecked warning disabled on certain tokens. */
   @Test
-  public void testSingleNoUncheckedTokens() throws Exception {
+  void singleNoUncheckedTokens() throws Exception {
 
     final String[] expected = {
       "13:19: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -126,7 +126,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
 
   /** Tests SuppressWarnings un* warning disabled on everything. */
   @Test
-  public void testSingleNoUnWildcard() throws Exception {
+  void singleNoUnWildcard() throws Exception {
 
     final String[] expected = {
       "15:19: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -154,7 +154,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
 
   /** Tests SuppressWarnings unchecked, unused warning disabled on everything. */
   @Test
-  public void testSingleNoUncheckedUnused() throws Exception {
+  void singleNoUncheckedUnused() throws Exception {
 
     final String[] expected = {
       "15:19: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -179,7 +179,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
 
   /** Tests SuppressWarnings *, unchecked, unused warning disabled on everything. */
   @Test
-  public void testSingleNoUncheckedUnusedAll() throws Exception {
+  void singleNoUncheckedUnusedAll() throws Exception {
 
     final String[] expected = {
       "15:19: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -217,7 +217,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
 
   /** Tests SuppressWarnings with default regex. */
   @Test
-  public void testCompactDefault() throws Exception {
+  void compactDefault() throws Exception {
 
     final String[] expected = {
       "18:24: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "   "),
@@ -230,7 +230,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCompactDefaultNonConstant() throws Exception {
+  void compactDefaultNonConstant() throws Exception {
 
     final String[] expected = {
       "18:24: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "   "),
@@ -255,7 +255,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
 
   /** Tests SuppressWarnings all warnings disabled on everything. */
   @Test
-  public void testCompactAll() throws Exception {
+  void compactAll() throws Exception {
 
     final String[] expected = {
       "15:20: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -281,7 +281,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCompactAllNonConstant() throws Exception {
+  void compactAllNonConstant() throws Exception {
 
     final String[] expected = {
       "15:20: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -334,7 +334,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
 
   /** Tests SuppressWarnings unchecked warning disabled on everything. */
   @Test
-  public void testCompactNoUnchecked() throws Exception {
+  void compactNoUnchecked() throws Exception {
 
     final String[] expected = {
       "15:20: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -349,7 +349,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
 
   /** Tests SuppressWarnings unchecked warning disabled on certain tokens. */
   @Test
-  public void testCompactNoUncheckedTokens() throws Exception {
+  void compactNoUncheckedTokens() throws Exception {
 
     final String[] expected = {
       "13:20: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -359,7 +359,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCompactNoUncheckedTokensNonConstant() throws Exception {
+  void compactNoUncheckedTokensNonConstant() throws Exception {
 
     final String[] expected = {
       "13:20: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -373,7 +373,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
 
   /** Tests SuppressWarnings un* warning disabled on everything. */
   @Test
-  public void testCompactNoUnWildcard() throws Exception {
+  void compactNoUnWildcard() throws Exception {
 
     final String[] expected = {
       "15:20: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -392,7 +392,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCompactNoUnWildcardNonConstant() throws Exception {
+  void compactNoUnWildcardNonConstant() throws Exception {
 
     final String[] expected = {
       "15:20: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -426,7 +426,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
 
   /** Tests SuppressWarnings unchecked, unused warning disabled on everything. */
   @Test
-  public void testCompactNoUncheckedUnused() throws Exception {
+  void compactNoUncheckedUnused() throws Exception {
 
     final String[] expected = {
       "15:20: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -444,7 +444,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCompactNoUncheckedUnusedNonConstant() throws Exception {
+  void compactNoUncheckedUnusedNonConstant() throws Exception {
 
     final String[] expected = {
       "15:20: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -477,7 +477,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
 
   /** Tests SuppressWarnings *, unchecked, unused warning disabled on everything. */
   @Test
-  public void testCompactNoUncheckedUnusedAll() throws Exception {
+  void compactNoUncheckedUnusedAll() throws Exception {
 
     final String[] expected = {
       "15:20: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -503,7 +503,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCompactNoUncheckedUnusedAllNonConstant() throws Exception {
+  void compactNoUncheckedUnusedAllNonConstant() throws Exception {
 
     final String[] expected = {
       "15:20: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -556,7 +556,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
 
   /** Tests SuppressWarnings with default regex. */
   @Test
-  public void testExpandedDefault() throws Exception {
+  void expandedDefault() throws Exception {
 
     final String[] expected = {
       "18:30: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "   "),
@@ -569,7 +569,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExpandedDefaultNonConstant() throws Exception {
+  void expandedDefaultNonConstant() throws Exception {
 
     final String[] expected = {
       "18:30: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "   "),
@@ -594,7 +594,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
 
   /** Tests SuppressWarnings all warnings disabled on everything. */
   @Test
-  public void testExpandedAll() throws Exception {
+  void expandedAll() throws Exception {
 
     final String[] expected = {
       "15:26: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -620,7 +620,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExpandedAllNonConstant() throws Exception {
+  void expandedAllNonConstant() throws Exception {
 
     final String[] expected = {
       "15:26: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -673,7 +673,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
 
   /** Tests SuppressWarnings unchecked warning disabled on everything. */
   @Test
-  public void testExpandedNoUnchecked() throws Exception {
+  void expandedNoUnchecked() throws Exception {
 
     final String[] expected = {
       "15:26: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -687,7 +687,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExpandedNoUncheckedNonConstant() throws Exception {
+  void expandedNoUncheckedNonConstant() throws Exception {
 
     final String[] expected = {
       "15:26: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -711,7 +711,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
 
   /** Tests SuppressWarnings unchecked warning disabled on certain tokens. */
   @Test
-  public void testExpandedNoUncheckedTokens() throws Exception {
+  void expandedNoUncheckedTokens() throws Exception {
 
     final String[] expected = {
       "13:26: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -721,7 +721,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExpandedNoUncheckedTokensNonConstant() throws Exception {
+  void expandedNoUncheckedTokensNonConstant() throws Exception {
 
     final String[] expected = {
       "13:26: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -735,7 +735,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
 
   /** Tests SuppressWarnings un* warning disabled on everything. */
   @Test
-  public void testExpandedNoUnWildcard() throws Exception {
+  void expandedNoUnWildcard() throws Exception {
 
     final String[] expected = {
       "15:26: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -754,7 +754,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExpandedNoUnWildcardNonConstant() throws Exception {
+  void expandedNoUnWildcardNonConstant() throws Exception {
 
     final String[] expected = {
       "15:26: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -788,7 +788,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
 
   /** Tests SuppressWarnings unchecked, unused warning disabled on everything. */
   @Test
-  public void testExpandedNoUncheckedUnused() throws Exception {
+  void expandedNoUncheckedUnused() throws Exception {
 
     final String[] expected = {
       "15:26: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -806,7 +806,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExpandedNoUncheckedUnusedNonConstant() throws Exception {
+  void expandedNoUncheckedUnusedNonConstant() throws Exception {
 
     final String[] expected = {
       "15:26: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -839,7 +839,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
 
   /** Tests SuppressWarnings *, unchecked, unused warning disabled on everything. */
   @Test
-  public void testExpandedNoUncheckedUnusedAll() throws Exception {
+  void expandedNoUncheckedUnusedAll() throws Exception {
 
     final String[] expected = {
       "15:26: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -865,7 +865,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExpandedNoUncheckedUnusedAllNonConstant() throws Exception {
+  void expandedNoUncheckedUnusedAllNonConstant() throws Exception {
 
     final String[] expected = {
       "15:26: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
@@ -917,7 +917,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUncheckedInConstant() throws Exception {
+  void uncheckedInConstant() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -925,7 +925,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValuePairAnnotation() throws Exception {
+  void valuePairAnnotation() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -933,7 +933,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWorkingProperlyOnComplexAnnotations() throws Exception {
+  void workingProperlyOnComplexAnnotations() throws Exception {
 
     final String[] expected = {
       "30:34: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, ""),
@@ -945,7 +945,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWorkingProperlyOnComplexAnnotationsNonConstant() throws Exception {
+  void workingProperlyOnComplexAnnotationsNonConstant() throws Exception {
 
     final String[] expected = {
       "30:34: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, ""),
@@ -959,7 +959,7 @@ public class SuppressWarningsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSuppressWarningsRecords() throws Exception {
+  void suppressWarningsRecords() throws Exception {
 
     final String[] expected = {
       "24:28: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unchecked"),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/blocks/AvoidNestedBlocksCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/blocks/AvoidNestedBlocksCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class AvoidNestedBlocksCheckTest extends AbstractModuleTestSupport {
+final class AvoidNestedBlocksCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class AvoidNestedBlocksCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final AvoidNestedBlocksCheck checkObj = new AvoidNestedBlocksCheck();
     final int[] expected = {TokenTypes.SLIST};
     assertWithMessage("Default required tokens are invalid")
@@ -43,7 +43,7 @@ public class AvoidNestedBlocksCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStrictSettings() throws Exception {
+  void strictSettings() throws Exception {
     final String[] expected = {
       "25:9: " + getCheckMessage(MSG_KEY_BLOCK_NESTED),
       "47:17: " + getCheckMessage(MSG_KEY_BLOCK_NESTED),
@@ -54,7 +54,7 @@ public class AvoidNestedBlocksCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowSwitchInCase() throws Exception {
+  void allowSwitchInCase() throws Exception {
 
     final String[] expected = {
       "21:9: " + getCheckMessage(MSG_KEY_BLOCK_NESTED),
@@ -65,7 +65,7 @@ public class AvoidNestedBlocksCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final AvoidNestedBlocksCheck constantNameCheckObj = new AvoidNestedBlocksCheck();
     final int[] actual = constantNameCheckObj.getAcceptableTokens();
     final int[] expected = {TokenTypes.SLIST};
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/blocks/EmptyBlockCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/blocks/EmptyBlockCheckTest.java
@@ -28,7 +28,7 @@ import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class EmptyBlockCheckTest extends AbstractModuleTestSupport {
+final class EmptyBlockCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -40,13 +40,13 @@ public class EmptyBlockCheckTest extends AbstractModuleTestSupport {
    * valueOf() is uncovered.
    */
   @Test
-  public void testBlockOptionValueOf() {
+  void blockOptionValueOf() {
     final BlockOption option = BlockOption.valueOf("TEXT");
     assertWithMessage("Invalid valueOf result").that(option).isEqualTo(BlockOption.TEXT);
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "38:13: " + getCheckMessage(MSG_KEY_BLOCK_NO_STATEMENT),
       "40:17: " + getCheckMessage(MSG_KEY_BLOCK_NO_STATEMENT),
@@ -61,7 +61,7 @@ public class EmptyBlockCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testText() throws Exception {
+  void text() throws Exception {
     final String[] expected = {
       "38:13: " + getCheckMessage(MSG_KEY_BLOCK_EMPTY, "try"),
       "40:17: " + getCheckMessage(MSG_KEY_BLOCK_EMPTY, "finally"),
@@ -73,7 +73,7 @@ public class EmptyBlockCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStatement() throws Exception {
+  void statement() throws Exception {
     final String[] expected = {
       "38:13: " + getCheckMessage(MSG_KEY_BLOCK_NO_STATEMENT),
       "40:17: " + getCheckMessage(MSG_KEY_BLOCK_NO_STATEMENT),
@@ -88,7 +88,7 @@ public class EmptyBlockCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void allowEmptyLoops() throws Exception {
+  void allowEmptyLoops() throws Exception {
     final String[] expected = {
       "21:21: " + getCheckMessage(MSG_KEY_BLOCK_NO_STATEMENT),
       "24:34: " + getCheckMessage(MSG_KEY_BLOCK_NO_STATEMENT),
@@ -99,7 +99,7 @@ public class EmptyBlockCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void allowEmptyLoopsText() throws Exception {
+  void allowEmptyLoopsText() throws Exception {
     final String[] expected = {
       "26:21: " + getCheckMessage(MSG_KEY_BLOCK_EMPTY, "if"),
       "29:34: " + getCheckMessage(MSG_KEY_BLOCK_EMPTY, "if"),
@@ -110,7 +110,7 @@ public class EmptyBlockCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidOption() throws Exception {
+  void invalidOption() throws Exception {
 
     try {
       final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -129,7 +129,7 @@ public class EmptyBlockCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowEmptyCaseWithText() throws Exception {
+  void allowEmptyCaseWithText() throws Exception {
     final String[] expected = {
       "16:28: " + getCheckMessage(MSG_KEY_BLOCK_EMPTY, "case"),
       "22:13: " + getCheckMessage(MSG_KEY_BLOCK_EMPTY, "case"),
@@ -141,7 +141,7 @@ public class EmptyBlockCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testForbidCaseWithoutStmt() throws Exception {
+  void forbidCaseWithoutStmt() throws Exception {
     final String[] expected = {
       "16:28: " + getCheckMessage(MSG_KEY_BLOCK_NO_STATEMENT, "case"),
       "22:13: " + getCheckMessage(MSG_KEY_BLOCK_NO_STATEMENT, "case"),
@@ -155,7 +155,7 @@ public class EmptyBlockCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowEmptyDefaultWithText() throws Exception {
+  void allowEmptyDefaultWithText() throws Exception {
     final String[] expected = {
       "15:30: " + getCheckMessage(MSG_KEY_BLOCK_EMPTY, "default"),
       "21:13: " + getCheckMessage(MSG_KEY_BLOCK_EMPTY, "default"),
@@ -168,7 +168,7 @@ public class EmptyBlockCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testForbidDefaultWithoutStatement() throws Exception {
+  void forbidDefaultWithoutStatement() throws Exception {
     final String[] expected = {
       "15:30: " + getCheckMessage(MSG_KEY_BLOCK_NO_STATEMENT, "default"),
       "21:13: " + getCheckMessage(MSG_KEY_BLOCK_NO_STATEMENT, "default"),
@@ -184,7 +184,7 @@ public class EmptyBlockCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyBlockWithEmoji() throws Exception {
+  void emptyBlockWithEmoji() throws Exception {
     final String[] expected = {
       "15:12: " + getCheckMessage(MSG_KEY_BLOCK_EMPTY, "STATIC_INIT"),
       "25:27: " + getCheckMessage(MSG_KEY_BLOCK_EMPTY, "if"),
@@ -199,14 +199,14 @@ public class EmptyBlockCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationDefaultKeyword() throws Exception {
+  void annotationDefaultKeyword() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     final String path = getPath("InputEmptyBlockAnnotationDefaultKeyword.java");
     verifyWithInlineConfigParser(path, expected);
   }
 
   @Test
-  public void testEmptyBlockSwitchExpressions() throws Exception {
+  void emptyBlockSwitchExpressions() throws Exception {
     final String[] expected = {
       "17:30: " + getCheckMessage(MSG_KEY_BLOCK_NO_STATEMENT, "default"),
     };
@@ -215,7 +215,7 @@ public class EmptyBlockCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUppercaseProperty() throws Exception {
+  void uppercaseProperty() throws Exception {
     final String[] expected = {
       "16:30: " + getCheckMessage(MSG_KEY_BLOCK_EMPTY, "default"),
       "22:13: " + getCheckMessage(MSG_KEY_BLOCK_EMPTY, "default"),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/blocks/EmptyCatchBlockCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/blocks/EmptyCatchBlockCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class EmptyCatchBlockCheckTest extends AbstractModuleTestSupport {
+final class EmptyCatchBlockCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class EmptyCatchBlockCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final EmptyCatchBlockCheck checkObj = new EmptyCatchBlockCheck();
     final int[] expected = {TokenTypes.LITERAL_CATCH};
     assertWithMessage("Default required tokens are invalid")
@@ -43,7 +43,7 @@ public class EmptyCatchBlockCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "25:31: " + getCheckMessage(MSG_KEY_CATCH_BLOCK_EMPTY),
       "32:83: " + getCheckMessage(MSG_KEY_CATCH_BLOCK_EMPTY),
@@ -52,7 +52,7 @@ public class EmptyCatchBlockCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithUserSetValues() throws Exception {
+  void withUserSetValues() throws Exception {
     final String[] expected = {
       "26:31: " + getCheckMessage(MSG_KEY_CATCH_BLOCK_EMPTY),
       "54:78: " + getCheckMessage(MSG_KEY_CATCH_BLOCK_EMPTY),
@@ -67,7 +67,7 @@ public class EmptyCatchBlockCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLinesAreProperlySplitSystemIndependently() throws Exception {
+  void linesAreProperlySplitSystemIndependently() throws Exception {
     final String[] expected = {
       "25:31: " + getCheckMessage(MSG_KEY_CATCH_BLOCK_EMPTY),
       "53:78: " + getCheckMessage(MSG_KEY_CATCH_BLOCK_EMPTY),
@@ -88,7 +88,7 @@ public class EmptyCatchBlockCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final EmptyCatchBlockCheck constantNameCheckObj = new EmptyCatchBlockCheck();
     final int[] actual = constantNameCheckObj.getAcceptableTokens();
     final int[] expected = {TokenTypes.LITERAL_CATCH};
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/blocks/LeftCurlyCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/blocks/LeftCurlyCheckTest.java
@@ -30,7 +30,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
+final class LeftCurlyCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -42,13 +42,13 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
    * valueOf() is uncovered.
    */
   @Test
-  public void testLeftCurlyOptionValueOf() {
+  void leftCurlyOptionValueOf() {
     final LeftCurlyOption option = LeftCurlyOption.valueOf("NL");
     assertWithMessage("Invalid valueOf result").that(option).isEqualTo(LeftCurlyOption.NL);
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final LeftCurlyCheck checkObj = new LeftCurlyCheck();
     assertWithMessage("LeftCurlyCheck#getRequiredTokens should return empty array by default")
         .that(checkObj.getRequiredTokens())
@@ -56,7 +56,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "17:1: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 1),
       "19:5: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 5),
@@ -68,7 +68,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNl() throws Exception {
+  void nl() throws Exception {
     final String[] expected = {
       "36:14: " + getCheckMessage(MSG_KEY_LINE_NEW, "{", 14),
       "40:14: " + getCheckMessage(MSG_KEY_LINE_NEW, "{", 14),
@@ -85,7 +85,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNlow() throws Exception {
+  void nlow() throws Exception {
     final String[] expected = {
       "17:1: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 1),
       "19:5: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 5),
@@ -104,7 +104,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault2() throws Exception {
+  void default2() throws Exception {
     final String[] expected = {
       "17:1: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 1),
       "22:5: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 5),
@@ -126,7 +126,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNewline2() throws Exception {
+  void newline2() throws Exception {
     final String[] expected = {
       "19:44: " + getCheckMessage(MSG_KEY_LINE_NEW, "{", 44),
       "26:20: " + getCheckMessage(MSG_KEY_LINE_NEW, "{", 20),
@@ -141,7 +141,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault3() throws Exception {
+  void default3() throws Exception {
     final String[] expected = {
       "17:1: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 1),
       "20:5: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 5),
@@ -174,7 +174,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNewline3() throws Exception {
+  void newline3() throws Exception {
     final String[] expected = {
       "31:33: " + getCheckMessage(MSG_KEY_LINE_NEW, "{", 33),
       "96:19: " + getCheckMessage(MSG_KEY_LINE_NEW, "{", 19),
@@ -187,7 +187,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMissingBraces() throws Exception {
+  void missingBraces() throws Exception {
     final String[] expected = {
       "17:1: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 1),
       "20:5: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 5),
@@ -201,7 +201,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultWithAnnotations() throws Exception {
+  void defaultWithAnnotations() throws Exception {
     final String[] expected = {
       "23:1: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 1),
       "27:5: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 5),
@@ -215,7 +215,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNlWithAnnotations() throws Exception {
+  void nlWithAnnotations() throws Exception {
     final String[] expected = {
       "48:55: " + getCheckMessage(MSG_KEY_LINE_NEW, "{", 55),
       "51:41: " + getCheckMessage(MSG_KEY_LINE_NEW, "{", 41),
@@ -226,7 +226,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNlowWithAnnotations() throws Exception {
+  void nlowWithAnnotations() throws Exception {
     final String[] expected = {
       "23:1: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 1),
       "27:5: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 5),
@@ -239,7 +239,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLineBreakAfter() throws Exception {
+  void lineBreakAfter() throws Exception {
     final String[] expected = {
       "22:1: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 1),
       "25:5: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 5),
@@ -262,7 +262,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreEnumsOptionTrue() throws Exception {
+  void ignoreEnumsOptionTrue() throws Exception {
     final String[] expectedWhileTrue = {
       "21:44: " + getCheckMessage(MSG_KEY_LINE_BREAK_AFTER, "{", 44),
     };
@@ -271,7 +271,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreEnumsOptionFalse() throws Exception {
+  void ignoreEnumsOptionFalse() throws Exception {
     final String[] expectedWhileFalse = {
       "17:17: " + getCheckMessage(MSG_KEY_LINE_BREAK_AFTER, "{", 17),
       "21:44: " + getCheckMessage(MSG_KEY_LINE_BREAK_AFTER, "{", 44),
@@ -281,7 +281,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultLambda() throws Exception {
+  void defaultLambda() throws Exception {
     final String[] expected = {
       "17:1: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 1),
       "24:32: " + getCheckMessage(MSG_KEY_LINE_BREAK_AFTER, "{", 32),
@@ -291,7 +291,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNewLineOptionWithLambda() throws Exception {
+  void newLineOptionWithLambda() throws Exception {
     final String[] expected = {
       "18:32: " + getCheckMessage(MSG_KEY_LINE_NEW, "{", 32),
       "24:32: " + getCheckMessage(MSG_KEY_LINE_NEW, "{", 32),
@@ -301,7 +301,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEolSwitch() throws Exception {
+  void eolSwitch() throws Exception {
     final String[] expected = {
       "22:13: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 13),
       "26:13: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 13),
@@ -313,7 +313,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNlSwitch() throws Exception {
+  void nlSwitch() throws Exception {
     final String[] expected = {
       "24:21: " + getCheckMessage(MSG_KEY_LINE_NEW, "{", 21),
       "56:14: " + getCheckMessage(MSG_KEY_LINE_NEW, "{", 14),
@@ -322,7 +322,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNlowSwitch() throws Exception {
+  void nlowSwitch() throws Exception {
     final String[] expected = {
       "22:13: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 13),
     };
@@ -330,7 +330,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLeftCurlySwitchExpressions() throws Exception {
+  void leftCurlySwitchExpressions() throws Exception {
     final String[] expected = {
       "20:9: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 9),
       "22:17: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 17),
@@ -348,7 +348,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLeftCurlySwitchExpressionsNewLine() throws Exception {
+  void leftCurlySwitchExpressionsNewLine() throws Exception {
 
     final String[] expected = {
       "17:57: " + getCheckMessage(MSG_KEY_LINE_NEW, "{", 57),
@@ -361,7 +361,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final LeftCurlyCheck check = new LeftCurlyCheck();
     final int[] actual = check.getAcceptableTokens();
     final int[] expected = {
@@ -394,13 +394,13 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFirstLine() throws Exception {
+  void firstLine() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputLeftCurlyTestFirstLine.java"), expected);
   }
 
   @Test
-  public void testCoverageIncrease() throws Exception {
+  void coverageIncrease() throws Exception {
     final String[] expected = {
       "21:5: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 5),
       "30:5: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 5),
@@ -416,7 +416,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLeftCurlyRecordsAndCompactCtors() throws Exception {
+  void leftCurlyRecordsAndCompactCtors() throws Exception {
     final String[] expected = {
       "22:5: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 5),
       "24:9: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 9),
@@ -430,7 +430,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLeftCurlyWithEmoji() throws Exception {
+  void leftCurlyWithEmoji() throws Exception {
     final String[] expected = {
       "17:32: " + getCheckMessage(MSG_KEY_LINE_BREAK_AFTER, "{", 32),
       "37:9: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 9),
@@ -448,7 +448,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLeftCurlyWithEmojiNewLine() throws Exception {
+  void leftCurlyWithEmojiNewLine() throws Exception {
     final String[] expected = {
       "18:32: " + getCheckMessage(MSG_KEY_LINE_NEW, "{", 32),
       "20:27: " + getCheckMessage(MSG_KEY_LINE_NEW, "{", 27),
@@ -468,7 +468,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidOption() throws Exception {
+  void invalidOption() throws Exception {
 
     try {
       final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -487,7 +487,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTrimOptionProperty() throws Exception {
+  void trimOptionProperty() throws Exception {
     final String[] expected = {
       "13:12: " + getCheckMessage(MSG_KEY_LINE_NEW, "{", 12),
       "20:16: " + getCheckMessage(MSG_KEY_LINE_NEW, "{", 16),
@@ -496,7 +496,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testForEnumConstantDef() throws Exception {
+  void forEnumConstantDef() throws Exception {
     final String[] expected = {
       "14:5: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 5),
       "19:5: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 5),
@@ -505,7 +505,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void commentBeforeLeftCurly() throws Exception {
+  void commentBeforeLeftCurly() throws Exception {
     final String[] expected = {
       "32:5: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 5),
     };
@@ -513,7 +513,7 @@ public class LeftCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void commentBeforeLeftCurly2() throws Exception {
+  void commentBeforeLeftCurly2() throws Exception {
     final String[] expected = {
       "54:9: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 9),
       "66:29: " + getCheckMessage(MSG_KEY_LINE_BREAK_AFTER, "{", 29),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/blocks/NeedBracesCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/blocks/NeedBracesCheckTest.java
@@ -25,7 +25,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class NeedBracesCheckTest extends AbstractModuleTestSupport {
+final class NeedBracesCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class NeedBracesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIt() throws Exception {
+  void it() throws Exception {
     final String[] expected = {
       "30:9: " + getCheckMessage(MSG_KEY_NEED_BRACES, "do"),
       "42:9: " + getCheckMessage(MSG_KEY_NEED_BRACES, "while"),
@@ -63,7 +63,7 @@ public class NeedBracesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testItWithAllowsOn() throws Exception {
+  void itWithAllowsOn() throws Exception {
     final String[] expected = {
       "44:9: " + getCheckMessage(MSG_KEY_NEED_BRACES, "while"),
       "47:13: " + getCheckMessage(MSG_KEY_NEED_BRACES, "if"),
@@ -88,7 +88,7 @@ public class NeedBracesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSingleLineStatements() throws Exception {
+  void singleLineStatements() throws Exception {
     final String[] expected = {
       "32:9: " + getCheckMessage(MSG_KEY_NEED_BRACES, "if"),
       "38:43: " + getCheckMessage(MSG_KEY_NEED_BRACES, "if"),
@@ -106,7 +106,7 @@ public class NeedBracesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSingleLineLambda() throws Exception {
+  void singleLineLambda() throws Exception {
     final String[] expected = {
       "16:29: " + getCheckMessage(MSG_KEY_NEED_BRACES, "->"),
       "19:22: " + getCheckMessage(MSG_KEY_NEED_BRACES, "->"),
@@ -117,7 +117,7 @@ public class NeedBracesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDoNotAllowSingleLineLambda() throws Exception {
+  void doNotAllowSingleLineLambda() throws Exception {
     final String[] expected = {
       "14:28: " + getCheckMessage(MSG_KEY_NEED_BRACES, "->"),
       "15:29: " + getCheckMessage(MSG_KEY_NEED_BRACES, "->"),
@@ -131,7 +131,7 @@ public class NeedBracesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSingleLineCaseDefault() throws Exception {
+  void singleLineCaseDefault() throws Exception {
     final String[] expected = {
       "81:13: " + getCheckMessage(MSG_KEY_NEED_BRACES, "case"),
       "84:13: " + getCheckMessage(MSG_KEY_NEED_BRACES, "case"),
@@ -143,14 +143,14 @@ public class NeedBracesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSingleLineCaseDefault2() throws Exception {
+  void singleLineCaseDefault2() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputNeedBracesTestSingleLineCaseDefault2.java"), expected);
   }
 
   @Test
-  public void testSingleLineCaseDefaultNoSingleLine() throws Exception {
+  void singleLineCaseDefaultNoSingleLine() throws Exception {
     final String[] expected = {
       "18:9: " + getCheckMessage(MSG_KEY_NEED_BRACES, "case"),
       "19:9: " + getCheckMessage(MSG_KEY_NEED_BRACES, "case"),
@@ -164,13 +164,13 @@ public class NeedBracesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCycles() throws Exception {
+  void cycles() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputNeedBracesTestCycles.java"), expected);
   }
 
   @Test
-  public void testConditions() throws Exception {
+  void conditions() throws Exception {
     final String[] expected = {
       "50:9: " + getCheckMessage(MSG_KEY_NEED_BRACES, "case"),
       "53:9: " + getCheckMessage(MSG_KEY_NEED_BRACES, "case"),
@@ -180,7 +180,7 @@ public class NeedBracesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowEmptyLoopBodyTrue() throws Exception {
+  void allowEmptyLoopBodyTrue() throws Exception {
     final String[] expected = {
       "106:9: " + getCheckMessage(MSG_KEY_NEED_BRACES, "if"),
     };
@@ -188,7 +188,7 @@ public class NeedBracesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowEmptyLoopBodyFalse() throws Exception {
+  void allowEmptyLoopBodyFalse() throws Exception {
     final String[] expected = {
       "19:9: " + getCheckMessage(MSG_KEY_NEED_BRACES, "while"),
       "23:9: " + getCheckMessage(MSG_KEY_NEED_BRACES, "while"),
@@ -212,14 +212,14 @@ public class NeedBracesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptySingleLineDefaultStmt() throws Exception {
+  void emptySingleLineDefaultStmt() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputNeedBracesEmptySingleLineDefaultStmt.java"), expected);
   }
 
   @Test
-  public void testNeedBracesSwitchExpressionNoSingleLine() throws Exception {
+  void needBracesSwitchExpressionNoSingleLine() throws Exception {
     final String[] expected = {
       "16:13: " + getCheckMessage(MSG_KEY_NEED_BRACES, "case"),
       "18:47: " + getCheckMessage(MSG_KEY_NEED_BRACES, "->"),
@@ -243,7 +243,7 @@ public class NeedBracesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNeedBracesSwitchExpression() throws Exception {
+  void needBracesSwitchExpression() throws Exception {
     final String[] expected = {
       "16:13: " + getCheckMessage(MSG_KEY_NEED_BRACES, "case"),
       "18:47: " + getCheckMessage(MSG_KEY_NEED_BRACES, "->"),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/blocks/RightCurlyCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/blocks/RightCurlyCheckTest.java
@@ -29,7 +29,7 @@ import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class RightCurlyCheckTest extends AbstractModuleTestSupport {
+final class RightCurlyCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -41,13 +41,13 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
    * valueOf() is uncovered.
    */
   @Test
-  public void testRightCurlyOptionValueOf() {
+  void rightCurlyOptionValueOf() {
     final RightCurlyOption option = RightCurlyOption.valueOf("ALONE");
     assertWithMessage("Invalid valueOf result").that(option).isEqualTo(RightCurlyOption.ALONE);
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "25:17: " + getCheckMessage(MSG_KEY_LINE_SAME, "}", 17),
       "28:17: " + getCheckMessage(MSG_KEY_LINE_SAME, "}", 17),
@@ -59,7 +59,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSame() throws Exception {
+  void same() throws Exception {
     final String[] expected = {
       "26:17: " + getCheckMessage(MSG_KEY_LINE_SAME, "}", 17),
       "29:17: " + getCheckMessage(MSG_KEY_LINE_SAME, "}", 17),
@@ -74,19 +74,19 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSameOmitOneLiners() throws Exception {
+  void sameOmitOneLiners() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRightCurlyTestSameOmitOneLiners.java"), expected);
   }
 
   @Test
-  public void testSameDoesNotComplainForNonMultilineConstructs() throws Exception {
+  void sameDoesNotComplainForNonMultilineConstructs() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRightCurlyTestSame.java"), expected);
   }
 
   @Test
-  public void testAlone() throws Exception {
+  void alone() throws Exception {
     final String[] expected = {
       "57:13: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 13),
       "94:27: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 27),
@@ -103,7 +103,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNewLine() throws Exception {
+  void newLine() throws Exception {
     final String[] expected = {
       "86:5: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 5),
       "111:5: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 5),
@@ -126,7 +126,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testShouldStartLine2() throws Exception {
+  void shouldStartLine2() throws Exception {
     final String[] expected = {
       "86:5: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 5),
       "111:5: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 5),
@@ -144,7 +144,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testForceLineBreakBefore() throws Exception {
+  void forceLineBreakBefore() throws Exception {
     final String[] expected = {
       "38:43: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 43),
       "41:17: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 17),
@@ -156,20 +156,20 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testForceLineBreakBefore2() throws Exception {
+  void forceLineBreakBefore2() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputRightCurlyTestForceLineBreakBefore2.java"), expected);
   }
 
   @Test
-  public void testNullPointerException() throws Exception {
+  void nullPointerException() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRightCurlyTestNullPointerException.java"), expected);
   }
 
   @Test
-  public void testWithAnnotations() throws Exception {
+  void withAnnotations() throws Exception {
     final String[] expected = {
       "18:77: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 77),
       "21:65: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 65),
@@ -246,7 +246,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAloneOrSingleLine() throws Exception {
+  void aloneOrSingleLine() throws Exception {
     final String[] expected = {
       "70:26: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 26),
       "84:42: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 42),
@@ -293,7 +293,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCatchWithoutFinally() throws Exception {
+  void catchWithoutFinally() throws Exception {
     final String[] expected = {
       "19:9: " + getCheckMessage(MSG_KEY_LINE_SAME, "}", 9),
     };
@@ -301,7 +301,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSingleLineClass() throws Exception {
+  void singleLineClass() throws Exception {
     final String[] expected = {
       "29:56: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 56),
     };
@@ -309,7 +309,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidOption() throws Exception {
+  void invalidOption() throws Exception {
 
     try {
       final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -328,7 +328,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRightCurlySameAndLiteralDo() throws Exception {
+  void rightCurlySameAndLiteralDo() throws Exception {
     final String[] expected = {
       "70:9: " + getCheckMessage(MSG_KEY_LINE_SAME, "}", 9),
       "75:13: " + getCheckMessage(MSG_KEY_LINE_SAME, "}", 13),
@@ -338,7 +338,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTryWithResourceSame() throws Exception {
+  void tryWithResourceSame() throws Exception {
     final String[] expected = {
       "19:9: " + getCheckMessage(MSG_KEY_LINE_SAME, "}", 9),
       "33:67: " + getCheckMessage(MSG_KEY_LINE_SAME, "}", 67),
@@ -349,7 +349,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTryWithResourceAlone() throws Exception {
+  void tryWithResourceAlone() throws Exception {
     final String[] expected = {
       "27:9: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 9),
       "33:67: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 67),
@@ -364,7 +364,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTryWithResourceAloneSingle() throws Exception {
+  void tryWithResourceAloneSingle() throws Exception {
     final String[] expected = {
       "27:9: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 9),
       "36:64: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 64),
@@ -376,7 +376,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBracePolicyAloneAndSinglelineIfBlocks() throws Exception {
+  void bracePolicyAloneAndSinglelineIfBlocks() throws Exception {
     final String[] expected = {
       "13:32: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 32),
       "15:45: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 45),
@@ -386,26 +386,26 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRightCurlyIsAloneLambda() throws Exception {
+  void rightCurlyIsAloneLambda() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRightCurlyTestIsAloneLambda.java"), expected);
   }
 
   @Test
-  public void testRightCurlyIsAloneOrSinglelineLambda() throws Exception {
+  void rightCurlyIsAloneOrSinglelineLambda() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputRightCurlyTestIsAloneOrSinglelineLambda.java"), expected);
   }
 
   @Test
-  public void testRightCurlyIsSameLambda() throws Exception {
+  void rightCurlyIsSameLambda() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRightCurlyTestIsSameLambda.java"), expected);
   }
 
   @Test
-  public void testOptionAlone() throws Exception {
+  void optionAlone() throws Exception {
     final String[] expected = {
       "16:15: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 15),
       "17:21: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 21),
@@ -433,7 +433,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOptionAloneOrSingleLine() throws Exception {
+  void optionAloneOrSingleLine() throws Exception {
     final String[] expected = {
       "21:26: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 26),
       "30:37: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 37),
@@ -450,7 +450,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBlocksEndingWithSemiOptionSame() throws Exception {
+  void blocksEndingWithSemiOptionSame() throws Exception {
     final String[] expected = {
       "16:5: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 5),
       "21:5: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 5),
@@ -471,7 +471,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBlocksEndingWithSemiOptionAlone() throws Exception {
+  void blocksEndingWithSemiOptionAlone() throws Exception {
     final String[] expected = {
       "13:31: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 31),
       "16:5: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 5),
@@ -499,7 +499,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBlocksEndingWithSemiOptionAloneOrSingleLine() throws Exception {
+  void blocksEndingWithSemiOptionAloneOrSingleLine() throws Exception {
     final String[] expected = {
       "16:5: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 5),
       "21:5: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 5),
@@ -520,7 +520,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNewTokensAlone() throws Exception {
+  void newTokensAlone() throws Exception {
     final String[] expected = {
       "13:19: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 19),
       "16:20: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 20),
@@ -530,7 +530,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNewTokensAloneOrSingleLine() throws Exception {
+  void newTokensAloneOrSingleLine() throws Exception {
     final String[] expected = {
       "16:20: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 20),
     };
@@ -539,7 +539,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNewTokensSame() throws Exception {
+  void newTokensSame() throws Exception {
     final String[] expected = {
       "16:20: " + getCheckMessage(MSG_KEY_LINE_BREAK_BEFORE, "}", 20),
     };
@@ -547,7 +547,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRightCurlyDoubleBrace() throws Exception {
+  void rightCurlyDoubleBrace() throws Exception {
     final String[] expected = {
       "14:1: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 1),
       "14:2: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 2),
@@ -556,13 +556,13 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRightCurlyEmptyOnSingleLine() throws Exception {
+  void rightCurlyEmptyOnSingleLine() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRightCurlyTestEmptyOnSingleLine.java"), expected);
   }
 
   @Test
-  public void testRightCurlyEndOfFile() throws Exception {
+  void rightCurlyEndOfFile() throws Exception {
     final String[] expected = {
       "16:2: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 2),
       "16:3: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 3),
@@ -571,7 +571,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRightCurlyRecordsAndCompactCtors() throws Exception {
+  void rightCurlyRecordsAndCompactCtors() throws Exception {
     final String[] expected = {
       "23:9: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 9),
       "23:11: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 11),
@@ -585,7 +585,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRightCurlyWithEmoji() throws Exception {
+  void rightCurlyWithEmoji() throws Exception {
     final String[] expected = {
       "24:13: " + getCheckMessage(MSG_KEY_LINE_SAME, "}", 13),
       "28:13: " + getCheckMessage(MSG_KEY_LINE_SAME, "}", 13),
@@ -598,7 +598,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRightCurlyWithEmojiAloneOrSingleLine() throws Exception {
+  void rightCurlyWithEmojiAloneOrSingleLine() throws Exception {
     final String[] expected = {
       "24:38: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 38),
       "30:43: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 43),
@@ -611,7 +611,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUppercaseOptionProperty() throws Exception {
+  void uppercaseOptionProperty() throws Exception {
     final String[] expected = {
       "16:46: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 46),
       "21:35: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 35),
@@ -621,7 +621,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRightCurlyWithIfElseAlone() throws Exception {
+  void rightCurlyWithIfElseAlone() throws Exception {
     final String[] expected = {
       "19:12: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 12),
       "27:9: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 9),
@@ -630,7 +630,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSwitchCase() throws Exception {
+  void switchCase() throws Exception {
     final String[] expected = {
       "20:24: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 24),
       "27:27: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 27),
@@ -644,7 +644,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSwitchCase2() throws Exception {
+  void switchCase2() throws Exception {
     final String[] expected = {
       "20:24: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 24),
       "27:27: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 27),
@@ -654,7 +654,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSwitchCase3() throws Exception {
+  void switchCase3() throws Exception {
     final String[] expected = {
       "15:22: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 22),
       "17:9: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 9),
@@ -677,7 +677,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSwitchCase4() throws Exception {
+  void switchCase4() throws Exception {
     final String[] expected = {
       "17:9: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 9),
       "19:36: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 36),
@@ -693,7 +693,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSwitchCase5() throws Exception {
+  void switchCase5() throws Exception {
     final String[] expected = {
       "17:9: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 9),
       "19:36: " + getCheckMessage(MSG_KEY_LINE_BREAK_BEFORE, "}", 36),
@@ -710,7 +710,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSwitchExpression() throws Exception {
+  void switchExpression() throws Exception {
     final String[] expected = {
       "48:5: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 5),
       "56:5: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 5),
@@ -721,7 +721,7 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSwitchExpression2() throws Exception {
+  void switchExpression2() throws Exception {
     final String[] expected = {
       "46:5: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 5),
       "54:5: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 5),
@@ -733,14 +733,14 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSwitchExpression3() throws Exception {
+  void switchExpression3() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getNonCompilablePath("InputRightCurlyTestSwitchExpression3.java"), expected);
   }
 
   @Test
-  public void testSwitchExpression4() throws Exception {
+  void switchExpression4() throws Exception {
     final String[] expected = {
       "117:28: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 28),
     };
@@ -749,14 +749,14 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSwitchExpression5() throws Exception {
+  void switchExpression5() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getNonCompilablePath("InputRightCurlyTestSwitchExpression5.java"), expected);
   }
 
   @Test
-  public void testSwitchWithComment() throws Exception {
+  void switchWithComment() throws Exception {
     final String[] expected = {
       "16:66: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 66),
       "23:61: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 61),
@@ -770,14 +770,14 @@ public class RightCurlyCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSwitchExpression6() throws Exception {
+  void switchExpression6() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getNonCompilablePath("InputRightCurlyTestSwitchExpression6.java"), expected);
   }
 
   @Test
-  public void testSwitchExpression7() throws Exception {
+  void switchExpression7() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getNonCompilablePath("InputRightCurlyTestSwitchExpression7.java"), expected);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/ArrayTrailingCommaCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/ArrayTrailingCommaCheckTest.java
@@ -25,7 +25,7 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.ArrayTrailingCommaCh
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class ArrayTrailingCommaCheckTest extends AbstractModuleTestSupport {
+final class ArrayTrailingCommaCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class ArrayTrailingCommaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "23:9: " + getCheckMessage(MSG_KEY),
       "43:9: " + getCheckMessage(MSG_KEY),
@@ -44,7 +44,7 @@ public class ArrayTrailingCommaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final ArrayTrailingCommaCheck check = new ArrayTrailingCommaCheck();
     assertWithMessage("Invalid acceptable tokens").that(check.getAcceptableTokens()).isNotNull();
     assertWithMessage("Invalid default tokens").that(check.getDefaultTokens()).isNotNull();
@@ -52,7 +52,7 @@ public class ArrayTrailingCommaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAlwaysDemandTrailingComma() throws Exception {
+  void alwaysDemandTrailingComma() throws Exception {
     final String[] expected = {
       "15:26: " + getCheckMessage(MSG_KEY),
       "22:29: " + getCheckMessage(MSG_KEY),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/AvoidDoubleBraceInitializationCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/AvoidDoubleBraceInitializationCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class AvoidDoubleBraceInitializationCheckTest extends AbstractModuleTestSupport {
+final class AvoidDoubleBraceInitializationCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class AvoidDoubleBraceInitializationCheckTest extends AbstractModuleTestS
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "14:53: " + getCheckMessage(MSG_KEY),
       "19:40: " + getCheckMessage(MSG_KEY),
@@ -54,7 +54,7 @@ public class AvoidDoubleBraceInitializationCheckTest extends AbstractModuleTestS
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final AvoidDoubleBraceInitializationCheck check = new AvoidDoubleBraceInitializationCheck();
     final int[] expected = {
       TokenTypes.OBJBLOCK,
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/AvoidInlineConditionalsCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/AvoidInlineConditionalsCheckTest.java
@@ -25,7 +25,7 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.AvoidInlineCondition
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class AvoidInlineConditionalsCheckTest extends AbstractModuleTestSupport {
+final class AvoidInlineConditionalsCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class AvoidInlineConditionalsCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "34:29: " + getCheckMessage(MSG_KEY),
       "35:20: " + getCheckMessage(MSG_KEY),
@@ -43,7 +43,7 @@ public class AvoidInlineConditionalsCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final AvoidInlineConditionalsCheck check = new AvoidInlineConditionalsCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/AvoidNoArgumentSuperConstructorCallCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/AvoidNoArgumentSuperConstructorCallCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class AvoidNoArgumentSuperConstructorCallCheckTest extends AbstractModuleTestSupport {
+final class AvoidNoArgumentSuperConstructorCallCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class AvoidNoArgumentSuperConstructorCallCheckTest extends AbstractModule
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
 
     final String[] expected = {
       "12:9: " + getCheckMessage(MSG_CTOR),
@@ -47,7 +47,7 @@ public class AvoidNoArgumentSuperConstructorCallCheckTest extends AbstractModule
   }
 
   @Test
-  public void testTokens() {
+  void tokens() {
     final AvoidNoArgumentSuperConstructorCallCheck check =
         new AvoidNoArgumentSuperConstructorCallCheck();
     final int[] expected = {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/CovariantEqualsCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/CovariantEqualsCheckTest.java
@@ -25,7 +25,7 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.CovariantEqualsCheck
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class CovariantEqualsCheckTest extends AbstractModuleTestSupport {
+final class CovariantEqualsCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class CovariantEqualsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "17:24: " + getCheckMessage(MSG_KEY),
       "36:20: " + getCheckMessage(MSG_KEY),
@@ -46,7 +46,7 @@ public class CovariantEqualsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCovariantEqualsRecords() throws Exception {
+  void covariantEqualsRecords() throws Exception {
     final String[] expected = {
       "13:24: " + getCheckMessage(MSG_KEY), "29:28: " + getCheckMessage(MSG_KEY),
     };
@@ -55,7 +55,7 @@ public class CovariantEqualsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final CovariantEqualsCheck check = new CovariantEqualsCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/DeclarationOrderCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/DeclarationOrderCheckTest.java
@@ -33,7 +33,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.util.SortedSet;
 import org.junit.jupiter.api.Test;
 
-public class DeclarationOrderCheckTest extends AbstractModuleTestSupport {
+final class DeclarationOrderCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -41,7 +41,7 @@ public class DeclarationOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
 
     final String[] expected = {
       "16:5: " + getCheckMessage(MSG_ACCESS),
@@ -70,7 +70,7 @@ public class DeclarationOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOnlyConstructors() throws Exception {
+  void onlyConstructors() throws Exception {
 
     final String[] expected = {
       "53:9: " + getCheckMessage(MSG_STATIC),
@@ -85,7 +85,7 @@ public class DeclarationOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOnlyModifiers() throws Exception {
+  void onlyModifiers() throws Exception {
 
     final String[] expected = {
       "16:5: " + getCheckMessage(MSG_ACCESS),
@@ -112,7 +112,7 @@ public class DeclarationOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final DeclarationOrderCheck check = new DeclarationOrderCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
@@ -126,7 +126,7 @@ public class DeclarationOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testParents() {
+  void parents() {
     final DetailAstImpl parent = new DetailAstImpl();
     parent.setType(TokenTypes.STATIC_INIT);
     final DetailAstImpl method = new DetailAstImpl();
@@ -150,7 +150,7 @@ public class DeclarationOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testImproperToken() {
+  void improperToken() {
     final DetailAstImpl parent = new DetailAstImpl();
     parent.setType(TokenTypes.STATIC_INIT);
     final DetailAstImpl array = new DetailAstImpl();
@@ -166,7 +166,7 @@ public class DeclarationOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testForwardReference() throws Exception {
+  void forwardReference() throws Exception {
     final String[] expected = {
       "20:5: " + getCheckMessage(MSG_ACCESS),
       "21:5: " + getCheckMessage(MSG_ACCESS),
@@ -182,7 +182,7 @@ public class DeclarationOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDeclarationOrderRecordsAndCompactCtors() throws Exception {
+  void declarationOrderRecordsAndCompactCtors() throws Exception {
     final String[] expected = {
       "21:9: " + getCheckMessage(MSG_CONSTRUCTOR),
       "24:9: " + getCheckMessage(MSG_STATIC),
@@ -195,7 +195,7 @@ public class DeclarationOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDeclarationOrderInterfaceMemberScopeIsPublic() throws Exception {
+  void declarationOrderInterfaceMemberScopeIsPublic() throws Exception {
     final String[] expected = {
       "21:3: " + getCheckMessage(MSG_STATIC),
     };
@@ -204,7 +204,7 @@ public class DeclarationOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testVariableAccess() throws Exception {
+  void variableAccess() throws Exception {
     final String[] expected = {
       "23:5: " + getCheckMessage(MSG_ACCESS),
     };
@@ -212,7 +212,7 @@ public class DeclarationOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAvoidDuplicatesForStaticFinalFields() throws Exception {
+  void avoidDuplicatesForStaticFinalFields() throws Exception {
     final String[] expected = {
       "14:5: " + getCheckMessage(MSG_STATIC),
     };
@@ -221,7 +221,7 @@ public class DeclarationOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test() throws Exception {
+  void test() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputDeclarationOrder2.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/DefaultComesLastCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/DefaultComesLastCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class DefaultComesLastCheckTest extends AbstractModuleTestSupport {
+final class DefaultComesLastCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class DefaultComesLastCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSkipIfLastAndSharedWithCase() throws Exception {
+  void skipIfLastAndSharedWithCase() throws Exception {
     final String[] expected = {
       "23:13: " + getCheckMessage(MSG_KEY_SKIP_IF_LAST_AND_SHARED_WITH_CASE),
       "31:13: " + getCheckMessage(MSG_KEY_SKIP_IF_LAST_AND_SHARED_WITH_CASE),
@@ -52,7 +52,7 @@ public class DefaultComesLastCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "31:9: " + getCheckMessage(MSG_KEY),
       "38:24: " + getCheckMessage(MSG_KEY),
@@ -73,14 +73,14 @@ public class DefaultComesLastCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultMethodsInJava8() throws Exception {
+  void defaultMethodsInJava8() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputDefaultComesLastDefaultMethodsInInterface.java"), expected);
   }
 
   @Test
-  public void testDefaultComesLastSwitchExpressions() throws Exception {
+  void defaultComesLastSwitchExpressions() throws Exception {
     final String[] expected = {
       "16:13: " + getCheckMessage(MSG_KEY),
       "32:13: " + getCheckMessage(MSG_KEY),
@@ -91,7 +91,7 @@ public class DefaultComesLastCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultComesLastSwitchExpressionsSkipIfLast() throws Exception {
+  void defaultComesLastSwitchExpressionsSkipIfLast() throws Exception {
 
     final String[] expected = {
       "33:13: " + getCheckMessage(MSG_KEY), "48:13: " + getCheckMessage(MSG_KEY),
@@ -101,7 +101,7 @@ public class DefaultComesLastCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final DefaultComesLastCheck check = new DefaultComesLastCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
@@ -115,7 +115,7 @@ public class DefaultComesLastCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultMethodsInJava8Interface2() throws Exception {
+  void defaultMethodsInJava8Interface2() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputDefaultComesLastDefaultMethodsInInterface2.java"), expected);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/EmptyStatementCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/EmptyStatementCheckTest.java
@@ -25,7 +25,7 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.EmptyStatementCheck.
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class EmptyStatementCheckTest extends AbstractModuleTestSupport {
+final class EmptyStatementCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class EmptyStatementCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyStatements() throws Exception {
+  void emptyStatements() throws Exception {
     final String[] expected = {
       "18:7: " + getCheckMessage(MSG_KEY),
       "23:7: " + getCheckMessage(MSG_KEY),
@@ -57,7 +57,7 @@ public class EmptyStatementCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final EmptyStatementCheck check = new EmptyStatementCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/EqualsAvoidNullCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/EqualsAvoidNullCheckTest.java
@@ -26,7 +26,7 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.EqualsAvoidNullCheck
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class EqualsAvoidNullCheckTest extends AbstractModuleTestSupport {
+final class EqualsAvoidNullCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class EqualsAvoidNullCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEqualsWithDefault() throws Exception {
+  void equalsWithDefault() throws Exception {
 
     final String[] expected = {
       "44:27: " + getCheckMessage(MSG_EQUALS_IGNORE_CASE_AVOID_NULL),
@@ -97,7 +97,7 @@ public class EqualsAvoidNullCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEqualsWithoutEqualsIgnoreCase() throws Exception {
+  void equalsWithoutEqualsIgnoreCase() throws Exception {
 
     final String[] expected = {
       "245:21: " + getCheckMessage(MSG_EQUALS_AVOID_NULL),
@@ -148,7 +148,7 @@ public class EqualsAvoidNullCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEqualsOnTheSameLine() throws Exception {
+  void equalsOnTheSameLine() throws Exception {
 
     final String[] expected = {
       "14:28: " + getCheckMessage(MSG_EQUALS_AVOID_NULL),
@@ -158,7 +158,7 @@ public class EqualsAvoidNullCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEqualsNested() throws Exception {
+  void equalsNested() throws Exception {
 
     final String[] expected = {
       "25:34: " + getCheckMessage(MSG_EQUALS_IGNORE_CASE_AVOID_NULL),
@@ -174,7 +174,7 @@ public class EqualsAvoidNullCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEqualsSuperClass() throws Exception {
+  void equalsSuperClass() throws Exception {
 
     final String[] expected = {
       "23:35: " + getCheckMessage(MSG_EQUALS_AVOID_NULL),
@@ -183,7 +183,7 @@ public class EqualsAvoidNullCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInputEqualsAvoidNullEnhancedInstanceof() throws Exception {
+  void inputEqualsAvoidNullEnhancedInstanceof() throws Exception {
 
     final String[] expected = {
       "15:45: " + getCheckMessage(MSG_EQUALS_AVOID_NULL),
@@ -198,7 +198,7 @@ public class EqualsAvoidNullCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMisc() throws Exception {
+  void misc() throws Exception {
 
     final String[] expected = {
       "20:17: " + getCheckMessage(MSG_EQUALS_AVOID_NULL),
@@ -207,7 +207,7 @@ public class EqualsAvoidNullCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRecordsAndCompactCtors() throws Exception {
+  void recordsAndCompactCtors() throws Exception {
 
     final String[] expected = {
       "15:23: " + getCheckMessage(MSG_EQUALS_AVOID_NULL),
@@ -221,7 +221,7 @@ public class EqualsAvoidNullCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEqualsAvoidNullTextBlocks() throws Exception {
+  void equalsAvoidNullTextBlocks() throws Exception {
 
     final String[] expected = {
       "13:24: " + getCheckMessage(MSG_EQUALS_AVOID_NULL),
@@ -235,7 +235,7 @@ public class EqualsAvoidNullCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final EqualsAvoidNullCheck check = new EqualsAvoidNullCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
@@ -249,7 +249,7 @@ public class EqualsAvoidNullCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEqualAvoidNull() throws Exception {
+  void equalAvoidNull() throws Exception {
     final String[] expected = {
       "12:17: " + getCheckMessage(MSG_EQUALS_AVOID_NULL),
       "13:17: " + getCheckMessage(MSG_EQUALS_AVOID_NULL),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/EqualsHashCodeCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/EqualsHashCodeCheckTest.java
@@ -23,17 +23,17 @@ import static com.google.common.truth.Truth.assertWithMessage;
 import static com.puppycrawl.tools.checkstyle.checks.coding.EqualsHashCodeCheck.MSG_KEY_EQUALS;
 import static com.puppycrawl.tools.checkstyle.checks.coding.EqualsHashCodeCheck.MSG_KEY_HASHCODE;
 
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class EqualsHashCodeCheckTest extends AbstractModuleTestSupport {
+final class EqualsHashCodeCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -41,7 +41,7 @@ public class EqualsHashCodeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSemantic() throws Exception {
+  void semantic() throws Exception {
     final String[] expected = {
       "96:13: " + getCheckMessage(MSG_KEY_HASHCODE),
     };
@@ -49,7 +49,7 @@ public class EqualsHashCodeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoEquals() throws Exception {
+  void noEquals() throws Exception {
     final String[] expected = {
       "10:5: " + getCheckMessage(MSG_KEY_EQUALS),
     };
@@ -57,19 +57,19 @@ public class EqualsHashCodeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBooleanMethods() throws Exception {
+  void booleanMethods() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputEqualsHashCode.java"), expected);
   }
 
   @Test
-  public void testMultipleInputs() throws Exception {
+  void multipleInputs() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(EqualsHashCodeCheck.class);
 
     final List<String> expectedFirstInputErrors =
-        Collections.singletonList("10:5: " + getCheckMessage(MSG_KEY_EQUALS));
+        ImmutableList.of("10:5: " + getCheckMessage(MSG_KEY_EQUALS));
     final List<String> expectedSecondInputErrors =
-        Collections.singletonList("96:13: " + getCheckMessage(MSG_KEY_HASHCODE));
+        ImmutableList.of("96:13: " + getCheckMessage(MSG_KEY_HASHCODE));
     final List<String> expectedThirdInputErrors = Arrays.asList(CommonUtil.EMPTY_STRING_ARRAY);
 
     final String firstInput = getPath("InputEqualsHashCodeNoEquals.java");
@@ -90,7 +90,7 @@ public class EqualsHashCodeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEqualsParameter() throws Exception {
+  void equalsParameter() throws Exception {
     final String[] expected = {
       "16:9: " + getCheckMessage(MSG_KEY_EQUALS),
       "24:9: " + getCheckMessage(MSG_KEY_HASHCODE),
@@ -106,7 +106,7 @@ public class EqualsHashCodeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final EqualsHashCodeCheck check = new EqualsHashCodeCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/ExplicitInitializationCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/ExplicitInitializationCheckTest.java
@@ -25,7 +25,7 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.ExplicitInitializati
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class ExplicitInitializationCheckTest extends AbstractModuleTestSupport {
+final class ExplicitInitializationCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class ExplicitInitializationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "11:17: " + getCheckMessage(MSG_KEY, "x", 0),
       "12:20: " + getCheckMessage(MSG_KEY, "bar", "null"),
@@ -62,7 +62,7 @@ public class ExplicitInitializationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final ExplicitInitializationCheck check = new ExplicitInitializationCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
@@ -76,7 +76,7 @@ public class ExplicitInitializationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOnlyObjectReferences() throws Exception {
+  void onlyObjectReferences() throws Exception {
     final String[] expected = {
       "12:20: " + getCheckMessage(MSG_KEY, "bar", "null"),
       "21:22: " + getCheckMessage(MSG_KEY, "str1", "null"),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/FallThroughCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/FallThroughCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class FallThroughCheckTest extends AbstractModuleTestSupport {
+final class FallThroughCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class FallThroughCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "22:13: " + getCheckMessage(MSG_FALL_THROUGH),
       "46:13: " + getCheckMessage(MSG_FALL_THROUGH),
@@ -65,13 +65,13 @@ public class FallThroughCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTryWithResources() throws Exception {
+  void tryWithResources() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getNonCompilablePath("InputFallThrough.java"), expected);
   }
 
   @Test
-  public void testTryCatchInSwitch() throws Exception {
+  void tryCatchInSwitch() throws Exception {
     final String[] expected = {
       "37:13: " + getCheckMessage(MSG_FALL_THROUGH),
     };
@@ -79,7 +79,7 @@ public class FallThroughCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStringSwitch() throws Exception {
+  void stringSwitch() throws Exception {
     final String[] expected = {
       "21:9: " + getCheckMessage(MSG_FALL_THROUGH),
     };
@@ -87,7 +87,7 @@ public class FallThroughCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCharacterSwitch() throws Exception {
+  void characterSwitch() throws Exception {
     final String[] expected = {
       "19:13: " + getCheckMessage(MSG_FALL_THROUGH),
       "30:13: " + getCheckMessage(MSG_FALL_THROUGH),
@@ -100,7 +100,7 @@ public class FallThroughCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLastCaseGroup() throws Exception {
+  void lastCaseGroup() throws Exception {
     final String[] expected = {
       "22:13: " + getCheckMessage(MSG_FALL_THROUGH),
       "46:13: " + getCheckMessage(MSG_FALL_THROUGH),
@@ -126,7 +126,7 @@ public class FallThroughCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOwnPattern() throws Exception {
+  void ownPattern() throws Exception {
 
     final String[] expected = {
       "22:13: " + getCheckMessage(MSG_FALL_THROUGH),
@@ -170,7 +170,7 @@ public class FallThroughCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOwnPatternTryWithResources() throws Exception {
+  void ownPatternTryWithResources() throws Exception {
 
     final String[] expected = {
       "54:9: " + getCheckMessage(MSG_FALL_THROUGH),
@@ -183,7 +183,7 @@ public class FallThroughCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithEmoji() throws Exception {
+  void withEmoji() throws Exception {
     final String[] expected = {
       "22:17: " + getCheckMessage(MSG_FALL_THROUGH),
       "25:17: " + getCheckMessage(MSG_FALL_THROUGH),
@@ -194,7 +194,7 @@ public class FallThroughCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final FallThroughCheck check = new FallThroughCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
@@ -208,7 +208,7 @@ public class FallThroughCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFallThroughNoElse() throws Exception {
+  void fallThroughNoElse() throws Exception {
     final String[] expected = {
       "28:13: " + getCheckMessage(MSG_FALL_THROUGH),
       "43:13: " + getCheckMessage(MSG_FALL_THROUGH),
@@ -224,7 +224,7 @@ public class FallThroughCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testYield() throws Exception {
+  void yield() throws Exception {
     final String[] expected = {
       "19:9: " + getCheckMessage(MSG_FALL_THROUGH),
     };
@@ -232,7 +232,7 @@ public class FallThroughCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLastCase() throws Exception {
+  void lastCase() throws Exception {
     final String[] expected = {
       "48:11: " + getCheckMessage(MSG_FALL_THROUGH_LAST),
       "83:11: " + getCheckMessage(MSG_FALL_THROUGH_LAST),
@@ -242,7 +242,7 @@ public class FallThroughCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIfElse() throws Exception {
+  void ifElse() throws Exception {
     final String[] expected = {
       "94:13: " + getCheckMessage(MSG_FALL_THROUGH),
     };
@@ -250,7 +250,7 @@ public class FallThroughCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFallThrough() throws Exception {
+  void fallThrough() throws Exception {
     final String[] expected = {
       "23:13: " + getCheckMessage(MSG_FALL_THROUGH),
       "27:13: " + getCheckMessage(MSG_FALL_THROUGH),
@@ -264,13 +264,13 @@ public class FallThroughCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFallThroughNonCompilable4() throws Exception {
+  void fallThroughNonCompilable4() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getNonCompilablePath("InputFallThrough4.java"), expected);
   }
 
   @Test
-  public void testFallThroughComment() throws Exception {
+  void fallThroughComment() throws Exception {
     final String[] expected = {
       "20:13: " + getCheckMessage(MSG_FALL_THROUGH), "43:13: " + getCheckMessage(MSG_FALL_THROUGH),
     };
@@ -279,14 +279,14 @@ public class FallThroughCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFallThroughComment2() throws Exception {
+  void fallThroughComment2() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputFallThroughFallThroughLotsOfComment2.java"), expected);
   }
 
   @Test
-  public void testFallThrough7() throws Exception {
+  void fallThrough7() throws Exception {
     final String[] expected = {
       "21:13: " + getCheckMessage(MSG_FALL_THROUGH_LAST),
       "36:13: " + getCheckMessage(MSG_FALL_THROUGH_LAST),
@@ -299,7 +299,7 @@ public class FallThroughCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLastLine() throws Exception {
+  void lastLine() throws Exception {
     final String[] expected = {
       "21:13: " + getCheckMessage(MSG_FALL_THROUGH),
       // until https://github.com/checkstyle/checkstyle/issues/13553
@@ -312,7 +312,7 @@ public class FallThroughCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLastLine2() throws Exception {
+  void lastLine2() throws Exception {
     final String[] expected = {
       "19:13: " + getCheckMessage(MSG_FALL_THROUGH_LAST),
       "22:13: " + getCheckMessage(MSG_FALL_THROUGH_LAST),
@@ -321,7 +321,7 @@ public class FallThroughCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testReliefCommentBetweenMultipleComment() throws Exception {
+  void reliefCommentBetweenMultipleComment() throws Exception {
     final String[] expected = {
       // until https://github.com/checkstyle/checkstyle/issues/13553
       "25:17: " + getCheckMessage(MSG_FALL_THROUGH),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/FinalLocalVariableCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/FinalLocalVariableCheckTest.java
@@ -28,7 +28,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
+final class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -36,7 +36,7 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInputFinalLocalVariableOne() throws Exception {
+  void inputFinalLocalVariableOne() throws Exception {
 
     final String[] expected = {
       "17:13: " + getCheckMessage(MSG_KEY, "i"),
@@ -59,7 +59,7 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInputFinalLocalVariableTwo() throws Exception {
+  void inputFinalLocalVariableTwo() throws Exception {
     final String[] expected = {
       "24:17: " + getCheckMessage(MSG_KEY, "weird"),
       "25:17: " + getCheckMessage(MSG_KEY, "j"),
@@ -69,7 +69,7 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInputFinalLocalVariableThree() throws Exception {
+  void inputFinalLocalVariableThree() throws Exception {
     final String[] expected = {
       "14:17: " + getCheckMessage(MSG_KEY, "x"),
       "20:21: " + getCheckMessage(MSG_KEY, "x"),
@@ -86,7 +86,7 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInputFinalLocalVariableFour() throws Exception {
+  void inputFinalLocalVariableFour() throws Exception {
     final String[] expected = {
       "16:17: " + getCheckMessage(MSG_KEY, "shouldBeFinal"),
       "28:17: " + getCheckMessage(MSG_KEY, "shouldBeFinal"),
@@ -98,7 +98,7 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFinalLocalVariableFive() throws Exception {
+  void finalLocalVariableFive() throws Exception {
     final String[] expected = {
       "15:17: " + getCheckMessage(MSG_KEY, "shouldBeFinal"),
       "26:17: " + getCheckMessage(MSG_KEY, "shouldBeFinal"),
@@ -110,7 +110,7 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRecordsInput() throws Exception {
+  void recordsInput() throws Exception {
     final String[] expected = {
       "20:17: " + getCheckMessage(MSG_KEY, "b"),
     };
@@ -119,7 +119,7 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInputFinalLocalVariable2One() throws Exception {
+  void inputFinalLocalVariable2One() throws Exception {
 
     final String[] expected = {
       "52:28: " + getCheckMessage(MSG_KEY, "aArg"),
@@ -128,7 +128,7 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInputFinalLocalVariable2Two() throws Exception {
+  void inputFinalLocalVariable2Two() throws Exception {
 
     final String[] excepted = {
       "78:36: " + getCheckMessage(MSG_KEY, "_o"), "83:37: " + getCheckMessage(MSG_KEY, "_o1"),
@@ -137,7 +137,7 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInputFinalLocalVariable2Three() throws Exception {
+  void inputFinalLocalVariable2Three() throws Exception {
 
     final String[] excepted = {};
 
@@ -145,7 +145,7 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInputFinalLocalVariable2Four() throws Exception {
+  void inputFinalLocalVariable2Four() throws Exception {
 
     final String[] excepted = {};
 
@@ -153,7 +153,7 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInputFinalLocalVariable2Five() throws Exception {
+  void inputFinalLocalVariable2Five() throws Exception {
 
     final String[] excepted = {};
 
@@ -161,21 +161,21 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNativeMethods() throws Exception {
+  void nativeMethods() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputFinalLocalVariableNativeMethods.java"), expected);
   }
 
   @Test
-  public void testFalsePositive() throws Exception {
+  void falsePositive() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputFinalLocalVariableFalsePositive.java"), expected);
   }
 
   @Test
-  public void testEnhancedForLoopVariableTrue() throws Exception {
+  void enhancedForLoopVariableTrue() throws Exception {
     final String[] expected = {
       "16:20: " + getCheckMessage(MSG_KEY, "a"),
       "23:13: " + getCheckMessage(MSG_KEY, "x"),
@@ -190,7 +190,7 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEnhancedForLoopVariableFalse() throws Exception {
+  void enhancedForLoopVariableFalse() throws Exception {
     final String[] expected = {
       "23:13: " + getCheckMessage(MSG_KEY, "x"),
       "29:66: " + getCheckMessage(MSG_KEY, "snippets"),
@@ -202,7 +202,7 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLambda() throws Exception {
+  void lambda() throws Exception {
     final String[] expected = {
       "40:16: " + getCheckMessage(MSG_KEY, "result"),
     };
@@ -210,7 +210,7 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testVariableNameShadowing() throws Exception {
+  void variableNameShadowing() throws Exception {
 
     final String[] expected = {
       "12:28: " + getCheckMessage(MSG_KEY, "text"), "25:13: " + getCheckMessage(MSG_KEY, "x"),
@@ -219,7 +219,7 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testImproperToken() {
+  void improperToken() {
     final FinalLocalVariableCheck check = new FinalLocalVariableCheck();
 
     final DetailAstImpl lambdaAst = new DetailAstImpl();
@@ -234,7 +234,7 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testVariableWhichIsAssignedMultipleTimes() throws Exception {
+  void variableWhichIsAssignedMultipleTimes() throws Exception {
 
     final String[] expected = {
       "57:13: " + getCheckMessage(MSG_KEY, "i"),
@@ -249,7 +249,7 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testVariableIsAssignedInsideAndOutsideSwitchBlock() throws Exception {
+  void variableIsAssignedInsideAndOutsideSwitchBlock() throws Exception {
     final String[] expected = {
       "39:13: " + getCheckMessage(MSG_KEY, "b"),
     };
@@ -258,7 +258,7 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFinalLocalVariableFalsePositives() throws Exception {
+  void finalLocalVariableFalsePositives() throws Exception {
     final String[] expected = {
       "352:16: " + getCheckMessage(MSG_KEY, "c2"), "2195:16: " + getCheckMessage(MSG_KEY, "b"),
     };
@@ -266,27 +266,27 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMultipleAndNestedConditions() throws Exception {
+  void multipleAndNestedConditions() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputFinalLocalVariableMultipleAndNestedConditions.java"), expected);
   }
 
   @Test
-  public void testMultiTypeCatch() throws Exception {
+  void multiTypeCatch() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputFinalLocalVariableMultiCatch.java"), expected);
   }
 
   @Test
-  public void testLeavingSlistToken() throws Exception {
+  void leavingSlistToken() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputFinalLocalVariableLeavingSlistToken.java"), expected);
   }
 
   @Test
-  public void testBreakOrReturn() throws Exception {
+  void breakOrReturn() throws Exception {
     final String[] expected = {
       "15:19: " + getCheckMessage(MSG_KEY, "e"),
     };
@@ -294,7 +294,7 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnonymousClass() throws Exception {
+  void anonymousClass() throws Exception {
     final String[] expected = {
       "13:16: " + getCheckMessage(MSG_KEY, "testSupport"),
     };
@@ -302,14 +302,14 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testReceiverParameter() throws Exception {
+  void receiverParameter() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputFinalLocalVariableReceiverParameter.java"), expected);
   }
 
   @Test
-  public void testFinalLocalVariableSwitchExpressions() throws Exception {
+  void finalLocalVariableSwitchExpressions() throws Exception {
     final String[] expected = {
       "15:19: " + getCheckMessage(MSG_KEY, "e"),
       "53:19: " + getCheckMessage(MSG_KEY, "e"),
@@ -321,7 +321,7 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFinalLocalVariableSwitchAssignment() throws Exception {
+  void finalLocalVariableSwitchAssignment() throws Exception {
     final String[] expected = {
       "21:13: " + getCheckMessage(MSG_KEY, "a"),
       "44:13: " + getCheckMessage(MSG_KEY, "b"),
@@ -334,13 +334,13 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFinalLocalVariableSwitchStatement() throws Exception {
+  void finalLocalVariableSwitchStatement() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputFinalLocalVariableSwitchStatement.java"), expected);
   }
 
   @Test
-  public void testConstructor() throws Exception {
+  void constructor() throws Exception {
     final String[] expected = {
       "14:44: " + getCheckMessage(MSG_KEY, "a"),
       "18:44: " + getCheckMessage(MSG_KEY, "a"),
@@ -352,7 +352,7 @@ public class FinalLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test() throws Exception {
+  void test() throws Exception {
     final String[] expected = {
       "20:17: " + getCheckMessage(MSG_KEY, "start"),
       "22:17: " + getCheckMessage(MSG_KEY, "end"),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/HiddenFieldCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/HiddenFieldCheckTest.java
@@ -34,7 +34,7 @@ import java.util.Optional;
 import java.util.function.Predicate;
 import org.junit.jupiter.api.Test;
 
-public class HiddenFieldCheckTest extends AbstractModuleTestSupport {
+final class HiddenFieldCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -42,7 +42,7 @@ public class HiddenFieldCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticVisibilityFromLambdas() throws Exception {
+  void staticVisibilityFromLambdas() throws Exception {
     final String[] expected = {
       "31:34: " + getCheckMessage(MSG_KEY, "value"),
       "63:31: " + getCheckMessage(MSG_KEY, "languageCode"),
@@ -65,7 +65,7 @@ public class HiddenFieldCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticVisibilityFromAnonymousClasses() throws Exception {
+  void staticVisibilityFromAnonymousClasses() throws Exception {
     final String[] expected = {
       "22:45: " + getCheckMessage(MSG_KEY, "other"),
       "28:42: " + getCheckMessage(MSG_KEY, "other"),
@@ -77,7 +77,7 @@ public class HiddenFieldCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoParameters() throws Exception {
+  void noParameters() throws Exception {
     final String[] expected = {
       "30:13: " + getCheckMessage(MSG_KEY, "hidden"),
       "39:13: " + getCheckMessage(MSG_KEY, "hidden"),
@@ -102,7 +102,7 @@ public class HiddenFieldCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "30:13: " + getCheckMessage(MSG_KEY, "hidden"),
       "33:34: " + getCheckMessage(MSG_KEY, "hidden"),
@@ -145,7 +145,7 @@ public class HiddenFieldCheckTest extends AbstractModuleTestSupport {
 
   /** Tests ignoreFormat property. */
   @Test
-  public void testIgnoreFormat() throws Exception {
+  void ignoreFormat() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(HiddenFieldCheck.class);
     checkConfig.addProperty("ignoreFormat", "^i.*$");
     assertWithMessage("Ignore format should not be null")
@@ -186,7 +186,7 @@ public class HiddenFieldCheckTest extends AbstractModuleTestSupport {
 
   /** Tests ignoreSetter property. */
   @Test
-  public void testIgnoreSetter() throws Exception {
+  void ignoreSetter() throws Exception {
     final String[] expected = {
       "30:13: " + getCheckMessage(MSG_KEY, "hidden"),
       "33:34: " + getCheckMessage(MSG_KEY, "hidden"),
@@ -225,7 +225,7 @@ public class HiddenFieldCheckTest extends AbstractModuleTestSupport {
 
   /** Tests ignoreSetter and setterCanReturnItsClass properties. */
   @Test
-  public void testIgnoreChainSetter() throws Exception {
+  void ignoreChainSetter() throws Exception {
     final String[] expected = {
       "30:13: " + getCheckMessage(MSG_KEY, "hidden"),
       "33:34: " + getCheckMessage(MSG_KEY, "hidden"),
@@ -262,7 +262,7 @@ public class HiddenFieldCheckTest extends AbstractModuleTestSupport {
 
   /** Tests ignoreConstructorParameter property. */
   @Test
-  public void testIgnoreConstructorParameter() throws Exception {
+  void ignoreConstructorParameter() throws Exception {
     final String[] expected = {
       "29:13: " + getCheckMessage(MSG_KEY, "hidden"),
       "38:13: " + getCheckMessage(MSG_KEY, "hidden"),
@@ -302,7 +302,7 @@ public class HiddenFieldCheckTest extends AbstractModuleTestSupport {
 
   /** Test against a class with field declarations in different order. */
   @Test
-  public void testReordered() throws Exception {
+  void reordered() throws Exception {
     final String[] expected = {
       "30:13: " + getCheckMessage(MSG_KEY, "hidden"),
       "33:40: " + getCheckMessage(MSG_KEY, "hidden"),
@@ -329,7 +329,7 @@ public class HiddenFieldCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreAbstractMethods() throws Exception {
+  void ignoreAbstractMethods() throws Exception {
 
     final String[] expected = {
       "30:13: " + getCheckMessage(MSG_KEY, "hidden"),
@@ -371,13 +371,13 @@ public class HiddenFieldCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testReceiverParameter() throws Exception {
+  void receiverParameter() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputHiddenFieldReceiver.java"), expected);
   }
 
   @Test
-  public void testHiddenFieldEnhancedInstanceof() throws Exception {
+  void hiddenFieldEnhancedInstanceof() throws Exception {
 
     final String[] expected = {
       "26:39: " + getCheckMessage(MSG_KEY, "price"),
@@ -388,7 +388,7 @@ public class HiddenFieldCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHiddenFieldSwitchExpression() throws Exception {
+  void hiddenFieldSwitchExpression() throws Exception {
 
     final String[] expected = {
       "28:13: " + getCheckMessage(MSG_KEY, "x"),
@@ -411,7 +411,7 @@ public class HiddenFieldCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHiddenFieldRecords() throws Exception {
+  void hiddenFieldRecords() throws Exception {
 
     final String[] expected = {
       "23:17: " + getCheckMessage(MSG_KEY, "myHiddenInt"),
@@ -428,7 +428,7 @@ public class HiddenFieldCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHiddenFieldLambdasInNestedScope() throws Exception {
+  void hiddenFieldLambdasInNestedScope() throws Exception {
     final String[] expected = {
       "21:34: " + getCheckMessage(MSG_KEY, "value"),
     };
@@ -436,7 +436,7 @@ public class HiddenFieldCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClassNestedInRecord() throws Exception {
+  void classNestedInRecord() throws Exception {
 
     final String[] expected = {
       "23:26: " + getCheckMessage(MSG_KEY, "a"),
@@ -446,7 +446,7 @@ public class HiddenFieldCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHiddenFieldInnerRecordsImplicitlyStatic() throws Exception {
+  void hiddenFieldInnerRecordsImplicitlyStatic() throws Exception {
 
     final String[] expected = {
       "35:30: " + getCheckMessage(MSG_KEY, "pointer"),
@@ -457,7 +457,7 @@ public class HiddenFieldCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHiddenFieldRecordsImplicitlyStaticClassComparison() throws Exception {
+  void hiddenFieldRecordsImplicitlyStaticClassComparison() throws Exception {
 
     final String[] expected = {
       "49:27: " + getCheckMessage(MSG_KEY, "x"),
@@ -475,7 +475,7 @@ public class HiddenFieldCheckTest extends AbstractModuleTestSupport {
    * @throws Exception when code tested throws exception
    */
   @Test
-  public void testClearState() throws Exception {
+  void clearState() throws Exception {
     final HiddenFieldCheck check = new HiddenFieldCheck();
     final DetailAST root =
         JavaParser.parseFile(
@@ -487,7 +487,7 @@ public class HiddenFieldCheckTest extends AbstractModuleTestSupport {
     assertWithMessage("State is not cleared on beginTree")
         .that(
             TestUtil.isStatefulFieldClearedDuringBeginTree(
-                check, classDef.get(), "frame", new CheckIfStatefulFieldCleared()))
+                check, classDef.orElseThrow(), "frame", new CheckIfStatefulFieldCleared()))
         .isTrue();
   }
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalCatchCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalCatchCheckTest.java
@@ -25,7 +25,7 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.IllegalCatchCheck.MS
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class IllegalCatchCheckTest extends AbstractModuleTestSupport {
+final class IllegalCatchCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class IllegalCatchCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
 
     final String[] expected = {
       "14:11: " + getCheckMessage(MSG_KEY, "RuntimeException"),
@@ -48,7 +48,7 @@ public class IllegalCatchCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalClassNames() throws Exception {
+  void illegalClassNames() throws Exception {
     final String[] expected = {
       "14:11: " + getCheckMessage(MSG_KEY, "Exception"),
       "15:11: " + getCheckMessage(MSG_KEY, "Throwable"),
@@ -60,7 +60,7 @@ public class IllegalCatchCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalClassNamesBad() throws Exception {
+  void illegalClassNamesBad() throws Exception {
     // check that incorrect names don't break the Check
     final String[] expected = {
       "15:11: " + getCheckMessage(MSG_KEY, "Exception"),
@@ -71,7 +71,7 @@ public class IllegalCatchCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMultipleTypes() throws Exception {
+  void multipleTypes() throws Exception {
     final String[] expected = {
       "15:11: " + getCheckMessage(MSG_KEY, "RuntimeException"),
       "15:11: " + getCheckMessage(MSG_KEY, "SQLException"),
@@ -90,7 +90,7 @@ public class IllegalCatchCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final IllegalCatchCheck check = new IllegalCatchCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalInstantiationCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalInstantiationCheckTest.java
@@ -37,7 +37,7 @@ import java.util.List;
 import java.util.Optional;
 import org.junit.jupiter.api.Test;
 
-public class IllegalInstantiationCheckTest extends AbstractModuleTestSupport {
+final class IllegalInstantiationCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -45,13 +45,13 @@ public class IllegalInstantiationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputIllegalInstantiationSemantic.java"), expected);
   }
 
   @Test
-  public void testClasses() throws Exception {
+  void classes() throws Exception {
     final String[] expected = {
       "24:21: " + getCheckMessage(MSG_KEY, "java.lang.Boolean"),
       "29:21: " + getCheckMessage(MSG_KEY, "java.lang.Boolean"),
@@ -68,20 +68,20 @@ public class IllegalInstantiationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSameClassNameAsJavaLang() throws Exception {
+  void sameClassNameAsJavaLang() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputIllegalInstantiationSameClassNameJavaLang.java"), expected);
   }
 
   @Test
-  public void testJava8() throws Exception {
+  void java8() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputIllegalInstantiation.java"), expected);
   }
 
   @Test
-  public void testNoPackage() throws Exception {
+  void noPackage() throws Exception {
     final String[] expected = {
       "10:20: " + getCheckMessage(MSG_KEY, "java.lang.Boolean"),
     };
@@ -89,7 +89,7 @@ public class IllegalInstantiationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavaLangPackage() throws Exception {
+  void javaLangPackage() throws Exception {
     final String[] expected = {
       "13:19: " + getCheckMessage(MSG_KEY, "java.lang.Boolean"),
       "21:20: " + getCheckMessage(MSG_KEY, "java.lang.String"),
@@ -99,27 +99,27 @@ public class IllegalInstantiationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWrongPackage() throws Exception {
+  void wrongPackage() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getNonCompilablePath("InputIllegalInstantiationLang2.java"), expected);
   }
 
   @Test
-  public void testJavaLangPackage3() throws Exception {
+  void javaLangPackage3() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputIllegalInstantiationLang3.java"), expected);
   }
 
   @Test
-  public void testNameSimilarToStandardClass() throws Exception {
+  void nameSimilarToStandardClass() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputIllegalInstantiationNameSimilarToStandardClasses.java"), expected);
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final IllegalInstantiationCheck check = new IllegalInstantiationCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
@@ -133,7 +133,7 @@ public class IllegalInstantiationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testImproperToken() {
+  void improperToken() {
     final IllegalInstantiationCheck check = new IllegalInstantiationCheck();
 
     final DetailAstImpl lambdaAst = new DetailAstImpl();
@@ -153,9 +153,9 @@ public class IllegalInstantiationCheckTest extends AbstractModuleTestSupport {
    *
    * @throws Exception when code tested throws exception
    */
-  @Test
   @SuppressWarnings("unchecked")
-  public void testClearStateClassNames() throws Exception {
+  @Test
+  void clearStateClassNames() throws Exception {
     final IllegalInstantiationCheck check = new IllegalInstantiationCheck();
     final DetailAST root =
         JavaParser.parseFile(
@@ -169,7 +169,7 @@ public class IllegalInstantiationCheckTest extends AbstractModuleTestSupport {
         .that(
             TestUtil.isStatefulFieldClearedDuringBeginTree(
                 check,
-                classDef.get(),
+                classDef.orElseThrow(),
                 "classNames",
                 classNames -> ((Collection<String>) classNames).isEmpty()))
         .isTrue();
@@ -182,7 +182,7 @@ public class IllegalInstantiationCheckTest extends AbstractModuleTestSupport {
    * @throws Exception when code tested throws exception
    */
   @Test
-  public void testClearStateImports() throws Exception {
+  void clearStateImports() throws Exception {
     final IllegalInstantiationCheck check = new IllegalInstantiationCheck();
     final DetailAST root =
         JavaParser.parseFile(
@@ -195,7 +195,10 @@ public class IllegalInstantiationCheckTest extends AbstractModuleTestSupport {
     assertWithMessage("State is not cleared on beginTree")
         .that(
             TestUtil.isStatefulFieldClearedDuringBeginTree(
-                check, importDef.get(), "imports", imports -> ((Collection<?>) imports).isEmpty()))
+                check,
+                importDef.orElseThrow(),
+                "imports",
+                imports -> ((Collection<?>) imports).isEmpty()))
         .isTrue();
   }
 
@@ -205,9 +208,9 @@ public class IllegalInstantiationCheckTest extends AbstractModuleTestSupport {
    *
    * @throws Exception when code tested throws exception
    */
-  @Test
   @SuppressWarnings("unchecked")
-  public void testClearStateInstantiations() throws Exception {
+  @Test
+  void clearStateInstantiations() throws Exception {
     final IllegalInstantiationCheck check = new IllegalInstantiationCheck();
     final DetailAST root =
         JavaParser.parseFile(
@@ -221,14 +224,14 @@ public class IllegalInstantiationCheckTest extends AbstractModuleTestSupport {
         .that(
             TestUtil.isStatefulFieldClearedDuringBeginTree(
                 check,
-                literalNew.get(),
+                literalNew.orElseThrow(),
                 "instantiations",
                 instantiations -> ((Collection<DetailAST>) instantiations).isEmpty()))
         .isTrue();
   }
 
   @Test
-  public void testStateIsClearedOnBeginTreePackageName() throws Exception {
+  void stateIsClearedOnBeginTreePackageName() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IllegalInstantiationCheck.class);
     checkConfig.addProperty(
         "classes",
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalThrowsCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalThrowsCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class IllegalThrowsCheckTest extends AbstractModuleTestSupport {
+final class IllegalThrowsCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class IllegalThrowsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
 
     final String[] expected = {
       "19:51: " + getCheckMessage(MSG_KEY, "RuntimeException"),
@@ -46,7 +46,7 @@ public class IllegalThrowsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalClassNames() throws Exception {
+  void illegalClassNames() throws Exception {
     // check that incorrect names don't break the Check
     final String[] expected = {
       "15:33: " + getCheckMessage(MSG_KEY, "NullPointerException"),
@@ -58,7 +58,7 @@ public class IllegalThrowsCheckTest extends AbstractModuleTestSupport {
 
   /** Test to validate the IllegalThrowsCheck with ignoredMethodNames attribute. */
   @Test
-  public void testIgnoreMethodNames() throws Exception {
+  void ignoreMethodNames() throws Exception {
 
     final String[] expected = {
       "19:51: " + getCheckMessage(MSG_KEY, "RuntimeException"),
@@ -70,7 +70,7 @@ public class IllegalThrowsCheckTest extends AbstractModuleTestSupport {
 
   /** Test to validate the IllegalThrowsCheck with both the attributes specified. */
   @Test
-  public void testIllegalClassNamesWithIgnoreMethodNames() throws Exception {
+  void illegalClassNamesWithIgnoreMethodNames() throws Exception {
     final String[] expected = {
       "14:33: " + getCheckMessage(MSG_KEY, "NullPointerException"),
       "27:35: " + getCheckMessage(MSG_KEY, "Throwable"),
@@ -81,7 +81,7 @@ public class IllegalThrowsCheckTest extends AbstractModuleTestSupport {
 
   /** Test to validate the IllegalThrowsCheck with <b>ignoreOverriddenMethods</b> property. */
   @Test
-  public void testIgnoreOverriddenMethods() throws Exception {
+  void ignoreOverriddenMethods() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -91,7 +91,7 @@ public class IllegalThrowsCheckTest extends AbstractModuleTestSupport {
 
   /** Test to validate the IllegalThrowsCheck without <b>ignoreOverriddenMethods</b> property. */
   @Test
-  public void testNotIgnoreOverriddenMethods() throws Exception {
+  void notIgnoreOverriddenMethods() throws Exception {
 
     final String[] expected = {
       "17:36: " + getCheckMessage(MSG_KEY, "RuntimeException"),
@@ -103,7 +103,7 @@ public class IllegalThrowsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final IllegalThrowsCheck check = new IllegalThrowsCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalTokenCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalTokenCheckTest.java
@@ -20,14 +20,14 @@
 package com.puppycrawl.tools.checkstyle.checks.coding;
 
 import static com.puppycrawl.tools.checkstyle.checks.coding.IllegalTokenCheck.MSG_KEY;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.internal.utils.CheckUtil;
 import com.puppycrawl.tools.checkstyle.utils.JavadocUtil;
-import java.nio.charset.StandardCharsets;
 import org.junit.jupiter.api.Test;
 
-public class IllegalTokenCheckTest extends AbstractModuleTestSupport {
+final class IllegalTokenCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class IllegalTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCheckWithDefaultSettings() throws Exception {
+  void checkWithDefaultSettings() throws Exception {
     final String[] expected = {
       "36:14: " + getCheckMessage(MSG_KEY, "label:"),
       "38:25: " + getCheckMessage(MSG_KEY, "anotherLabel:"),
@@ -44,7 +44,7 @@ public class IllegalTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPreviouslyIllegalTokens() throws Exception {
+  void previouslyIllegalTokens() throws Exception {
     final String[] expected = {
       "18:9: " + getCheckMessage(MSG_KEY, "switch"),
       "21:18: " + getCheckMessage(MSG_KEY, "--"),
@@ -54,7 +54,7 @@ public class IllegalTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNative() throws Exception {
+  void testNative() throws Exception {
     final String[] expected = {
       "27:12: " + getCheckMessage(MSG_KEY, "native"),
     };
@@ -62,10 +62,10 @@ public class IllegalTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommentContentToken() throws Exception {
+  void commentContentToken() throws Exception {
 
     final String path = getPath("InputIllegalTokens4.java");
-    final String lineSeparator = CheckUtil.getLineSeparatorForFile(path, StandardCharsets.UTF_8);
+    final String lineSeparator = CheckUtil.getLineSeparatorForFile(path, UTF_8);
     final String[] expected = {
       "1:3: "
           + getCheckMessage(
@@ -99,7 +99,7 @@ public class IllegalTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBlockCommentBeginToken() throws Exception {
+  void blockCommentBeginToken() throws Exception {
 
     final String[] expected = {
       "1:1: " + getCheckMessage(MSG_KEY, "/*"), "10:1: " + getCheckMessage(MSG_KEY, "/*"),
@@ -108,7 +108,7 @@ public class IllegalTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBlockCommentEndToken() throws Exception {
+  void blockCommentEndToken() throws Exception {
 
     final String[] expected = {
       "6:1: " + getCheckMessage(MSG_KEY, "*/"), "12:2: " + getCheckMessage(MSG_KEY, "*/"),
@@ -117,7 +117,7 @@ public class IllegalTokenCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSingleLineCommentToken() throws Exception {
+  void singleLineCommentToken() throws Exception {
 
     final String[] expected = {
       "38:27: " + getCheckMessage(MSG_KEY, "//"), "42:26: " + getCheckMessage(MSG_KEY, "//"),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalTokenTextCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalTokenTextCheckTest.java
@@ -21,6 +21,7 @@ package com.puppycrawl.tools.checkstyle.checks.coding;
 
 import static com.google.common.truth.Truth.assertWithMessage;
 import static com.puppycrawl.tools.checkstyle.checks.coding.IllegalTokenTextCheck.MSG_KEY;
+import static java.util.regex.Pattern.CASE_INSENSITIVE;
 
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
@@ -31,7 +32,7 @@ import java.util.List;
 import java.util.regex.Pattern;
 import org.junit.jupiter.api.Test;
 
-public class IllegalTokenTextCheckTest extends AbstractModuleTestSupport {
+final class IllegalTokenTextCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -39,7 +40,7 @@ public class IllegalTokenTextCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCaseSensitive() throws Exception {
+  void caseSensitive() throws Exception {
     final String[] expected = {
       "34:28: " + getCheckMessage(MSG_KEY, "a href"),
     };
@@ -47,7 +48,7 @@ public class IllegalTokenTextCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCaseInSensitive() throws Exception {
+  void caseInSensitive() throws Exception {
     final String[] expected = {
       "34:28: " + getCheckMessage(MSG_KEY, "a href"),
       "35:32: " + getCheckMessage(MSG_KEY, "a href"),
@@ -56,7 +57,7 @@ public class IllegalTokenTextCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCustomMessage() throws Exception {
+  void customMessage() throws Exception {
 
     final String[] expected = {
       "34:28: " + "My custom message",
@@ -65,7 +66,7 @@ public class IllegalTokenTextCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNullCustomMessage() throws Exception {
+  void nullCustomMessage() throws Exception {
 
     final String[] expected = {
       "34:28: " + getCheckMessage(MSG_KEY, "a href"),
@@ -74,7 +75,7 @@ public class IllegalTokenTextCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalTokenTextTextBlocks() throws Exception {
+  void illegalTokenTextTextBlocks() throws Exception {
 
     final String[] expected = {
       "16:28: " + getCheckMessage(MSG_KEY, "a href"),
@@ -88,7 +89,7 @@ public class IllegalTokenTextCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalTokenTextTextBlocksQuotes() throws Exception {
+  void illegalTokenTextTextBlocksQuotes() throws Exception {
 
     final String[] expected = {
       "16:28: " + getCheckMessage(MSG_KEY, "\""),
@@ -104,7 +105,7 @@ public class IllegalTokenTextCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final IllegalTokenTextCheck check = new IllegalTokenTextCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
@@ -121,7 +122,7 @@ public class IllegalTokenTextCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommentToken() throws Exception {
+  void commentToken() throws Exception {
 
     final String[] expected = {
       "1:3: " + getCheckMessage(MSG_KEY, "a href"), "45:28: " + getCheckMessage(MSG_KEY, "a href"),
@@ -130,7 +131,7 @@ public class IllegalTokenTextCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStringTemplate() throws Exception {
+  void stringTemplate() throws Exception {
 
     final String[] expected = {
       "29:28: " + getCheckMessage(MSG_KEY, "x"),
@@ -146,19 +147,19 @@ public class IllegalTokenTextCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOrderOfProperties() {
+  void orderOfProperties() {
     // pure class must be used as configuration doesn't guarantee order of
     // attributes
     final IllegalTokenTextCheck check = new IllegalTokenTextCheck();
     check.setFormat("test");
     check.setIgnoreCase(true);
     final Pattern actual = TestUtil.getInternalState(check, "format");
-    assertWithMessage("should match").that(actual.flags()).isEqualTo(Pattern.CASE_INSENSITIVE);
+    assertWithMessage("should match").that(actual.flags()).isEqualTo(CASE_INSENSITIVE);
     assertWithMessage("should match").that(actual.pattern()).isEqualTo("test");
   }
 
   @Test
-  public void testAcceptableTokensMakeSense() {
+  void acceptableTokensMakeSense() {
     final int expectedTokenTypesTotalNumber = 194;
     assertWithMessage(
             "Total number of TokenTypes has changed, acceptable tokens in"
@@ -192,7 +193,7 @@ public class IllegalTokenTextCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultFormat() throws Exception {
+  void defaultFormat() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputIllegalTokenTextDefaultFormat.java"), expected);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalTypeCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalTypeCheckTest.java
@@ -31,7 +31,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.io.File;
 import org.junit.jupiter.api.Test;
 
-public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
+final class IllegalTypeCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -39,7 +39,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidateAbstractClassNamesSetToTrue() throws Exception {
+  void validateAbstractClassNamesSetToTrue() throws Exception {
     final String[] expected = {
       "27:38: " + getCheckMessage(MSG_KEY, "AbstractClass"),
       "44:5: " + getCheckMessage(MSG_KEY, "AbstractClass"),
@@ -52,7 +52,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidateAbstractClassNamesSetToFalse() throws Exception {
+  void validateAbstractClassNamesSetToFalse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -60,7 +60,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaults() throws Exception {
+  void defaults() throws Exception {
     final String[] expected = {
       "34:13: " + getCheckMessage(MSG_KEY, "java.util.TreeSet"),
       "35:13: " + getCheckMessage(MSG_KEY, "TreeSet"),
@@ -72,7 +72,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultsEmptyStringMemberModifiers() throws Exception {
+  void defaultsEmptyStringMemberModifiers() throws Exception {
 
     final String[] expected = {
       "34:13: " + getCheckMessage(MSG_KEY, "java.util.TreeSet"),
@@ -86,7 +86,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreMethodNames() throws Exception {
+  void ignoreMethodNames() throws Exception {
     final String[] expected = {
       "23:13: " + getCheckMessage(MSG_KEY, "AbstractClass"),
       "26:13: "
@@ -104,7 +104,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFormat() throws Exception {
+  void format() throws Exception {
 
     final String[] expected = {
       "34:13: " + getCheckMessage(MSG_KEY, "java.util.TreeSet"),
@@ -117,7 +117,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLegalAbstractClassNames() throws Exception {
+  void legalAbstractClassNames() throws Exception {
 
     final String[] expected = {
       "26:13: "
@@ -136,7 +136,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSameFileNameFalsePositive() throws Exception {
+  void sameFileNameFalsePositive() throws Exception {
     final String[] expected = {
       "28:5: " + getCheckMessage(MSG_KEY, "SubCal"),
       "43:5: " + getCheckMessage(MSG_KEY, "java.util.List"),
@@ -147,7 +147,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSameFileNameGeneral() throws Exception {
+  void sameFileNameGeneral() throws Exception {
     final String[] expected = {
       "25:5: " + getCheckMessage(MSG_KEY, "InputIllegalTypeGregCal"),
       "29:43: " + getCheckMessage(MSG_KEY, "InputIllegalTypeGregCal"),
@@ -162,7 +162,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testArrayTypes() throws Exception {
+  void arrayTypes() throws Exception {
     final String[] expected = {
       "20:12: " + getCheckMessage(MSG_KEY, "Boolean[]"),
       "22:12: " + getCheckMessage(MSG_KEY, "Boolean[][]"),
@@ -175,7 +175,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPlainAndArrayTypes() throws Exception {
+  void plainAndArrayTypes() throws Exception {
     final String[] expected = {
       "20:12: " + getCheckMessage(MSG_KEY, "Boolean"),
       "24:12: " + getCheckMessage(MSG_KEY, "Boolean[][]"),
@@ -187,7 +187,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGenerics() throws Exception {
+  void generics() throws Exception {
     final String[] expected = {
       "28:16: " + getCheckMessage(MSG_KEY, "Boolean"),
       "29:31: " + getCheckMessage(MSG_KEY, "Boolean"),
@@ -211,7 +211,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExtendsImplements() throws Exception {
+  void extendsImplements() throws Exception {
     final String[] expected = {
       "24:17: " + getCheckMessage(MSG_KEY, "Hashtable"),
       "25:14: " + getCheckMessage(MSG_KEY, "Boolean"),
@@ -227,7 +227,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStarImports() throws Exception {
+  void starImports() throws Exception {
 
     final String[] expected = {
       "24:5: " + getCheckMessage(MSG_KEY, "List"),
@@ -237,7 +237,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticImports() throws Exception {
+  void staticImports() throws Exception {
 
     final String[] expected = {
       "26:6: " + getCheckMessage(MSG_KEY, "SomeStaticClass"),
@@ -248,7 +248,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMemberModifiers() throws Exception {
+  void memberModifiers() throws Exception {
     final String[] expected = {
       "22:13: " + getCheckMessage(MSG_KEY, "AbstractClass"),
       "25:13: " + getCheckMessage(MSG_KEY, "java.util.AbstractList"),
@@ -263,7 +263,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackageClassName() throws Exception {
+  void packageClassName() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -271,7 +271,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClearDataBetweenFiles() throws Exception {
+  void clearDataBetweenFiles() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IllegalTypeCheck.class);
     final String violationFile = getPath("InputIllegalTypeTestClearDataBetweenFiles.java");
     checkConfig.addProperty("illegalClassNames", "java.util.TreeSet");
@@ -290,7 +290,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalTypeEnhancedInstanceof() throws Exception {
+  void illegalTypeEnhancedInstanceof() throws Exception {
     final String[] expected = {
       "28:9: " + getCheckMessage(MSG_KEY, "LinkedHashMap"),
       "31:28: " + getCheckMessage(MSG_KEY, "LinkedHashMap"),
@@ -304,7 +304,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalTypeRecordsAndCompactCtors() throws Exception {
+  void illegalTypeRecordsAndCompactCtors() throws Exception {
     final String[] expected = {
       "27:14: " + getCheckMessage(MSG_KEY, "LinkedHashMap"),
       "31:52: " + getCheckMessage(MSG_KEY, "Cloneable"),
@@ -320,7 +320,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalTypeNewArrayStructure() throws Exception {
+  void illegalTypeNewArrayStructure() throws Exception {
 
     final String[] expected = {
       "26:13: " + getCheckMessage(MSG_KEY, "HashMap"),
@@ -330,7 +330,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRecordComponentsDefault() throws Exception {
+  void recordComponentsDefault() throws Exception {
     final String[] expected = {
       "45:9: " + getCheckMessage(MSG_KEY, "HashSet"),
       "53:23: " + getCheckMessage(MSG_KEY, "HashSet"),
@@ -341,7 +341,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRecordComponentsFinal() throws Exception {
+  void recordComponentsFinal() throws Exception {
     final String[] expected = {
       "45:9: " + getCheckMessage(MSG_KEY, "HashSet"),
       "53:23: " + getCheckMessage(MSG_KEY, "HashSet"),
@@ -352,7 +352,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRecordComponentsPrivateFinal() throws Exception {
+  void recordComponentsPrivateFinal() throws Exception {
     final String[] expected = {
       "45:9: " + getCheckMessage(MSG_KEY, "HashSet"),
       "53:23: " + getCheckMessage(MSG_KEY, "HashSet"),
@@ -364,7 +364,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRecordComponentsPublicProtectedStatic() throws Exception {
+  void recordComponentsPublicProtectedStatic() throws Exception {
     final String[] expected = {"45:9: " + getCheckMessage(MSG_KEY, "HashSet")};
 
     verifyWithInlineConfigParser(
@@ -374,13 +374,13 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTrailingWhitespaceInConfig() throws Exception {
+  void trailingWhitespaceInConfig() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputIllegalTypeWhitespaceInConfig.java"), expected);
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final IllegalTypeCheck check = new IllegalTypeCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
@@ -394,7 +394,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testImproperToken() {
+  void improperToken() {
     final IllegalTypeCheck check = new IllegalTypeCheck();
 
     final DetailAstImpl classDefAst = new DetailAstImpl();
@@ -414,7 +414,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
    * beneficial.
    */
   @Test
-  public void testImproperLeaveToken() {
+  void improperLeaveToken() {
     final IllegalTypeCheck check = new IllegalTypeCheck();
     final DetailAstImpl enumAst = new DetailAstImpl();
     enumAst.setType(TokenTypes.ENUM_DEF);
@@ -430,7 +430,7 @@ public class IllegalTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalTypeAbstractClassNameFormat() throws Exception {
+  void illegalTypeAbstractClassNameFormat() throws Exception {
     final String[] expected = {
       "15:20: " + getCheckMessage(MSG_KEY, "Gitter"),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/InnerAssignmentCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/InnerAssignmentCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class InnerAssignmentCheckTest extends AbstractModuleTestSupport {
+final class InnerAssignmentCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class InnerAssignmentCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIt() throws Exception {
+  void it() throws Exception {
     final String[] expected = {
       "22:15: " + getCheckMessage(MSG_KEY),
       "22:19: " + getCheckMessage(MSG_KEY),
@@ -46,7 +46,7 @@ public class InnerAssignmentCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMethod() throws Exception {
+  void method() throws Exception {
     final String[] expected = {
       "73:22: " + getCheckMessage(MSG_KEY),
     };
@@ -54,7 +54,7 @@ public class InnerAssignmentCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDemoBug1195047Comment3() throws Exception {
+  void demoBug1195047Comment3() throws Exception {
     final String[] expected = {
       "18:16: " + getCheckMessage(MSG_KEY),
       "19:24: " + getCheckMessage(MSG_KEY),
@@ -74,13 +74,13 @@ public class InnerAssignmentCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLambdaExpression() throws Exception {
+  void lambdaExpression() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputInnerAssignmentLambdaExpressions.java"), expected);
   }
 
   @Test
-  public void testInnerAssignmentNotInLoopContext() throws Exception {
+  void innerAssignmentNotInLoopContext() throws Exception {
     final String[] expected = {
       "12:28: " + getCheckMessage(MSG_KEY),
     };
@@ -88,7 +88,7 @@ public class InnerAssignmentCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final InnerAssignmentCheck check = new InnerAssignmentCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/MagicNumberCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/MagicNumberCheckTest.java
@@ -25,7 +25,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class MagicNumberCheckTest extends AbstractModuleTestSupport {
+final class MagicNumberCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,13 +33,13 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLocalVariables() throws Exception {
+  void localVariables() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMagicNumberLocalVariables.java"), expected);
   }
 
   @Test
-  public void testLocalVariables2() throws Exception {
+  void localVariables2() throws Exception {
     final String[] expected = {
       "25:17: " + getCheckMessage(MSG_KEY, "8"),
     };
@@ -47,7 +47,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault1() throws Exception {
+  void default1() throws Exception {
     final String[] expected = {
       "54:26: " + getCheckMessage(MSG_KEY, "3_000"),
       "55:32: " + getCheckMessage(MSG_KEY, "1.5_0"),
@@ -75,7 +75,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault2() throws Exception {
+  void default2() throws Exception {
     final String[] expected = {
       "21:14: " + getCheckMessage(MSG_KEY, "0xffffffffL"),
       "28:30: " + getCheckMessage(MSG_KEY, "+3"),
@@ -92,7 +92,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault3() throws Exception {
+  void default3() throws Exception {
     final String[] expected = {
       "20:16: " + getCheckMessage(MSG_KEY, "31"),
       "25:16: " + getCheckMessage(MSG_KEY, "42"),
@@ -114,7 +114,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreSome1() throws Exception {
+  void ignoreSome1() throws Exception {
     final String[] expected = {
       "36:25: " + getCheckMessage(MSG_KEY, "2"),
       "42:35: " + getCheckMessage(MSG_KEY, "2"),
@@ -136,7 +136,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreSome2() throws Exception {
+  void ignoreSome2() throws Exception {
     final String[] expected = {
       "21:14: " + getCheckMessage(MSG_KEY, "0xffffffffL"),
       "30:29: " + getCheckMessage(MSG_KEY, "-2"),
@@ -156,7 +156,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreSome3() throws Exception {
+  void ignoreSome3() throws Exception {
     final String[] expected = {
       "21:16: " + getCheckMessage(MSG_KEY, "31"),
       "26:16: " + getCheckMessage(MSG_KEY, "42"),
@@ -174,7 +174,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreNone1() throws Exception {
+  void ignoreNone1() throws Exception {
     final String[] expected = {
       "41:24: " + getCheckMessage(MSG_KEY, "1"),
       "42:25: " + getCheckMessage(MSG_KEY, "2"),
@@ -223,7 +223,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreNone2() throws Exception {
+  void ignoreNone2() throws Exception {
     final String[] expected = {
       "19:14: " + getCheckMessage(MSG_KEY, "0xffffffffL"),
       "26:30: " + getCheckMessage(MSG_KEY, "+3"),
@@ -244,7 +244,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreNone3() throws Exception {
+  void ignoreNone3() throws Exception {
     final String[] expected = {
       "20:16: " + getCheckMessage(MSG_KEY, "31"),
       "25:16: " + getCheckMessage(MSG_KEY, "42"),
@@ -262,7 +262,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIntegersOnly1() throws Exception {
+  void integersOnly1() throws Exception {
     final String[] expected = {
       "55:26: " + getCheckMessage(MSG_KEY, "3_000"),
       "57:27: " + getCheckMessage(MSG_KEY, "3"),
@@ -288,7 +288,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIntegersOnly2() throws Exception {
+  void integersOnly2() throws Exception {
     final String[] expected = {
       "20:14: " + getCheckMessage(MSG_KEY, "0xffffffffL"),
       "28:30: " + getCheckMessage(MSG_KEY, "+3"),
@@ -303,7 +303,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIntegersOnly3() throws Exception {
+  void integersOnly3() throws Exception {
     final String[] expected = {
       "20:16: " + getCheckMessage(MSG_KEY, "31"),
       "25:16: " + getCheckMessage(MSG_KEY, "42"),
@@ -321,7 +321,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreNegativeOctalHex1() throws Exception {
+  void ignoreNegativeOctalHex1() throws Exception {
     final String[] expected = {
       "55:26: " + getCheckMessage(MSG_KEY, "3_000"),
       "57:27: " + getCheckMessage(MSG_KEY, "3"),
@@ -347,7 +347,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreNegativeOctalHex2() throws Exception {
+  void ignoreNegativeOctalHex2() throws Exception {
     final String[] expected = {
       "20:14: " + getCheckMessage(MSG_KEY, "0xffffffffL"),
       "28:30: " + getCheckMessage(MSG_KEY, "+3"),
@@ -357,7 +357,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreNegativeOctalHex3() throws Exception {
+  void ignoreNegativeOctalHex3() throws Exception {
     final String[] expected = {
       "20:16: " + getCheckMessage(MSG_KEY, "31"),
       "25:16: " + getCheckMessage(MSG_KEY, "42"),
@@ -375,7 +375,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreHashCodeMethod() throws Exception {
+  void ignoreHashCodeMethod() throws Exception {
     final String[] expected = {
       "55:26: " + getCheckMessage(MSG_KEY, "3_000"),
       "56:32: " + getCheckMessage(MSG_KEY, "1.5_0"),
@@ -403,7 +403,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreHashCodeMethod2() throws Exception {
+  void ignoreHashCodeMethod2() throws Exception {
     final String[] expected = {
       "20:14: " + getCheckMessage(MSG_KEY, "0xffffffffL"),
       "27:30: " + getCheckMessage(MSG_KEY, "+3"),
@@ -420,7 +420,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreHashCodeMethod3() throws Exception {
+  void ignoreHashCodeMethod3() throws Exception {
     final String[] expected = {
       "25:16: " + getCheckMessage(MSG_KEY, "42"),
       "30:16: " + getCheckMessage(MSG_KEY, "13"),
@@ -437,7 +437,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreFieldDeclaration1() throws Exception {
+  void ignoreFieldDeclaration1() throws Exception {
     final String[] expected = {
       "55:26: " + getCheckMessage(MSG_KEY, "3_000"),
       "56:32: " + getCheckMessage(MSG_KEY, "1.5_0"),
@@ -464,7 +464,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreFieldDeclaration2() throws Exception {
+  void ignoreFieldDeclaration2() throws Exception {
     final String[] expected = {
       "49:20: " + getCheckMessage(MSG_KEY, "378"),
     };
@@ -472,7 +472,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreFieldDeclaration3() throws Exception {
+  void ignoreFieldDeclaration3() throws Exception {
     final String[] expected = {
       "20:16: " + getCheckMessage(MSG_KEY, "31"),
       "25:16: " + getCheckMessage(MSG_KEY, "42"),
@@ -490,7 +490,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWaiverParentToken() throws Exception {
+  void waiverParentToken() throws Exception {
     final String[] expected = {
       "55:26: " + getCheckMessage(MSG_KEY, "3_000"),
       "56:32: " + getCheckMessage(MSG_KEY, "1.5_0"),
@@ -518,7 +518,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWaiverParentToken2() throws Exception {
+  void waiverParentToken2() throws Exception {
     final String[] expected = {
       "20:14: " + getCheckMessage(MSG_KEY, "0xffffffffL"),
       "28:30: " + getCheckMessage(MSG_KEY, "+3"),
@@ -540,7 +540,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWaiverParentToken3() throws Exception {
+  void waiverParentToken3() throws Exception {
     final String[] expected = {
       "20:16: " + getCheckMessage(MSG_KEY, "31"),
       "25:16: " + getCheckMessage(MSG_KEY, "42"),
@@ -563,7 +563,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMagicNumberRecordsDefault() throws Exception {
+  void magicNumberRecordsDefault() throws Exception {
     final String[] expected = {
       "19:11: " + getCheckMessage(MSG_KEY, "6"),
       "21:36: " + getCheckMessage(MSG_KEY, "7"),
@@ -576,7 +576,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMagicNumberIgnoreFieldDeclarationRecords() throws Exception {
+  void magicNumberIgnoreFieldDeclarationRecords() throws Exception {
     final String[] expected = {
       "19:11: " + getCheckMessage(MSG_KEY, "6"),
       "25:29: " + getCheckMessage(MSG_KEY, "8"),
@@ -588,7 +588,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreInAnnotationElementDefault() throws Exception {
+  void ignoreInAnnotationElementDefault() throws Exception {
     final String[] expected = {
       "18:29: " + getCheckMessage(MSG_KEY, "10"), "19:33: " + getCheckMessage(MSG_KEY, "11"),
     };
@@ -596,7 +596,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMagicNumber() throws Exception {
+  void magicNumber() throws Exception {
     final String[] expected = {
       "38:29: " + getCheckMessage(MSG_KEY, "3.0"),
       "39:32: " + getCheckMessage(MSG_KEY, "1.5_0"),
@@ -635,7 +635,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMagicNumber2() throws Exception {
+  void magicNumber2() throws Exception {
     final String[] expected = {
       "25:17: " + getCheckMessage(MSG_KEY, "9"),
       "27:20: " + getCheckMessage(MSG_KEY, "5.5"),
@@ -659,7 +659,7 @@ public class MagicNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMagicNumber3() throws Exception {
+  void magicNumber3() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMagicNumberMagicNumber3.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/MatchXpathCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/MatchXpathCheckTest.java
@@ -30,7 +30,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class MatchXpathCheckTest extends AbstractModuleTestSupport {
+final class MatchXpathCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -38,25 +38,25 @@ public class MatchXpathCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCheckWithEmptyQuery() throws Exception {
+  void checkWithEmptyQuery() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMatchXpath.java"), expected);
   }
 
   @Test
-  public void testNoStackoverflowError() throws Exception {
+  void noStackoverflowError() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMatchXpathNoStackoverflowError.java"), expected);
   }
 
   @Test
-  public void testCheckWithImplicitEmptyQuery() throws Exception {
+  void checkWithImplicitEmptyQuery() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMatchXpath2.java"), expected);
   }
 
   @Test
-  public void testCheckWithMatchingMethodNames() throws Exception {
+  void checkWithMatchingMethodNames() throws Exception {
     final String[] expected = {
       "11:5: " + getCheckMessage(MatchXpathCheck.MSG_KEY),
       "13:5: " + getCheckMessage(MatchXpathCheck.MSG_KEY),
@@ -65,13 +65,13 @@ public class MatchXpathCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCheckWithNoMatchingMethodName() throws Exception {
+  void checkWithNoMatchingMethodName() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMatchXpath4.java"), expected);
   }
 
   @Test
-  public void testCheckWithSingleLineCommentsStartsWithSpace() throws Exception {
+  void checkWithSingleLineCommentsStartsWithSpace() throws Exception {
     final String[] expected = {
       "13:25: " + getCheckMessage(MatchXpathCheck.MSG_KEY),
       "14:27: " + getCheckMessage(MatchXpathCheck.MSG_KEY),
@@ -80,7 +80,7 @@ public class MatchXpathCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCheckWithBlockComments() throws Exception {
+  void checkWithBlockComments() throws Exception {
     final String[] expected = {
       "12:5: " + getCheckMessage(MatchXpathCheck.MSG_KEY),
       "14:5: " + getCheckMessage(MatchXpathCheck.MSG_KEY),
@@ -89,7 +89,7 @@ public class MatchXpathCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCheckWithMultilineComments() throws Exception {
+  void checkWithMultilineComments() throws Exception {
     final String[] expected = {
       "14:5: " + getCheckMessage(MatchXpathCheck.MSG_KEY),
       "20:5: " + getCheckMessage(MatchXpathCheck.MSG_KEY),
@@ -98,7 +98,7 @@ public class MatchXpathCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCheckWithDoubleBraceInitialization() throws Exception {
+  void checkWithDoubleBraceInitialization() throws Exception {
     final String[] expected = {
       "18:35: Do not use double-brace initialization",
     };
@@ -106,7 +106,7 @@ public class MatchXpathCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testImitateIllegalThrowsCheck() throws Exception {
+  void imitateIllegalThrowsCheck() throws Exception {
     final String[] expected = {
       "13:25: Illegal throws statement",
       "15:25: Illegal throws statement",
@@ -116,7 +116,7 @@ public class MatchXpathCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testImitateExecutableStatementCountCheck() throws Exception {
+  void imitateExecutableStatementCountCheck() throws Exception {
     final String[] expected = {
       "25:5: Executable number of statements exceed threshold",
     };
@@ -124,7 +124,7 @@ public class MatchXpathCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testForbidPrintStackTrace() throws Exception {
+  void forbidPrintStackTrace() throws Exception {
     final String[] expected = {
       "18:27: printStackTrace() method calls are forbidden",
     };
@@ -132,7 +132,7 @@ public class MatchXpathCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testForbidParameterizedConstructor() throws Exception {
+  void forbidParameterizedConstructor() throws Exception {
     final String[] expected = {
       "13:5: Parameterized constructors are not allowed",
       "15:5: Parameterized constructors are not allowed",
@@ -142,7 +142,7 @@ public class MatchXpathCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAvoidInstanceCreationWithoutVar() throws Exception {
+  void avoidInstanceCreationWithoutVar() throws Exception {
     final String[] expected = {
       "13:9: " + getCheckMessage(MatchXpathCheck.MSG_KEY),
     };
@@ -151,7 +151,7 @@ public class MatchXpathCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidQuery() {
+  void invalidQuery() {
     final MatchXpathCheck matchXpathCheck = new MatchXpathCheck();
 
     try {
@@ -163,7 +163,7 @@ public class MatchXpathCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEvaluationException() {
+  void evaluationException() {
     final MatchXpathCheck matchXpathCheck = new MatchXpathCheck();
     matchXpathCheck.setQuery("count(*) div 0");
 
@@ -182,25 +182,25 @@ public class MatchXpathCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetDefaultTokens() {
+  void getDefaultTokens() {
     final MatchXpathCheck matchXpathCheck = new MatchXpathCheck();
     assertWithMessage("Expected empty array").that(matchXpathCheck.getDefaultTokens()).isEmpty();
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final MatchXpathCheck matchXpathCheck = new MatchXpathCheck();
     assertWithMessage("Expected empty array").that(matchXpathCheck.getAcceptableTokens()).isEmpty();
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final MatchXpathCheck matchXpathCheck = new MatchXpathCheck();
     assertWithMessage("Expected empty array").that(matchXpathCheck.getRequiredTokens()).isEmpty();
   }
 
   @Test
-  public void testMatchXpathWithFailedEvaluation() {
+  void matchXpathWithFailedEvaluation() {
     final CheckstyleException ex =
         assertThrows(
             CheckstyleException.class,
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/MissingCtorCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/MissingCtorCheckTest.java
@@ -25,7 +25,7 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.MissingCtorCheck.MSG
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class MissingCtorCheckTest extends AbstractModuleTestSupport {
+final class MissingCtorCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class MissingCtorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMissingSwitchDefault() throws Exception {
+  void missingSwitchDefault() throws Exception {
 
     final String[] expected = {
       "9:1: " + getCheckMessage(MSG_KEY),
@@ -43,7 +43,7 @@ public class MissingCtorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final MissingCtorCheck check = new MissingCtorCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
@@ -57,7 +57,7 @@ public class MissingCtorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMissingCtorClassOnOneLine() throws Exception {
+  void missingCtorClassOnOneLine() throws Exception {
 
     final String[] expected = {
       "9:1: " + getCheckMessage(MSG_KEY),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/MissingSwitchDefaultCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/MissingSwitchDefaultCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class MissingSwitchDefaultCheckTest extends AbstractModuleTestSupport {
+final class MissingSwitchDefaultCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class MissingSwitchDefaultCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMissingSwitchDefault() throws Exception {
+  void missingSwitchDefault() throws Exception {
     final String[] expected = {
       "23:9: " + getCheckMessage(MSG_KEY, "default"),
       "35:17: " + getCheckMessage(MSG_KEY, "default"),
@@ -45,7 +45,7 @@ public class MissingSwitchDefaultCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final MissingSwitchDefaultCheck check = new MissingSwitchDefaultCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
@@ -59,7 +59,7 @@ public class MissingSwitchDefaultCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMissingSwitchDefaultSwitchExpressions() throws Exception {
+  void missingSwitchDefaultSwitchExpressions() throws Exception {
     final String[] expected = {
       "14:9: " + getCheckMessage(MSG_KEY, "default"),
     };
@@ -68,14 +68,14 @@ public class MissingSwitchDefaultCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNullCaseLabel() throws Exception {
+  void nullCaseLabel() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getNonCompilablePath("InputMissingSwitchDefaultCheckNullCaseLabel.java"), expected);
   }
 
   @Test
-  public void testMissingSwitchDefaultSwitchExpressionsTwo() throws Exception {
+  void missingSwitchDefaultSwitchExpressionsTwo() throws Exception {
     final String[] expected = {
       "14:9: " + getCheckMessage(MSG_KEY, "default"),
       "26:9: " + getCheckMessage(MSG_KEY, "default"),
@@ -85,7 +85,7 @@ public class MissingSwitchDefaultCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMissingSwitchDefaultSwitchExpressionsThree() throws Exception {
+  void missingSwitchDefaultSwitchExpressionsThree() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getNonCompilablePath("InputMissingSwitchDefaultCheckSwitchExpressionsThree.java"),
@@ -93,7 +93,7 @@ public class MissingSwitchDefaultCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMissingSwitchDefaultCaseLabelElements() throws Exception {
+  void missingSwitchDefaultCaseLabelElements() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getNonCompilablePath("InputMissingSwitchDefaultCaseLabelElements.java"), expected);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/ModifiedControlVariableCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/ModifiedControlVariableCheckTest.java
@@ -35,7 +35,7 @@ import java.util.Optional;
 import java.util.Set;
 import org.junit.jupiter.api.Test;
 
-public class ModifiedControlVariableCheckTest extends AbstractModuleTestSupport {
+final class ModifiedControlVariableCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -43,7 +43,7 @@ public class ModifiedControlVariableCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testModifiedControlVariable() throws Exception {
+  void modifiedControlVariable() throws Exception {
     final String[] expected = {
       "17:14: " + getCheckMessage(MSG_KEY, "i"),
       "20:15: " + getCheckMessage(MSG_KEY, "i"),
@@ -60,7 +60,7 @@ public class ModifiedControlVariableCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testEnhancedForLoopVariableTrue() throws Exception {
+  void enhancedForLoopVariableTrue() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
@@ -68,7 +68,7 @@ public class ModifiedControlVariableCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testEnhancedForLoopVariableFalse() throws Exception {
+  void enhancedForLoopVariableFalse() throws Exception {
 
     final String[] expected = {
       "16:18: " + getCheckMessage(MSG_KEY, "line"),
@@ -78,7 +78,7 @@ public class ModifiedControlVariableCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testEnhancedForLoopVariable2() throws Exception {
+  void enhancedForLoopVariable2() throws Exception {
 
     final String[] expected = {
       "21:18: " + getCheckMessage(MSG_KEY, "i"),
@@ -88,7 +88,7 @@ public class ModifiedControlVariableCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final ModifiedControlVariableCheck check = new ModifiedControlVariableCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
@@ -102,7 +102,7 @@ public class ModifiedControlVariableCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testImproperToken() {
+  void improperToken() {
     final ModifiedControlVariableCheck check = new ModifiedControlVariableCheck();
 
     final DetailAstImpl classDefAst = new DetailAstImpl();
@@ -124,7 +124,7 @@ public class ModifiedControlVariableCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testVariousAssignments() throws Exception {
+  void variousAssignments() throws Exception {
     final String[] expected = {
       "14:15: " + getCheckMessage(MSG_KEY, "i"),
       "15:15: " + getCheckMessage(MSG_KEY, "k"),
@@ -154,7 +154,7 @@ public class ModifiedControlVariableCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testRecordDecompositionInEnhancedForLoop() throws Exception {
+  void recordDecompositionInEnhancedForLoop() throws Exception {
     final String[] expected = {
       "32:15: " + getCheckMessage(MSG_KEY, "p"),
     };
@@ -168,9 +168,9 @@ public class ModifiedControlVariableCheckTest extends AbstractModuleTestSupport
    *
    * @throws Exception when code tested throws exception
    */
-  @Test
   @SuppressWarnings("unchecked")
-  public void testClearState() throws Exception {
+  @Test
+  void clearState() throws Exception {
     final ModifiedControlVariableCheck check = new ModifiedControlVariableCheck();
     final Optional<DetailAST> methodDef =
         TestUtil.findTokenInAstByPredicate(
@@ -184,7 +184,7 @@ public class ModifiedControlVariableCheckTest extends AbstractModuleTestSupport
         .that(
             TestUtil.isStatefulFieldClearedDuringBeginTree(
                 check,
-                methodDef.get(),
+                methodDef.orElseThrow(),
                 "variableStack",
                 variableStack -> ((Collection<Set<String>>) variableStack).isEmpty()))
         .isTrue();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/MultipleStringLiteralsCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/MultipleStringLiteralsCheckTest.java
@@ -31,7 +31,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class MultipleStringLiteralsCheckTest extends AbstractModuleTestSupport {
+final class MultipleStringLiteralsCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -39,7 +39,7 @@ public class MultipleStringLiteralsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIt() throws Exception {
+  void it() throws Exception {
 
     final String[] expected = {
       "14:16: " + getCheckMessage(MSG_KEY, "\"StringContents\"", 3),
@@ -51,7 +51,7 @@ public class MultipleStringLiteralsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testItIgnoreEmpty() throws Exception {
+  void itIgnoreEmpty() throws Exception {
 
     final String[] expected = {
       "14:16: " + getCheckMessage(MSG_KEY, "\"StringContents\"", 3),
@@ -62,7 +62,7 @@ public class MultipleStringLiteralsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMultipleInputs() throws Exception {
+  void multipleInputs() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(MultipleStringLiteralsCheck.class);
     checkConfig.addProperty("allowedDuplicates", "2");
 
@@ -84,7 +84,7 @@ public class MultipleStringLiteralsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testItIgnoreEmptyAndComspace() throws Exception {
+  void itIgnoreEmptyAndComspace() throws Exception {
 
     final String[] expected = {
       "14:16: " + getCheckMessage(MSG_KEY, "\"StringContents\"", 3),
@@ -94,7 +94,7 @@ public class MultipleStringLiteralsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testItWithoutIgnoringAnnotations() throws Exception {
+  void itWithoutIgnoringAnnotations() throws Exception {
 
     final String[] expected = {
       "28:23: " + getCheckMessage(MSG_KEY, "\"unchecked\"", 4),
@@ -104,7 +104,7 @@ public class MultipleStringLiteralsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final MultipleStringLiteralsCheck check = new MultipleStringLiteralsCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
@@ -118,7 +118,7 @@ public class MultipleStringLiteralsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultConfiguration() throws Exception {
+  void defaultConfiguration() throws Exception {
     final String[] expected = {
       "14:16: " + getCheckMessage(MSG_KEY, "\"StringContents\"", 3),
       "16:17: " + getCheckMessage(MSG_KEY, "\"DoubleString\"", 2),
@@ -129,7 +129,7 @@ public class MultipleStringLiteralsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnores() throws Exception {
+  void ignores() throws Exception {
     final String[] expected = {
       "28:23: " + getCheckMessage(MSG_KEY, "\"unchecked\"", 4),
     };
@@ -138,7 +138,7 @@ public class MultipleStringLiteralsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMultipleStringLiteralsTextBlocks() throws Exception {
+  void multipleStringLiteralsTextBlocks() throws Exception {
 
     final String[] expected = {
       "14:22: " + getCheckMessage(MSG_KEY, "\"string\"", 3),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/MultipleVariableDeclarationsCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/MultipleVariableDeclarationsCheckTest.java
@@ -26,7 +26,7 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.MultipleVariableDecl
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class MultipleVariableDeclarationsCheckTest extends AbstractModuleTestSupport {
+final class MultipleVariableDeclarationsCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class MultipleVariableDeclarationsCheckTest extends AbstractModuleTestSup
   }
 
   @Test
-  public void testIt() throws Exception {
+  void it() throws Exception {
 
     final String[] expected = {
       "11:5: " + getCheckMessage(MSG_MULTIPLE_COMMA),
@@ -52,7 +52,7 @@ public class MultipleVariableDeclarationsCheckTest extends AbstractModuleTestSup
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final MultipleVariableDeclarationsCheck check = new MultipleVariableDeclarationsCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
@@ -66,7 +66,7 @@ public class MultipleVariableDeclarationsCheckTest extends AbstractModuleTestSup
   }
 
   @Test
-  public void test() throws Exception {
+  void test() throws Exception {
 
     final String[] expected = {
       "11:5: " + getCheckMessage(MSG_MULTIPLE), "14:5: " + getCheckMessage(MSG_MULTIPLE),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/NestedForDepthCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/NestedForDepthCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class NestedForDepthCheckTest extends AbstractModuleTestSupport {
+final class NestedForDepthCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -41,7 +41,7 @@ public class NestedForDepthCheckTest extends AbstractModuleTestSupport {
    * @throws Exception necessary to fulfill JUnit's interface-requirements for test-methods.
    */
   @Test
-  public void testNestedTooDeep() throws Exception {
+  void nestedTooDeep() throws Exception {
 
     final String[] expected = {
       "32:11: " + getCheckMessage(MSG_KEY, 3, 2),
@@ -60,7 +60,7 @@ public class NestedForDepthCheckTest extends AbstractModuleTestSupport {
    * @throws Exception necessary to fulfill JUnit's interface-requirements for test-methods.
    */
   @Test
-  public void testNestedOk() throws Exception {
+  void nestedOk() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -68,7 +68,7 @@ public class NestedForDepthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final NestedForDepthCheck check = new NestedForDepthCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
@@ -82,7 +82,7 @@ public class NestedForDepthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNestedDefault() throws Exception {
+  void nestedDefault() throws Exception {
     final String[] expected = {
       "27:9: " + getCheckMessage(MSG_KEY, 2, 1),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/NestedIfDepthCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/NestedIfDepthCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class NestedIfDepthCheckTest extends AbstractModuleTestSupport {
+final class NestedIfDepthCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class NestedIfDepthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
 
     final String[] expected = {
       "26:17: " + getCheckMessage(MSG_KEY, 2, 1),
@@ -48,7 +48,7 @@ public class NestedIfDepthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCustomizedDepth() throws Exception {
+  void customizedDepth() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -56,7 +56,7 @@ public class NestedIfDepthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final NestedIfDepthCheck check = new NestedIfDepthCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/NestedTryDepthCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/NestedTryDepthCheckTest.java
@@ -25,7 +25,7 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.NestedTryDepthCheck.
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class NestedTryDepthCheckTest extends AbstractModuleTestSupport {
+final class NestedTryDepthCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class NestedTryDepthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
 
     final String[] expected = {
       "29:17: " + getCheckMessage(MSG_KEY, 2, 1),
@@ -45,7 +45,7 @@ public class NestedTryDepthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCustomizedDepth() throws Exception {
+  void customizedDepth() throws Exception {
 
     final String[] expected = {
       "41:21: " + getCheckMessage(MSG_KEY, 3, 2),
@@ -55,7 +55,7 @@ public class NestedTryDepthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final NestedTryDepthCheck check = new NestedTryDepthCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/NoArrayTrailingCommaCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/NoArrayTrailingCommaCheckTest.java
@@ -25,7 +25,7 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.NoArrayTrailingComma
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class NoArrayTrailingCommaCheckTest extends AbstractModuleTestSupport {
+final class NoArrayTrailingCommaCheckTest extends AbstractModuleTestSupport {
 
   @Override
   public String getPackageLocation() {
@@ -33,7 +33,7 @@ public class NoArrayTrailingCommaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "20:14: " + getCheckMessage(MSG_KEY),
       "25:32: " + getCheckMessage(MSG_KEY),
@@ -47,7 +47,7 @@ public class NoArrayTrailingCommaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final NoArrayTrailingCommaCheck check = new NoArrayTrailingCommaCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/NoCloneCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/NoCloneCheckTest.java
@@ -25,7 +25,7 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.NoCloneCheck.MSG_KEY
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class NoCloneCheckTest extends AbstractModuleTestSupport {
+final class NoCloneCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class NoCloneCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHasClone() throws Exception {
+  void hasClone() throws Exception {
     final String[] expected = {
       "17:5: " + getCheckMessage(MSG_KEY),
       "34:5: " + getCheckMessage(MSG_KEY),
@@ -47,7 +47,7 @@ public class NoCloneCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final NoCloneCheck check = new NoCloneCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/NoEnumTrailingCommaCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/NoEnumTrailingCommaCheckTest.java
@@ -25,7 +25,7 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.NoEnumTrailingCommaC
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class NoEnumTrailingCommaCheckTest extends AbstractModuleTestSupport {
+final class NoEnumTrailingCommaCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class NoEnumTrailingCommaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultOne() throws Exception {
+  void defaultOne() throws Exception {
     final String[] expected = {
       "23:12: " + getCheckMessage(MSG_KEY),
       "28:12: " + getCheckMessage(MSG_KEY),
@@ -48,7 +48,7 @@ public class NoEnumTrailingCommaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultTwo() throws Exception {
+  void defaultTwo() throws Exception {
     final String[] expected = {
       "20:55: " + getCheckMessage(MSG_KEY),
       "24:14: " + getCheckMessage(MSG_KEY),
@@ -64,7 +64,7 @@ public class NoEnumTrailingCommaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultThree() throws Exception {
+  void defaultThree() throws Exception {
     final String[] expected = {
       "13:21: " + getCheckMessage(MSG_KEY),
       "33:10: " + getCheckMessage(MSG_KEY),
@@ -76,7 +76,7 @@ public class NoEnumTrailingCommaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final NoEnumTrailingCommaCheck check = new NoEnumTrailingCommaCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/NoFinalizerCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/NoFinalizerCheckTest.java
@@ -28,7 +28,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
 /** NoFinalizerCheck test. */
-public class NoFinalizerCheckTest extends AbstractModuleTestSupport {
+final class NoFinalizerCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -36,7 +36,7 @@ public class NoFinalizerCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final NoFinalizerCheck noFinalizerCheck = new NoFinalizerCheck();
     final int[] expected = {TokenTypes.METHOD_DEF};
 
@@ -46,7 +46,7 @@ public class NoFinalizerCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHasFinalizer() throws Exception {
+  void hasFinalizer() throws Exception {
     final String[] expected = {
       "11:5: " + getCheckMessage(MSG_KEY),
     };
@@ -54,13 +54,13 @@ public class NoFinalizerCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHasNoFinalizer() throws Exception {
+  void hasNoFinalizer() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputNoFinalizerFallThrough.java"), expected);
   }
 
   @Test
-  public void testHasNoFinalizerTryWithResource() throws Exception {
+  void hasNoFinalizerTryWithResource() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getNonCompilablePath("InputNoFinalizerFallThrough.java"), expected);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/OneStatementPerLineCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/OneStatementPerLineCheckTest.java
@@ -22,13 +22,14 @@ package com.puppycrawl.tools.checkstyle.checks.coding;
 import static com.google.common.truth.Truth.assertWithMessage;
 import static com.puppycrawl.tools.checkstyle.checks.coding.OneStatementPerLineCheck.MSG_KEY;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class OneStatementPerLineCheckTest extends AbstractModuleTestSupport {
+final class OneStatementPerLineCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -36,7 +37,7 @@ public class OneStatementPerLineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMultiCaseClass() throws Exception {
+  void multiCaseClass() throws Exception {
     final String[] expected = {
       "13:59: " + getCheckMessage(MSG_KEY),
       "93:21: " + getCheckMessage(MSG_KEY),
@@ -51,7 +52,7 @@ public class OneStatementPerLineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final OneStatementPerLineCheck check = new OneStatementPerLineCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
@@ -65,7 +66,7 @@ public class OneStatementPerLineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithMultilineStatements() throws Exception {
+  void withMultilineStatements() throws Exception {
     final String[] expected = {
       "49:21: " + getCheckMessage(MSG_KEY),
       "66:17: " + getCheckMessage(MSG_KEY),
@@ -81,7 +82,7 @@ public class OneStatementPerLineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void oneStatementNonCompilableInputTest() throws Exception {
+  void oneStatementNonCompilableInputTest() throws Exception {
     final String[] expected = {
       "39:4: " + getCheckMessage(MSG_KEY),
       "44:54: " + getCheckMessage(MSG_KEY),
@@ -95,7 +96,7 @@ public class OneStatementPerLineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testResourceReferenceVariableIgnored() throws Exception {
+  void resourceReferenceVariableIgnored() throws Exception {
     final String[] expected = {
       "32:42: " + getCheckMessage(MSG_KEY),
       "36:43: " + getCheckMessage(MSG_KEY),
@@ -108,14 +109,14 @@ public class OneStatementPerLineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testResourcesIgnored() throws Exception {
+  void resourcesIgnored() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputOneStatementPerLineTryWithResourcesIgnore.java"), expected);
   }
 
   @Test
-  public void testAllTheCodeInSingleLine() throws Exception {
+  void allTheCodeInSingleLine() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(OneStatementPerLineCheck.class);
 
     final String[] expected = {
@@ -132,22 +133,22 @@ public class OneStatementPerLineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStateIsClearedOnBeginTreeForLastStatementEnd() throws Exception {
+  void stateIsClearedOnBeginTreeForLastStatementEnd() throws Exception {
     final String inputWithWarnings = getPath("InputOneStatementPerLineBeginTree1.java");
     final String inputWithoutWarnings = getPath("InputOneStatementPerLineBeginTree2.java");
-    final List<String> expectedFirstInput = List.of("6:96: " + getCheckMessage(MSG_KEY));
+    final List<String> expectedFirstInput = ImmutableList.of("6:96: " + getCheckMessage(MSG_KEY));
     final List<String> expectedSecondInput = List.of(CommonUtil.EMPTY_STRING_ARRAY);
     verifyWithInlineConfigParser(
         inputWithWarnings, inputWithoutWarnings, expectedFirstInput, expectedSecondInput);
   }
 
   @Test
-  public void testStateIsClearedOnBeginTreeForLastVariableStatement() throws Exception {
+  void stateIsClearedOnBeginTreeForLastVariableStatement() throws Exception {
     final String file1 =
         getPath("InputOneStatementPerLineBeginTreeLastVariableResourcesStatementEnd1.java");
     final String file2 =
         getPath("InputOneStatementPerLineBeginTreeLastVariableResourcesStatementEnd2.java");
-    final List<String> expectedFirstInput = List.of("15:59: " + getCheckMessage(MSG_KEY));
+    final List<String> expectedFirstInput = ImmutableList.of("15:59: " + getCheckMessage(MSG_KEY));
     final List<String> expectedSecondInput = List.of(CommonUtil.EMPTY_STRING_ARRAY);
     verifyWithInlineConfigParser(file1, file2, expectedFirstInput, expectedSecondInput);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/OverloadMethodsDeclarationOrderCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/OverloadMethodsDeclarationOrderCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class OverloadMethodsDeclarationOrderCheckTest extends AbstractModuleTestSupport {
+final class OverloadMethodsDeclarationOrderCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class OverloadMethodsDeclarationOrderCheckTest extends AbstractModuleTest
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
 
     final String[] expected = {
       "32:5: " + getCheckMessage(MSG_KEY, 21),
@@ -46,7 +46,7 @@ public class OverloadMethodsDeclarationOrderCheckTest extends AbstractModuleTest
   }
 
   @Test
-  public void testOverloadMethodsDeclarationOrderRecords() throws Exception {
+  void overloadMethodsDeclarationOrderRecords() throws Exception {
 
     final String[] expected = {
       "21:9: " + getCheckMessage(MSG_KEY, 15),
@@ -58,7 +58,7 @@ public class OverloadMethodsDeclarationOrderCheckTest extends AbstractModuleTest
   }
 
   @Test
-  public void testOverloadMethodsDeclarationOrderPrivateAndStaticMethods() throws Exception {
+  void overloadMethodsDeclarationOrderPrivateAndStaticMethods() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -67,7 +67,7 @@ public class OverloadMethodsDeclarationOrderCheckTest extends AbstractModuleTest
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final OverloadMethodsDeclarationOrderCheck check = new OverloadMethodsDeclarationOrderCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/PackageDeclarationCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/PackageDeclarationCheckTest.java
@@ -31,7 +31,7 @@ import de.thetaphi.forbiddenapis.SuppressForbidden;
 import java.io.File;
 import org.junit.jupiter.api.Test;
 
-public class PackageDeclarationCheckTest extends AbstractModuleTestSupport {
+final class PackageDeclarationCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -39,7 +39,7 @@ public class PackageDeclarationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultNoPackage() throws Exception {
+  void defaultNoPackage() throws Exception {
 
     final String[] expected = {
       "8:1: " + getCheckMessage(MSG_KEY_MISSING),
@@ -49,7 +49,7 @@ public class PackageDeclarationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultWithPackage() throws Exception {
+  void defaultWithPackage() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -57,7 +57,7 @@ public class PackageDeclarationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOnFileWithCommentOnly() throws Exception {
+  void onFileWithCommentOnly() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -65,7 +65,7 @@ public class PackageDeclarationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFileForDiffDirectoryMismatch() throws Exception {
+  void fileForDiffDirectoryMismatch() throws Exception {
 
     final String[] expected = {
       "8:1: " + getCheckMessage(MSG_KEY_MISMATCH),
@@ -76,7 +76,7 @@ public class PackageDeclarationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFileForDirectoryMismatchAtParent() throws Exception {
+  void fileForDirectoryMismatchAtParent() throws Exception {
 
     final String[] expected = {
       "8:1: " + getCheckMessage(MSG_KEY_MISMATCH),
@@ -87,7 +87,7 @@ public class PackageDeclarationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFileForDirectoryMismatchAtSubpackage() throws Exception {
+  void fileForDirectoryMismatchAtSubpackage() throws Exception {
 
     final String[] expected = {
       "8:1: " + getCheckMessage(MSG_KEY_MISMATCH),
@@ -98,7 +98,7 @@ public class PackageDeclarationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFileIgnoreDiffDirectoryMismatch() throws Exception {
+  void fileIgnoreDiffDirectoryMismatch() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -106,7 +106,7 @@ public class PackageDeclarationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFileIgnoreDirectoryMismatchAtParent() throws Exception {
+  void fileIgnoreDirectoryMismatchAtParent() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -114,7 +114,7 @@ public class PackageDeclarationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFileIgnoreDirectoryMismatchAtSubpackage() throws Exception {
+  void fileIgnoreDirectoryMismatchAtSubpackage() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -122,7 +122,7 @@ public class PackageDeclarationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoPackage() throws Exception {
+  void noPackage() throws Exception {
     final String[] expected = {
       "9:1: " + getCheckMessage(MSG_KEY_MISSING),
     };
@@ -133,7 +133,7 @@ public class PackageDeclarationCheckTest extends AbstractModuleTestSupport {
 
   @SuppressForbidden
   @Test
-  public void testEmptyFile() throws Exception {
+  void emptyFile() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(PackageDeclarationCheck.class);
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -141,7 +141,7 @@ public class PackageDeclarationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final PackageDeclarationCheck check = new PackageDeclarationCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
@@ -155,7 +155,7 @@ public class PackageDeclarationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBeginTreeClear() throws Exception {
+  void beginTreeClear() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(PackageDeclarationCheck.class);
     final String[] expected = {
       "8:1: " + getCheckMessage(MSG_KEY_MISSING),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/ParameterAssignmentCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/ParameterAssignmentCheckTest.java
@@ -34,7 +34,7 @@ import java.util.Optional;
 import java.util.Set;
 import org.junit.jupiter.api.Test;
 
-public class ParameterAssignmentCheckTest extends AbstractModuleTestSupport {
+final class ParameterAssignmentCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -42,7 +42,7 @@ public class ParameterAssignmentCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "17:15: " + getCheckMessage(MSG_KEY, "field"),
       "18:15: " + getCheckMessage(MSG_KEY, "field"),
@@ -61,13 +61,13 @@ public class ParameterAssignmentCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testReceiverParameter() throws Exception {
+  void receiverParameter() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputParameterAssignmentReceiver.java"), expected);
   }
 
   @Test
-  public void testEnhancedSwitch() throws Exception {
+  void enhancedSwitch() throws Exception {
     final String[] expected = {
       "14:28: " + getCheckMessage(MSG_KEY, "a"), "21:16: " + getCheckMessage(MSG_KEY, "result"),
     };
@@ -76,7 +76,7 @@ public class ParameterAssignmentCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final ParameterAssignmentCheck check = new ParameterAssignmentCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
@@ -95,9 +95,9 @@ public class ParameterAssignmentCheckTest extends AbstractModuleTestSupport {
    *
    * @throws Exception when code tested throws exception
    */
-  @Test
   @SuppressWarnings("unchecked")
-  public void testClearState() throws Exception {
+  @Test
+  void clearState() throws Exception {
     final ParameterAssignmentCheck check = new ParameterAssignmentCheck();
     final Optional<DetailAST> methodDef =
         TestUtil.findTokenInAstByPredicate(
@@ -111,7 +111,7 @@ public class ParameterAssignmentCheckTest extends AbstractModuleTestSupport {
         .that(
             TestUtil.isStatefulFieldClearedDuringBeginTree(
                 check,
-                methodDef.get(),
+                methodDef.orElseThrow(),
                 "parameterNamesStack",
                 parameterNamesStack -> ((Collection<Set<String>>) parameterNamesStack).isEmpty()))
         .isTrue();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/RequireThisCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/RequireThisCheckTest.java
@@ -39,7 +39,7 @@ import java.util.SortedSet;
 import org.antlr.v4.runtime.CommonToken;
 import org.junit.jupiter.api.Test;
 
-public class RequireThisCheckTest extends AbstractModuleTestSupport {
+final class RequireThisCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -47,7 +47,7 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIt() throws Exception {
+  void it() throws Exception {
     final String[] expected = {
       "20:9: " + getCheckMessage(MSG_VARIABLE, "i", ""),
       "26:9: " + getCheckMessage(MSG_METHOD, "method1", ""),
@@ -73,7 +73,7 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMethodsOnly() throws Exception {
+  void methodsOnly() throws Exception {
     final String[] expected = {
       "25:9: " + getCheckMessage(MSG_METHOD, "method1", ""),
       "124:9: " + getCheckMessage(MSG_METHOD, "instanceMethod", ""),
@@ -85,7 +85,7 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFieldsOnly() throws Exception {
+  void fieldsOnly() throws Exception {
     final String[] expected = {
       "19:9: " + getCheckMessage(MSG_VARIABLE, "i", ""),
       "39:9: " + getCheckMessage(MSG_VARIABLE, "i", ""),
@@ -107,7 +107,7 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFieldsInExpressions() throws Exception {
+  void fieldsInExpressions() throws Exception {
     final String[] expected = {
       "18:28: " + getCheckMessage(MSG_VARIABLE, "id", ""),
       "19:28: " + getCheckMessage(MSG_VARIABLE, "length", ""),
@@ -133,13 +133,13 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGenerics() throws Exception {
+  void generics() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRequireThis15Extensions.java"), expected);
   }
 
   @Test
-  public void testGithubIssue41() throws Exception {
+  void githubIssue41() throws Exception {
     final String[] expected = {
       "16:19: " + getCheckMessage(MSG_VARIABLE, "number", ""),
       "17:16: " + getCheckMessage(MSG_METHOD, "other", ""),
@@ -148,7 +148,7 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final RequireThisCheck check = new RequireThisCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
@@ -162,7 +162,7 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithAnonymousClass() throws Exception {
+  void withAnonymousClass() throws Exception {
     final String[] expected = {
       "29:25: " + getCheckMessage(MSG_METHOD, "doSideEffect", ""),
       "33:24: " + getCheckMessage(MSG_VARIABLE, "bar", "InputRequireThisAnonymousEmpty."),
@@ -172,7 +172,7 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultSwitch() {
+  void defaultSwitch() {
     final RequireThisCheck check = new RequireThisCheck();
 
     final DetailAstImpl ast = new DetailAstImpl();
@@ -185,7 +185,7 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidateOnlyOverlappingFalse() throws Exception {
+  void validateOnlyOverlappingFalse() throws Exception {
     final String[] expected = {
       "29:9: " + getCheckMessage(MSG_VARIABLE, "field1", ""),
       "30:9: " + getCheckMessage(MSG_VARIABLE, "fieldFinal1", ""),
@@ -238,7 +238,7 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidateOnlyOverlappingFalseLeaves() throws Exception {
+  void validateOnlyOverlappingFalseLeaves() throws Exception {
     final String[] expected = {
       "26:31: " + getCheckMessage(MSG_METHOD, "id", ""),
       "36:16: " + getCheckMessage(MSG_VARIABLE, "_a", ""),
@@ -248,7 +248,7 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidateOnlyOverlappingTrue() throws Exception {
+  void validateOnlyOverlappingTrue() throws Exception {
     final String[] expected = {
       "29:9: " + getCheckMessage(MSG_VARIABLE, "field1", ""),
       "52:9: " + getCheckMessage(MSG_VARIABLE, "field1", ""),
@@ -268,32 +268,32 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidateOnlyOverlappingTrue2() throws Exception {
+  void validateOnlyOverlappingTrue2() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputRequireThisValidateOnlyOverlappingTrue2.java"), expected);
   }
 
   @Test
-  public void testReceiverParameter() throws Exception {
+  void receiverParameter() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRequireThisReceiver.java"), expected);
   }
 
   @Test
-  public void testBraceAlone() throws Exception {
+  void braceAlone() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRequireThisBraceAlone.java"), expected);
   }
 
   @Test
-  public void testStatic() throws Exception {
+  void testStatic() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRequireThisStatic.java"), expected);
   }
 
   @Test
-  public void testMethodReferences() throws Exception {
+  void methodReferences() throws Exception {
     final String[] expected = {
       "24:9: " + getCheckMessage(MSG_VARIABLE, "tags", ""),
     };
@@ -301,7 +301,7 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowLocalVars() throws Exception {
+  void allowLocalVars() throws Exception {
     final String[] expected = {
       "18:9: " + getCheckMessage(MSG_VARIABLE, "s1", ""),
       "26:9: " + getCheckMessage(MSG_VARIABLE, "s1", ""),
@@ -314,7 +314,7 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowLambdaParameters() throws Exception {
+  void allowLambdaParameters() throws Exception {
     final String[] expected = {
       "24:9: " + getCheckMessage(MSG_VARIABLE, "s1", ""),
       "46:21: " + getCheckMessage(MSG_VARIABLE, "z", ""),
@@ -326,13 +326,13 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTryWithResources() throws Exception {
+  void tryWithResources() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRequireThisTryWithResources.java"), expected);
   }
 
   @Test
-  public void testTryWithResourcesOnlyOverlappingFalse() throws Exception {
+  void tryWithResourcesOnlyOverlappingFalse() throws Exception {
     final String[] expected = {
       "44:23: " + getCheckMessage(MSG_VARIABLE, "fldCharset", ""),
       "57:13: " + getCheckMessage(MSG_VARIABLE, "fldCharset", ""),
@@ -350,7 +350,7 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCatchVariables() throws Exception {
+  void catchVariables() throws Exception {
     final String[] expected = {
       "38:21: " + getCheckMessage(MSG_VARIABLE, "ex", ""),
     };
@@ -358,19 +358,19 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEnumConstant() throws Exception {
+  void enumConstant() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRequireThisEnumConstant.java"), expected);
   }
 
   @Test
-  public void testAnnotationInterface() throws Exception {
+  void annotationInterface() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRequireThisAnnotationInterface.java"), expected);
   }
 
   @Test
-  public void testFor() throws Exception {
+  void testFor() throws Exception {
     final String[] expected = {
       "22:13: " + getCheckMessage(MSG_VARIABLE, "bottom", ""),
       "30:34: " + getCheckMessage(MSG_VARIABLE, "name", ""),
@@ -379,7 +379,7 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFinalInstanceVariable() throws Exception {
+  void finalInstanceVariable() throws Exception {
     final String[] expected = {
       "18:9: " + getCheckMessage(MSG_VARIABLE, "y", ""),
       "19:9: " + getCheckMessage(MSG_VARIABLE, "z", ""),
@@ -388,13 +388,13 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test() throws Exception {
+  void test() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRequireThisCaseGroup.java"), expected);
   }
 
   @Test
-  public void testExtendedMethod() throws Exception {
+  void extendedMethod() throws Exception {
     final String[] expected = {
       "31:9: " + getCheckMessage(MSG_VARIABLE, "EXPR", ""),
     };
@@ -402,7 +402,7 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRecordsAndCompactCtors() throws Exception {
+  void recordsAndCompactCtors() throws Exception {
     final String[] expected = {
       "18:13: " + getCheckMessage(MSG_METHOD, "method1", ""),
       "19:13: " + getCheckMessage(MSG_METHOD, "method2", ""),
@@ -418,14 +418,14 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRecordCompactCtors() throws Exception {
+  void recordCompactCtors() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getNonCompilablePath("InputRequireThisRecordCompactCtors.java"), expected);
   }
 
   @Test
-  public void testRecordsAsTopLevel() throws Exception {
+  void recordsAsTopLevel() throws Exception {
     final String[] expected = {
       "17:9: " + getCheckMessage(MSG_METHOD, "method1", ""),
       "18:9: " + getCheckMessage(MSG_METHOD, "method2", ""),
@@ -440,7 +440,7 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRecordsDefault() throws Exception {
+  void recordsDefault() throws Exception {
     final String[] expected = {
       "26:9: " + getCheckMessage(MSG_VARIABLE, "x", ""),
     };
@@ -449,14 +449,14 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRecordsWithCheckFields() throws Exception {
+  void recordsWithCheckFields() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getNonCompilablePath("InputRequireThisRecordsWithCheckFields.java"), expected);
   }
 
   @Test
-  public void testRecordsWithCheckFieldsOverlap() throws Exception {
+  void recordsWithCheckFieldsOverlap() throws Exception {
     final String[] expected = {
       "20:20: " + getCheckMessage(MSG_VARIABLE, "a", ""),
       "39:20: " + getCheckMessage(MSG_VARIABLE, "a", ""),
@@ -467,7 +467,7 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLocalClassesInsideLambdas() throws Exception {
+  void localClassesInsideLambdas() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputRequireThisLocalClassesInsideLambdas.java"), expected);
@@ -480,7 +480,7 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
    * @throws Exception when code tested throws an exception.
    */
   @Test
-  public void testUnusedMethodCatch() throws Exception {
+  void unusedMethodCatch() throws Exception {
     final DetailAstImpl ident = new DetailAstImpl();
     ident.setText("testName");
 
@@ -503,7 +503,7 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
    * @throws Exception when code tested throws an exception.
    */
   @Test
-  public void testUnusedMethodFor() throws Exception {
+  void unusedMethodFor() throws Exception {
     final DetailAstImpl ident = new DetailAstImpl();
     ident.setText("testName");
 
@@ -524,7 +524,7 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
    * @throws Exception when code tested throws exception
    */
   @Test
-  public void testClearState() throws Exception {
+  void clearState() throws Exception {
     final RequireThisCheck check = new RequireThisCheck();
     final DetailAST root =
         JavaParser.parseFile(
@@ -536,7 +536,10 @@ public class RequireThisCheckTest extends AbstractModuleTestSupport {
     assertWithMessage("State is not cleared on beginTree")
         .that(
             TestUtil.isStatefulFieldClearedDuringBeginTree(
-                check, classDef.get(), "current", current -> ((Collection<?>) current).isEmpty()))
+                check,
+                classDef.orElseThrow(),
+                "current",
+                current -> ((Collection<?>) current).isEmpty()))
         .isTrue();
   }
 }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/ReturnCountCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/ReturnCountCheckTest.java
@@ -37,7 +37,7 @@ import java.util.Optional;
 import java.util.Set;
 import org.junit.jupiter.api.Test;
 
-public class ReturnCountCheckTest extends AbstractModuleTestSupport {
+final class ReturnCountCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -45,7 +45,7 @@ public class ReturnCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "28:5: " + getCheckMessage(MSG_KEY_VOID, 7, 1),
       "40:5: " + getCheckMessage(MSG_KEY_VOID, 2, 1),
@@ -56,7 +56,7 @@ public class ReturnCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFormat() throws Exception {
+  void format() throws Exception {
     final String[] expected = {
       "15:5: " + getCheckMessage(MSG_KEY, 7, 2),
       "28:5: " + getCheckMessage(MSG_KEY_VOID, 7, 1),
@@ -68,7 +68,7 @@ public class ReturnCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMethodsAndLambdas() throws Exception {
+  void methodsAndLambdas() throws Exception {
     final String[] expected = {
       "25:55: " + getCheckMessage(MSG_KEY, 2, 1),
       "37:49: " + getCheckMessage(MSG_KEY, 2, 1),
@@ -80,7 +80,7 @@ public class ReturnCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLambdasOnly() throws Exception {
+  void lambdasOnly() throws Exception {
     final String[] expected = {
       "43:42: " + getCheckMessage(MSG_KEY, 3, 2),
     };
@@ -88,7 +88,7 @@ public class ReturnCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMethodsOnly() throws Exception {
+  void methodsOnly() throws Exception {
     final String[] expected = {
       "35:5: " + getCheckMessage(MSG_KEY, 3, 2),
       "42:5: " + getCheckMessage(MSG_KEY, 4, 2),
@@ -99,13 +99,13 @@ public class ReturnCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithReturnOnlyAsTokens() throws Exception {
+  void withReturnOnlyAsTokens() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputReturnCountLambda4.java"), expected);
   }
 
   @Test
-  public void testImproperToken() {
+  void improperToken() {
     final ReturnCountCheck check = new ReturnCountCheck();
 
     final DetailAstImpl classDefAst = new DetailAstImpl();
@@ -127,7 +127,7 @@ public class ReturnCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMaxForVoid() throws Exception {
+  void maxForVoid() throws Exception {
     final String[] expected = {
       "14:5: " + getCheckMessage(MSG_KEY_VOID, 1, 0),
       "18:5: " + getCheckMessage(MSG_KEY_VOID, 1, 0),
@@ -144,9 +144,9 @@ public class ReturnCountCheckTest extends AbstractModuleTestSupport {
    *
    * @throws Exception when code tested throws exception
    */
-  @Test
   @SuppressWarnings("unchecked")
-  public void testClearState() throws Exception {
+  @Test
+  void clearState() throws Exception {
     final ReturnCountCheck check = new ReturnCountCheck();
     final Optional<DetailAST> methodDef =
         TestUtil.findTokenInAstByPredicate(
@@ -160,7 +160,7 @@ public class ReturnCountCheckTest extends AbstractModuleTestSupport {
         .that(
             TestUtil.isStatefulFieldClearedDuringBeginTree(
                 check,
-                methodDef.get(),
+                methodDef.orElseThrow(),
                 "contextStack",
                 contextStack -> ((Collection<Set<String>>) contextStack).isEmpty()))
         .isTrue();
@@ -172,7 +172,7 @@ public class ReturnCountCheckTest extends AbstractModuleTestSupport {
    * beneficial.
    */
   @Test
-  public void testImproperVisitToken() {
+  void improperVisitToken() {
     final ReturnCountCheck check = new ReturnCountCheck();
     final DetailAstImpl classDefAst = new DetailAstImpl();
     classDefAst.setType(TokenTypes.CLASS_DEF);
@@ -193,7 +193,7 @@ public class ReturnCountCheckTest extends AbstractModuleTestSupport {
    * beneficial.
    */
   @Test
-  public void testImproperLeaveToken() {
+  void improperLeaveToken() {
     final ReturnCountCheck check = new ReturnCountCheck();
     final DetailAstImpl classDefAst = new DetailAstImpl();
     classDefAst.setType(TokenTypes.CLASS_DEF);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/SimplifyBooleanExpressionCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/SimplifyBooleanExpressionCheckTest.java
@@ -25,7 +25,7 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.SimplifyBooleanExpre
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class SimplifyBooleanExpressionCheckTest extends AbstractModuleTestSupport {
+final class SimplifyBooleanExpressionCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class SimplifyBooleanExpressionCheckTest extends AbstractModuleTestSuppor
   }
 
   @Test
-  public void testIt() throws Exception {
+  void it() throws Exception {
     final String[] expected = {
       "22:18: " + getCheckMessage(MSG_KEY),
       "43:36: " + getCheckMessage(MSG_KEY),
@@ -53,7 +53,7 @@ public class SimplifyBooleanExpressionCheckTest extends AbstractModuleTestSuppor
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final SimplifyBooleanExpressionCheck check = new SimplifyBooleanExpressionCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/SimplifyBooleanReturnCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/SimplifyBooleanReturnCheckTest.java
@@ -25,7 +25,7 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.SimplifyBooleanRetur
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class SimplifyBooleanReturnCheckTest extends AbstractModuleTestSupport {
+final class SimplifyBooleanReturnCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class SimplifyBooleanReturnCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIt() throws Exception {
+  void it() throws Exception {
     final String[] expected = {
       "22:9: " + getCheckMessage(MSG_KEY), "35:9: " + getCheckMessage(MSG_KEY),
     };
@@ -41,7 +41,7 @@ public class SimplifyBooleanReturnCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final SimplifyBooleanReturnCheck check = new SimplifyBooleanReturnCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/StringLiteralEqualityCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/StringLiteralEqualityCheckTest.java
@@ -25,7 +25,7 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.StringLiteralEqualit
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class StringLiteralEqualityCheckTest extends AbstractModuleTestSupport {
+final class StringLiteralEqualityCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class StringLiteralEqualityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIt() throws Exception {
+  void it() throws Exception {
     final String[] expected = {
       "17:18: " + getCheckMessage(MSG_KEY, "=="),
       "22:20: " + getCheckMessage(MSG_KEY, "=="),
@@ -43,7 +43,7 @@ public class StringLiteralEqualityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStringLiteralEqualityTextBlocks() throws Exception {
+  void stringLiteralEqualityTextBlocks() throws Exception {
     final String[] expected = {
       "14:34: " + getCheckMessage(MSG_KEY, "=="),
       "22:21: " + getCheckMessage(MSG_KEY, "=="),
@@ -55,7 +55,7 @@ public class StringLiteralEqualityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testConcatenatedStringLiterals() throws Exception {
+  void concatenatedStringLiterals() throws Exception {
     final String[] expected = {
       "14:15: " + getCheckMessage(MSG_KEY, "=="),
       "17:24: " + getCheckMessage(MSG_KEY, "=="),
@@ -74,7 +74,7 @@ public class StringLiteralEqualityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testConcatenatedTextBlocks() throws Exception {
+  void concatenatedTextBlocks() throws Exception {
     final String[] expected = {
       "15:15: " + getCheckMessage(MSG_KEY, "=="),
       "21:23: " + getCheckMessage(MSG_KEY, "=="),
@@ -91,7 +91,7 @@ public class StringLiteralEqualityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test() throws Exception {
+  void test() throws Exception {
     final String[] expected = {
       "32:24: " + getCheckMessage(MSG_KEY, "=="),
     };
@@ -99,7 +99,7 @@ public class StringLiteralEqualityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final StringLiteralEqualityCheck check = new StringLiteralEqualityCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/SuperCloneCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/SuperCloneCheckTest.java
@@ -34,7 +34,7 @@ import java.util.Optional;
 import java.util.Set;
 import org.junit.jupiter.api.Test;
 
-public class SuperCloneCheckTest extends AbstractModuleTestSupport {
+final class SuperCloneCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -42,7 +42,7 @@ public class SuperCloneCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIt() throws Exception {
+  void it() throws Exception {
     final String[] expected = {
       "33:19: " + getCheckMessage(MSG_KEY, "clone", "super.clone"),
       "41:19: " + getCheckMessage(MSG_KEY, "clone", "super.clone"),
@@ -52,7 +52,7 @@ public class SuperCloneCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnotherInputFile() throws Exception {
+  void anotherInputFile() throws Exception {
     final String[] expected = {
       "14:17: " + getCheckMessage(MSG_KEY, "clone", "super.clone"),
       "48:17: " + getCheckMessage(MSG_KEY, "clone", "super.clone"),
@@ -61,13 +61,13 @@ public class SuperCloneCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMethodReference() throws Exception {
+  void methodReference() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputSuperCloneMethodReference.java"), expected);
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final SuperCloneCheck check = new SuperCloneCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
@@ -86,9 +86,9 @@ public class SuperCloneCheckTest extends AbstractModuleTestSupport {
    *
    * @throws Exception when code tested throws exception
    */
-  @Test
   @SuppressWarnings("unchecked")
-  public void testClearState() throws Exception {
+  @Test
+  void clearState() throws Exception {
     final AbstractSuperCheck check = new SuperCloneCheck();
     final Optional<DetailAST> methodDef =
         TestUtil.findTokenInAstByPredicate(
@@ -102,7 +102,7 @@ public class SuperCloneCheckTest extends AbstractModuleTestSupport {
         .that(
             TestUtil.isStatefulFieldClearedDuringBeginTree(
                 check,
-                methodDef.get(),
+                methodDef.orElseThrow(),
                 "methodStack",
                 methodStack -> ((Collection<Set<String>>) methodStack).isEmpty()))
         .isTrue();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/SuperFinalizeCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/SuperFinalizeCheckTest.java
@@ -24,7 +24,7 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.AbstractSuperCheck.M
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class SuperFinalizeCheckTest extends AbstractModuleTestSupport {
+final class SuperFinalizeCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class SuperFinalizeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIt() throws Exception {
+  void it() throws Exception {
     final String[] expected = {
       "34:17: " + getCheckMessage(MSG_KEY, "finalize", "super.finalize"),
       "41:17: " + getCheckMessage(MSG_KEY, "finalize", "super.finalize"),
@@ -42,7 +42,7 @@ public class SuperFinalizeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMethodReference() throws Exception {
+  void methodReference() throws Exception {
     final String[] expected = {
       "23:20: " + getCheckMessage(MSG_KEY, "finalize", "super.finalize"),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessaryParenthesesCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessaryParenthesesCheckTest.java
@@ -33,7 +33,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
 /** Test fixture for the UnnecessaryParenthesesCheck. */
-public class UnnecessaryParenthesesCheckTest extends AbstractModuleTestSupport {
+final class UnnecessaryParenthesesCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -41,7 +41,7 @@ public class UnnecessaryParenthesesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
 
     final String[] expected = {
       "18:22: " + getCheckMessage(MSG_ASSIGN),
@@ -97,7 +97,7 @@ public class UnnecessaryParenthesesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test15Extensions() throws Exception {
+  void test15Extensions() throws Exception {
     final String[] expected = {
       "28:23: " + getCheckMessage(MSG_EXPR),
       "28:51: " + getCheckMessage(MSG_LITERAL, "1"),
@@ -107,7 +107,7 @@ public class UnnecessaryParenthesesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLambdas() throws Exception {
+  void lambdas() throws Exception {
     final String[] expected = {
       "17:35: " + getCheckMessage(MSG_LAMBDA),
       "18:35: " + getCheckMessage(MSG_LAMBDA),
@@ -122,7 +122,7 @@ public class UnnecessaryParenthesesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testReturn() throws Exception {
+  void testReturn() throws Exception {
     final String[] expected = {
       "21:33: " + getCheckMessage(MSG_RETURN),
       "22:16: " + getCheckMessage(MSG_RETURN),
@@ -135,7 +135,7 @@ public class UnnecessaryParenthesesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUnnecessaryParenthesesSwitchExpression() throws Exception {
+  void unnecessaryParenthesesSwitchExpression() throws Exception {
     final String[] expected = {
       "21:31: " + getCheckMessage(MSG_ASSIGN),
       "24:13: " + getCheckMessage(MSG_LITERAL, 2),
@@ -154,7 +154,7 @@ public class UnnecessaryParenthesesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUnnecessaryParenthesesTextBlocks() throws Exception {
+  void unnecessaryParenthesesTextBlocks() throws Exception {
     final String[] expected = {
       "19:23: " + getCheckMessage(MSG_STRING, "\"this\""),
       "19:34: " + getCheckMessage(MSG_STRING, "\"that\""),
@@ -170,14 +170,14 @@ public class UnnecessaryParenthesesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUnnecessaryParenthesesPatterns() throws Exception {
+  void unnecessaryParenthesesPatterns() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getNonCompilablePath("InputUnnecessaryParenthesesCheckPatterns.java"), expected);
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final UnnecessaryParenthesesCheck check = new UnnecessaryParenthesesCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
@@ -191,7 +191,7 @@ public class UnnecessaryParenthesesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIfStatement() throws Exception {
+  void ifStatement() throws Exception {
 
     final String[] expected = {
       "20:20: " + getCheckMessage(MSG_EXPR),
@@ -225,7 +225,7 @@ public class UnnecessaryParenthesesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIfStatement2() throws Exception {
+  void ifStatement2() throws Exception {
     final String[] expected = {
       "28:17: " + getCheckMessage(MSG_EXPR),
       "39:17: " + getCheckMessage(MSG_EXPR),
@@ -241,7 +241,7 @@ public class UnnecessaryParenthesesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIdentifier() throws Exception {
+  void identifier() throws Exception {
     final String[] expected = {
       "22:17: " + getCheckMessage(MSG_IDENT, "test"),
       "31:18: " + getCheckMessage(MSG_ASSIGN),
@@ -259,7 +259,7 @@ public class UnnecessaryParenthesesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOperator1() throws Exception {
+  void operator1() throws Exception {
     final String[] expected = {
       "20:17: " + getCheckMessage(MSG_EXPR),
       "22:17: " + getCheckMessage(MSG_EXPR),
@@ -293,7 +293,7 @@ public class UnnecessaryParenthesesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOperator2() throws Exception {
+  void operator2() throws Exception {
     final String[] expected = {
       "66:18: " + getCheckMessage(MSG_EXPR),
       "67:17: " + getCheckMessage(MSG_EXPR),
@@ -311,7 +311,7 @@ public class UnnecessaryParenthesesCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOperator3() throws Exception {
+  void operator3() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputUnnecessaryParenthesesOperator3.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessarySemicolonAfterOuterTypeDeclarationCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessarySemicolonAfterOuterTypeDeclarationCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class UnnecessarySemicolonAfterOuterTypeDeclarationCheckTest
+final class UnnecessarySemicolonAfterOuterTypeDeclarationCheckTest
     extends AbstractModuleTestSupport {
 
   @Override
@@ -37,7 +37,7 @@ public class UnnecessarySemicolonAfterOuterTypeDeclarationCheckTest
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
 
     final String[] expected = {
       "28:2: " + getCheckMessage(MSG_SEMI),
@@ -51,7 +51,7 @@ public class UnnecessarySemicolonAfterOuterTypeDeclarationCheckTest
   }
 
   @Test
-  public void testUnnecessarySemicolonAfterOuterTypeDeclarationRecords() throws Exception {
+  void unnecessarySemicolonAfterOuterTypeDeclarationRecords() throws Exception {
 
     final String[] expected = {
       "17:2: " + getCheckMessage(MSG_SEMI), "23:2: " + getCheckMessage(MSG_SEMI),
@@ -63,7 +63,7 @@ public class UnnecessarySemicolonAfterOuterTypeDeclarationCheckTest
   }
 
   @Test
-  public void testTokens() {
+  void tokens() {
     final UnnecessarySemicolonAfterOuterTypeDeclarationCheck check =
         new UnnecessarySemicolonAfterOuterTypeDeclarationCheck();
     final int[] expected = {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessarySemicolonAfterTypeMemberDeclarationCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessarySemicolonAfterTypeMemberDeclarationCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class UnnecessarySemicolonAfterTypeMemberDeclarationCheckTest
+final class UnnecessarySemicolonAfterTypeMemberDeclarationCheckTest
     extends AbstractModuleTestSupport {
 
   @Override
@@ -37,7 +37,7 @@ public class UnnecessarySemicolonAfterTypeMemberDeclarationCheckTest
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
 
     final String[] expected = {
       "13:5: " + getCheckMessage(MSG_SEMI),
@@ -61,7 +61,7 @@ public class UnnecessarySemicolonAfterTypeMemberDeclarationCheckTest
   }
 
   @Test
-  public void testUnnecessarySemicolonAfterTypeMemberDeclarationRecords() throws Exception {
+  void unnecessarySemicolonAfterTypeMemberDeclarationRecords() throws Exception {
 
     final String[] expected = {
       "14:5: " + getCheckMessage(MSG_SEMI),
@@ -79,7 +79,7 @@ public class UnnecessarySemicolonAfterTypeMemberDeclarationCheckTest
   }
 
   @Test
-  public void testTokens() {
+  void tokens() {
     final UnnecessarySemicolonAfterTypeMemberDeclarationCheck check =
         new UnnecessarySemicolonAfterTypeMemberDeclarationCheck();
     final int[] expected = {
@@ -109,7 +109,7 @@ public class UnnecessarySemicolonAfterTypeMemberDeclarationCheckTest
   }
 
   @Test
-  public void testIsSemicolonWithNullAst() throws Exception {
+  void isSemicolonWithNullAst() throws Exception {
     final String[] expected = {"24:32: " + getCheckMessage(MSG_SEMI)};
 
     verifyWithInlineConfigParser(
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessarySemicolonInEnumerationCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessarySemicolonInEnumerationCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
 /** Test fixture for the UnnecessarySemicolonInEnumerationCheck. */
-public class UnnecessarySemicolonInEnumerationCheckTest extends AbstractModuleTestSupport {
+final class UnnecessarySemicolonInEnumerationCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class UnnecessarySemicolonInEnumerationCheckTest extends AbstractModuleTe
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
 
     final String[] expected = {
       "30:12: " + getCheckMessage(MSG_SEMI),
@@ -55,7 +55,7 @@ public class UnnecessarySemicolonInEnumerationCheckTest extends AbstractModuleTe
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final UnnecessarySemicolonInEnumerationCheck check =
         new UnnecessarySemicolonInEnumerationCheck();
     final int[] expected = {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessarySemicolonInTryWithResourcesCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessarySemicolonInTryWithResourcesCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class UnnecessarySemicolonInTryWithResourcesCheckTest extends AbstractModuleTestSupport {
+final class UnnecessarySemicolonInTryWithResourcesCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class UnnecessarySemicolonInTryWithResourcesCheckTest extends AbstractMod
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
 
     final String[] expected = {
       "17:42: " + getCheckMessage(MSG_SEMI), "18:72: " + getCheckMessage(MSG_SEMI),
@@ -46,7 +46,7 @@ public class UnnecessarySemicolonInTryWithResourcesCheckTest extends AbstractMod
   }
 
   @Test
-  public void testNoBraceAfterAllowed() throws Exception {
+  void noBraceAfterAllowed() throws Exception {
     final String[] expected = {
       "16:42: " + getCheckMessage(MSG_SEMI),
       "19:13: " + getCheckMessage(MSG_SEMI),
@@ -58,7 +58,7 @@ public class UnnecessarySemicolonInTryWithResourcesCheckTest extends AbstractMod
   }
 
   @Test
-  public void testTokensAreCorrect() {
+  void tokensAreCorrect() {
     final UnnecessarySemicolonInTryWithResourcesCheck check =
         new UnnecessarySemicolonInTryWithResourcesCheck();
     final int[] expected = {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/UnusedLocalVariableCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/UnusedLocalVariableCheckTest.java
@@ -36,7 +36,7 @@ import java.util.Optional;
 import java.util.function.Predicate;
 import org.junit.jupiter.api.Test;
 
-public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
+final class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -44,7 +44,7 @@ public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final UnusedLocalVariableCheck checkObj = new UnusedLocalVariableCheck();
     final int[] actual = checkObj.getRequiredTokens();
     final int[] expected = {
@@ -73,7 +73,7 @@ public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final UnusedLocalVariableCheck typeParameterNameCheckObj = new UnusedLocalVariableCheck();
     final int[] actual = typeParameterNameCheckObj.getAcceptableTokens();
     final int[] expected = {
@@ -102,7 +102,7 @@ public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUnusedLocalVariable() throws Exception {
+  void unusedLocalVariable() throws Exception {
     final String[] expected = {
       "27:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "sameName"),
       "28:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "b"),
@@ -122,7 +122,7 @@ public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUnusedLocalVar2() throws Exception {
+  void unusedLocalVar2() throws Exception {
     final String[] expected = {
       "17:14: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "i"),
       "19:14: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "j"),
@@ -138,7 +138,7 @@ public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUnusedLocalVarInAnonInnerClasses() throws Exception {
+  void unusedLocalVarInAnonInnerClasses() throws Exception {
     final String[] expected = {
       "14:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "a"),
       "15:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "b"),
@@ -155,7 +155,7 @@ public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUnusedLocalVarGenericAnonInnerClasses() throws Exception {
+  void unusedLocalVarGenericAnonInnerClasses() throws Exception {
     final String[] expected = {
       "13:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "l"),
       "14:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "obj"),
@@ -171,7 +171,7 @@ public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUnusedLocalVarDepthOfClasses() throws Exception {
+  void unusedLocalVarDepthOfClasses() throws Exception {
     final String[] expected = {
       "28:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "r"),
       "49:21: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "a"),
@@ -182,7 +182,7 @@ public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUnusedLocalVarNestedClasses() throws Exception {
+  void unusedLocalVarNestedClasses() throws Exception {
     final String[] expected = {
       "21:13: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "V"),
       "23:13: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "S"),
@@ -196,7 +196,7 @@ public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUnusedLocalVarNestedClasses2() throws Exception {
+  void unusedLocalVarNestedClasses2() throws Exception {
     final String[] expected = {
       "29:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "q"),
       "30:51: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "obj"),
@@ -208,7 +208,7 @@ public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUnusedLocalVarNestedClasses3() throws Exception {
+  void unusedLocalVarNestedClasses3() throws Exception {
     final String[] expected = {
       "36:17: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "p2"),
       "54:13: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "o"),
@@ -220,7 +220,7 @@ public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUnusedLocalVarTestWarningSeverity() throws Exception {
+  void unusedLocalVarTestWarningSeverity() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -228,7 +228,7 @@ public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUnusedLocalVarEnum() throws Exception {
+  void unusedLocalVarEnum() throws Exception {
     final String[] expected = {
       "22:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "a"),
       "50:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "a"),
@@ -240,7 +240,7 @@ public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUnusedLocalVarRecords() throws Exception {
+  void unusedLocalVarRecords() throws Exception {
     final String[] expected = {
       "16:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "var1"),
       "25:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "var1"),
@@ -252,7 +252,7 @@ public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUnusedLocalVarWithoutPackageStatement() throws Exception {
+  void unusedLocalVarWithoutPackageStatement() throws Exception {
     final String[] expected = {
       "12:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "a"),
       "24:9: " + getCheckMessage(MSG_UNUSED_LOCAL_VARIABLE, "var2"),
@@ -263,14 +263,14 @@ public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUnusedLocalVariableTernaryAndExpressions() throws Exception {
+  void unusedLocalVariableTernaryAndExpressions() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputUnusedLocalVariableTernaryAndExpressions.java"), expected);
   }
 
   @Test
-  public void testClearStateVariables() throws Exception {
+  void clearStateVariables() throws Exception {
     final UnusedLocalVariableCheck check = new UnusedLocalVariableCheck();
     final Optional<DetailAST> methodDef =
         TestUtil.findTokenInAstByPredicate(
@@ -280,7 +280,7 @@ public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
             ast -> ast.getType() == TokenTypes.METHOD_DEF);
     assertWithMessage("Ast should contain METHOD_DEF").that(methodDef.isPresent()).isTrue();
     final DetailAST variableDef =
-        methodDef.get().getLastChild().findFirstToken(TokenTypes.VARIABLE_DEF);
+        methodDef.orElseThrow().getLastChild().findFirstToken(TokenTypes.VARIABLE_DEF);
     assertWithMessage("State is not cleared on beginTree")
         .that(
             TestUtil.isStatefulFieldClearedDuringBeginTree(
@@ -294,7 +294,7 @@ public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClearStateClasses() throws Exception {
+  void clearStateClasses() throws Exception {
     final UnusedLocalVariableCheck check = new UnusedLocalVariableCheck();
     final Optional<DetailAST> classDef =
         TestUtil.findTokenInAstByPredicate(
@@ -303,7 +303,7 @@ public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
                 JavaParser.Options.WITHOUT_COMMENTS),
             ast -> ast.getType() == TokenTypes.CLASS_DEF);
     assertWithMessage("Ast should contain CLASS_DEF").that(classDef.isPresent()).isTrue();
-    final DetailAST classDefToken = classDef.get();
+    final DetailAST classDefToken = classDef.orElseThrow();
     assertWithMessage("State is not cleared on beginTree")
         .that(
             TestUtil.isStatefulFieldClearedDuringBeginTree(
@@ -337,7 +337,7 @@ public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClearStateAnonInnerClass() throws Exception {
+  void clearStateAnonInnerClass() throws Exception {
     final UnusedLocalVariableCheck check = new UnusedLocalVariableCheck();
     final DetailAST root =
         JavaParser.parseFile(
@@ -351,7 +351,7 @@ public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
     assertWithMessage("Ast should contain LITERAL_NEW").that(literalNew.isPresent()).isTrue();
     check.beginTree(root);
     check.visitToken(classDefAst);
-    check.visitToken(literalNew.get());
+    check.visitToken(literalNew.orElseThrow());
     check.beginTree(null);
     final Predicate<Object> isClear =
         anonInnerAstToTypeDesc -> {
@@ -370,7 +370,7 @@ public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClearStatePackageDef() throws Exception {
+  void clearStatePackageDef() throws Exception {
     final UnusedLocalVariableCheck check = new UnusedLocalVariableCheck();
     final Optional<DetailAST> packageDef =
         TestUtil.findTokenInAstByPredicate(
@@ -379,7 +379,7 @@ public class UnusedLocalVariableCheckTest extends AbstractModuleTestSupport {
                 JavaParser.Options.WITHOUT_COMMENTS),
             ast -> ast.getType() == TokenTypes.PACKAGE_DEF);
     assertWithMessage("Ast should contain PACKAGE_DEF").that(packageDef.isPresent()).isTrue();
-    final DetailAST packageDefToken = packageDef.get();
+    final DetailAST packageDefToken = packageDef.orElseThrow();
     assertWithMessage("State is not cleared on beginTree")
         .that(
             TestUtil.isStatefulFieldClearedDuringBeginTree(
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/VariableDeclarationUsageDistanceCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/VariableDeclarationUsageDistanceCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class VariableDeclarationUsageDistanceCheckTest extends AbstractModuleTestSupport {
+final class VariableDeclarationUsageDistanceCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class VariableDeclarationUsageDistanceCheckTest extends AbstractModuleTes
   }
 
   @Test
-  public void testGeneralLogic() throws Exception {
+  void generalLogic() throws Exception {
     final String[] expected = {
       "42:9: " + getCheckMessage(MSG_KEY, "a", 2, 1),
       "50:9: " + getCheckMessage(MSG_KEY, "temp", 2, 1),
@@ -79,7 +79,7 @@ public class VariableDeclarationUsageDistanceCheckTest extends AbstractModuleTes
   }
 
   @Test
-  public void testGeneralLogic2() throws Exception {
+  void generalLogic2() throws Exception {
     final String[] expected = {
       "17:9: " + getCheckMessage(MSG_KEY, "first", 5, 1),
       "29:9: " + getCheckMessage(MSG_KEY, "allInvariants", 2, 1),
@@ -89,7 +89,7 @@ public class VariableDeclarationUsageDistanceCheckTest extends AbstractModuleTes
   }
 
   @Test
-  public void testIfStatements() throws Exception {
+  void ifStatements() throws Exception {
     final String[] expected = {
       "18:9: " + getCheckMessage(MSG_KEY, "a", 4, 1),
       "28:9: " + getCheckMessage(MSG_KEY, "a", 2, 1),
@@ -105,7 +105,7 @@ public class VariableDeclarationUsageDistanceCheckTest extends AbstractModuleTes
   }
 
   @Test
-  public void testDistance() throws Exception {
+  void distance() throws Exception {
     final String[] expected = {
       "83:9: " + getCheckMessage(MSG_KEY, "count", 4, 3),
       "231:9: " + getCheckMessage(MSG_KEY, "t", 5, 3),
@@ -121,7 +121,7 @@ public class VariableDeclarationUsageDistanceCheckTest extends AbstractModuleTes
   }
 
   @Test
-  public void testVariableRegExp() throws Exception {
+  void variableRegExp() throws Exception {
     final String[] expected = {
       "50:9: " + getCheckMessage(MSG_KEY, "temp", 2, 1),
       "56:9: " + getCheckMessage(MSG_KEY, "temp", 2, 1),
@@ -154,7 +154,7 @@ public class VariableDeclarationUsageDistanceCheckTest extends AbstractModuleTes
   }
 
   @Test
-  public void testValidateBetweenScopesOption() throws Exception {
+  void validateBetweenScopesOption() throws Exception {
     final String[] expected = {
       "42:9: " + getCheckMessage(MSG_KEY, "a", 2, 1),
       "50:9: " + getCheckMessage(MSG_KEY, "temp", 2, 1),
@@ -186,7 +186,7 @@ public class VariableDeclarationUsageDistanceCheckTest extends AbstractModuleTes
   }
 
   @Test
-  public void testIgnoreFinalOption() throws Exception {
+  void ignoreFinalOption() throws Exception {
     final String[] expected = {
       "42:9: " + getCheckMessage(MSG_KEY_EXT, "a", 2, 1),
       "50:9: " + getCheckMessage(MSG_KEY_EXT, "temp", 2, 1),
@@ -228,7 +228,7 @@ public class VariableDeclarationUsageDistanceCheckTest extends AbstractModuleTes
   }
 
   @Test
-  public void testTokensNotNull() {
+  void tokensNotNull() {
     final VariableDeclarationUsageDistanceCheck check = new VariableDeclarationUsageDistanceCheck();
     assertWithMessage("Acceptable tokens should not be null")
         .that(check.getAcceptableTokens())
@@ -242,7 +242,7 @@ public class VariableDeclarationUsageDistanceCheckTest extends AbstractModuleTes
   }
 
   @Test
-  public void testDefaultConfiguration() throws Exception {
+  void defaultConfiguration() throws Exception {
     final String[] expected = {
       "83:9: " + getCheckMessage(MSG_KEY_EXT, "count", 4, 3),
       "231:9: " + getCheckMessage(MSG_KEY_EXT, "t", 5, 3),
@@ -258,7 +258,7 @@ public class VariableDeclarationUsageDistanceCheckTest extends AbstractModuleTes
   }
 
   @Test
-  public void testDefaultConfiguration2() throws Exception {
+  void defaultConfiguration2() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -266,7 +266,7 @@ public class VariableDeclarationUsageDistanceCheckTest extends AbstractModuleTes
   }
 
   @Test
-  public void testAnonymousClass() throws Exception {
+  void anonymousClass() throws Exception {
     final String[] expected = {
       "19:9: " + getCheckMessage(MSG_KEY_EXT, "prefs", 4, 3),
     };
@@ -276,7 +276,7 @@ public class VariableDeclarationUsageDistanceCheckTest extends AbstractModuleTes
   }
 
   @Test
-  public void testLabels() throws Exception {
+  void labels() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -284,7 +284,7 @@ public class VariableDeclarationUsageDistanceCheckTest extends AbstractModuleTes
   }
 
   @Test
-  public void testVariableDeclarationUsageDistanceSwitchExpressions() throws Exception {
+  void variableDeclarationUsageDistanceSwitchExpressions() throws Exception {
 
     final int maxDistance = 1;
     final String[] expected = {
@@ -303,7 +303,7 @@ public class VariableDeclarationUsageDistanceCheckTest extends AbstractModuleTes
   }
 
   @Test
-  public void testVariableDeclarationUsageDistanceSwitchExpressions2() throws Exception {
+  void variableDeclarationUsageDistanceSwitchExpressions2() throws Exception {
     final int maxDistance = 1;
     final String[] expected = {
       "16:9: " + getCheckMessage(MSG_KEY, "i", 2, maxDistance),
@@ -314,7 +314,7 @@ public class VariableDeclarationUsageDistanceCheckTest extends AbstractModuleTes
   }
 
   @Test
-  public void testGeneralClass3() throws Exception {
+  void generalClass3() throws Exception {
     final String[] expected = {
       "46:9: " + getCheckMessage(MSG_KEY, "a", 2, 1),
     };
@@ -324,7 +324,7 @@ public class VariableDeclarationUsageDistanceCheckTest extends AbstractModuleTes
   }
 
   @Test
-  public void testGeneralClass4() throws Exception {
+  void generalClass4() throws Exception {
     final String[] expected = {
       "26:9: " + getCheckMessage(MSG_KEY, "z", 3, 1),
     };
@@ -334,7 +334,7 @@ public class VariableDeclarationUsageDistanceCheckTest extends AbstractModuleTes
   }
 
   @Test
-  public void testVariableDeclarationUsageDistanceTryResources() throws Exception {
+  void variableDeclarationUsageDistanceTryResources() throws Exception {
     final String[] expected = {
       "19:9: " + getCheckMessage(MSG_KEY, "a", 2, 1),
       "20:9: " + getCheckMessage(MSG_KEY, "b", 2, 1),
@@ -345,14 +345,14 @@ public class VariableDeclarationUsageDistanceCheckTest extends AbstractModuleTes
   }
 
   @Test
-  public void testVariableDeclarationUsageDistance4() throws Exception {
+  void variableDeclarationUsageDistance4() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputVariableDeclarationUsageDistance3.java"), expected);
   }
 
   @Test
-  public void testVariableDeclarationUsageDistanceScope2() throws Exception {
+  void variableDeclarationUsageDistanceScope2() throws Exception {
     final String[] expected = {
       "16:9: " + getCheckMessage(MSG_KEY, "i", 5, 1),
     };
@@ -362,7 +362,7 @@ public class VariableDeclarationUsageDistanceCheckTest extends AbstractModuleTes
   }
 
   @Test
-  public void testVariableDeclarationUsageDistance1() throws Exception {
+  void variableDeclarationUsageDistance1() throws Exception {
     final String[] expected = {
       "15:9: " + getCheckMessage(MSG_KEY, "i", 2, 1),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/design/DesignForExtensionCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/design/DesignForExtensionCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class DesignForExtensionCheckTest extends AbstractModuleTestSupport {
+final class DesignForExtensionCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class DesignForExtensionCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final DesignForExtensionCheck checkObj = new DesignForExtensionCheck();
     final int[] expected = {TokenTypes.METHOD_DEF};
     assertWithMessage("Default required tokens are invalid")
@@ -44,7 +44,7 @@ public class DesignForExtensionCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIt() throws Exception {
+  void it() throws Exception {
     final String[] expected = {
       "50:5: " + getCheckMessage(MSG_KEY, "InputDesignForExtension", "doh"),
       "104:9: " + getCheckMessage(MSG_KEY, "anotherNonFinalClass", "someMethod"),
@@ -53,7 +53,7 @@ public class DesignForExtensionCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final DesignForExtensionCheck obj = new DesignForExtensionCheck();
     final int[] expected = {TokenTypes.METHOD_DEF};
     assertWithMessage("Default acceptable tokens are invalid")
@@ -62,7 +62,7 @@ public class DesignForExtensionCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOverridableMethods() throws Exception {
+  void overridableMethods() throws Exception {
     final String[] expected = {
       "14:9: " + getCheckMessage(MSG_KEY, "A", "foo1"),
       "38:9: " + getCheckMessage(MSG_KEY, "A", "foo8"),
@@ -89,7 +89,7 @@ public class DesignForExtensionCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoredAnnotationsOption() throws Exception {
+  void ignoredAnnotationsOption() throws Exception {
     final String[] expected = {
       "39:5: " + getCheckMessage(MSG_KEY, "InputDesignForExtensionIgnoredAnnotations", "foo1"),
       "149:5: " + getCheckMessage(MSG_KEY, "InputDesignForExtensionIgnoredAnnotations", "foo21"),
@@ -102,14 +102,14 @@ public class DesignForExtensionCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreAnnotationsOptionWithMultipleAnnotations() throws Exception {
+  void ignoreAnnotationsOptionWithMultipleAnnotations() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputDesignForExtensionMultipleAnnotations.java"), expected);
   }
 
   @Test
-  public void testNativeMethods() throws Exception {
+  void nativeMethods() throws Exception {
     final String[] expected = {
       "16:5: " + getCheckMessage(MSG_KEY, "InputDesignForExtensionNativeMethods", "foo1"),
       "32:5: " + getCheckMessage(MSG_KEY, "InputDesignForExtensionNativeMethods", "foo6"),
@@ -118,7 +118,7 @@ public class DesignForExtensionCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDesignForExtensionRecords() throws Exception {
+  void designForExtensionRecords() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -127,7 +127,7 @@ public class DesignForExtensionCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRequiredJavadocPhrase() throws Exception {
+  void requiredJavadocPhrase() throws Exception {
     final String className = "InputDesignForExtensionRequiredJavadocPhrase";
     final String[] expected = {
       "41:5: " + getCheckMessage(MSG_KEY, className, "foo5"),
@@ -140,7 +140,7 @@ public class DesignForExtensionCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRequiredJavadocPhraseMultiLine() throws Exception {
+  void requiredJavadocPhraseMultiLine() throws Exception {
     final String className = "InputDesignForExtensionRequiredJavadocPhraseMultiLine";
     final String[] expected = {
       "23:5: " + getCheckMessage(MSG_KEY, className, "foo2"),
@@ -150,7 +150,7 @@ public class DesignForExtensionCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInterfaceMemberScopeIsPublic() throws Exception {
+  void interfaceMemberScopeIsPublic() throws Exception {
     final String[] expected = {
       "15:9: " + getCheckMessage(MSG_KEY, "Inner", "getProperty"),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/design/FinalClassCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/design/FinalClassCheckTest.java
@@ -32,7 +32,7 @@ import java.io.File;
 import java.util.Optional;
 import org.junit.jupiter.api.Test;
 
-public class FinalClassCheckTest extends AbstractModuleTestSupport {
+final class FinalClassCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -40,7 +40,7 @@ public class FinalClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final FinalClassCheck checkObj = new FinalClassCheck();
     final int[] expected = {
       TokenTypes.ANNOTATION_DEF,
@@ -58,7 +58,7 @@ public class FinalClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFinalClass() throws Exception {
+  void finalClass() throws Exception {
     final String[] expected = {
       "11:1: " + getCheckMessage(MSG_KEY, "InputFinalClass"),
       "19:4: " + getCheckMessage(MSG_KEY, "test4"),
@@ -72,7 +72,7 @@ public class FinalClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClassWithPrivateCtorAndNestedExtendingSubclass() throws Exception {
+  void classWithPrivateCtorAndNestedExtendingSubclass() throws Exception {
     final String[] expected = {
       "13:9: " + getCheckMessage(MSG_KEY, "ExtendA"),
       "18:9: " + getCheckMessage(MSG_KEY, "ExtendB"),
@@ -85,7 +85,7 @@ public class FinalClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClassWithPrivateCtorAndNestedExtendingSubclassWithoutPackage() throws Exception {
+  void classWithPrivateCtorAndNestedExtendingSubclassWithoutPackage() throws Exception {
     final String[] expected = {
       "11:9: " + getCheckMessage(MSG_KEY, "ExtendA"),
       "14:5: " + getCheckMessage(MSG_KEY, "C"),
@@ -98,7 +98,7 @@ public class FinalClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFinalClassConstructorInRecord() throws Exception {
+  void finalClassConstructorInRecord() throws Exception {
 
     final String[] expected = {
       "27:9: " + getCheckMessage(MSG_KEY, "F"),
@@ -109,7 +109,7 @@ public class FinalClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testImproperToken() {
+  void improperToken() {
     final FinalClassCheck finalClassCheck = new FinalClassCheck();
     final DetailAstImpl badAst = new DetailAstImpl();
     final int unsupportedTokenByCheck = TokenTypes.COMPILATION_UNIT;
@@ -125,7 +125,7 @@ public class FinalClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final FinalClassCheck obj = new FinalClassCheck();
     final int[] expected = {
       TokenTypes.ANNOTATION_DEF,
@@ -143,7 +143,7 @@ public class FinalClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFinalClassInnerAndNestedClasses() throws Exception {
+  void finalClassInnerAndNestedClasses() throws Exception {
     final String[] expected = {
       "16:5: " + getCheckMessage(MSG_KEY, "SubClass"),
       "19:5: " + getCheckMessage(MSG_KEY, "SameName"),
@@ -155,7 +155,7 @@ public class FinalClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFinalClassStaticNestedClasses() throws Exception {
+  void finalClassStaticNestedClasses() throws Exception {
 
     final String[] expected = {
       "14:17: " + getCheckMessage(MSG_KEY, "C"),
@@ -171,7 +171,7 @@ public class FinalClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFinalClassEnum() throws Exception {
+  void finalClassEnum() throws Exception {
     final String[] expected = {
       "35:5: " + getCheckMessage(MSG_KEY, "DerivedClass"),
     };
@@ -179,7 +179,7 @@ public class FinalClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFinalClassAnnotation() throws Exception {
+  void finalClassAnnotation() throws Exception {
     final String[] expected = {
       "15:5: " + getCheckMessage(MSG_KEY, "DerivedClass"),
     };
@@ -187,7 +187,7 @@ public class FinalClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFinalClassInterface() throws Exception {
+  void finalClassInterface() throws Exception {
     final String[] expected = {
       "15:5: " + getCheckMessage(MSG_KEY, "DerivedClass"),
     };
@@ -195,7 +195,7 @@ public class FinalClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFinalClassAnonymousInnerClass() throws Exception {
+  void finalClassAnonymousInnerClass() throws Exception {
     final String[] expected = {
       "11:9: " + getCheckMessage(MSG_KEY, "b"),
       "27:9: " + getCheckMessage(MSG_KEY, "m"),
@@ -210,7 +210,7 @@ public class FinalClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFinalClassNestedInInterface() throws Exception {
+  void finalClassNestedInInterface() throws Exception {
     final String[] expected = {
       "24:5: " + getCheckMessage(MSG_KEY, "b"),
       "28:13: " + getCheckMessage(MSG_KEY, "m"),
@@ -221,7 +221,7 @@ public class FinalClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFinalClassNestedInEnum() throws Exception {
+  void finalClassNestedInEnum() throws Exception {
     final String[] expected = {
       "13:9: " + getCheckMessage(MSG_KEY, "j"), "27:9: " + getCheckMessage(MSG_KEY, "n"),
     };
@@ -230,7 +230,7 @@ public class FinalClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFinalClassNestedInRecord() throws Exception {
+  void finalClassNestedInRecord() throws Exception {
     final String[] expected = {
       "13:9: " + getCheckMessage(MSG_KEY, "c"),
       "31:13: " + getCheckMessage(MSG_KEY, "j"),
@@ -247,7 +247,7 @@ public class FinalClassCheckTest extends AbstractModuleTestSupport {
    * @throws Exception when code tested throws exception
    */
   @Test
-  public void testClearState() throws Exception {
+  void clearState() throws Exception {
     final FinalClassCheck check = new FinalClassCheck();
     final DetailAST root =
         JavaParser.parseFile(
@@ -260,14 +260,14 @@ public class FinalClassCheckTest extends AbstractModuleTestSupport {
         .that(
             TestUtil.isStatefulFieldClearedDuringBeginTree(
                 check,
-                packageDef.get(),
+                packageDef.orElseThrow(),
                 "packageName",
                 packageName -> ((String) packageName).isEmpty()))
         .isTrue();
   }
 
   @Test
-  public void testPrivateClassWithDefaultCtor() throws Exception {
+  void privateClassWithDefaultCtor() throws Exception {
     final String[] expected = {
       "14:5: " + getCheckMessage(MSG_KEY, "Some2"),
       "19:1: " + getCheckMessage(MSG_KEY, "Some"),
@@ -286,7 +286,7 @@ public class FinalClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPrivateClassWithDefaultCtor2() throws Exception {
+  void privateClassWithDefaultCtor2() throws Exception {
     final String[] expected = {
       "22:5: " + getCheckMessage(MSG_KEY, "PrivateClass"),
       "34:5: " + getCheckMessage(MSG_KEY, "Check"),
@@ -297,7 +297,7 @@ public class FinalClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPrivateClassWithDefaultCtor3() throws Exception {
+  void privateClassWithDefaultCtor3() throws Exception {
     final String[] expected = {
       "26:5: " + getCheckMessage(MSG_KEY, "MyClass"),
       "30:5: " + getCheckMessage(MSG_KEY, "Check2"),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/design/HideUtilityClassConstructorCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/design/HideUtilityClassConstructorCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class HideUtilityClassConstructorCheckTest extends AbstractModuleTestSupport {
+final class HideUtilityClassConstructorCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class HideUtilityClassConstructorCheckTest extends AbstractModuleTestSupp
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final HideUtilityClassConstructorCheck checkObj = new HideUtilityClassConstructorCheck();
     final int[] expected = {TokenTypes.CLASS_DEF};
     assertWithMessage("Default required tokens are invalid")
@@ -44,7 +44,7 @@ public class HideUtilityClassConstructorCheckTest extends AbstractModuleTestSupp
   }
 
   @Test
-  public void testUtilClass() throws Exception {
+  void utilClass() throws Exception {
     final String[] expected = {
       "9:1: " + getCheckMessage(MSG_KEY),
     };
@@ -53,7 +53,7 @@ public class HideUtilityClassConstructorCheckTest extends AbstractModuleTestSupp
   }
 
   @Test
-  public void testUtilClassPublicCtor() throws Exception {
+  void utilClassPublicCtor() throws Exception {
     final String[] expected = {
       "9:1: " + getCheckMessage(MSG_KEY),
     };
@@ -61,69 +61,69 @@ public class HideUtilityClassConstructorCheckTest extends AbstractModuleTestSupp
   }
 
   @Test
-  public void testUtilClassPrivateCtor() throws Exception {
+  void utilClassPrivateCtor() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputHideUtilityClassConstructorPrivate.java"), expected);
   }
 
   /** Non-static methods - always OK. */
   @Test
-  public void testNonUtilClass() throws Exception {
+  void nonUtilClass() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputHideUtilityClassConstructorDesignForExtension.java"), expected);
   }
 
   @Test
-  public void testDerivedNonUtilClass() throws Exception {
+  void derivedNonUtilClass() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputHideUtilityClassConstructorNonUtilityClass.java"), expected);
   }
 
   @Test
-  public void testOnlyNonStaticFieldNonUtilClass() throws Exception {
+  void onlyNonStaticFieldNonUtilClass() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputHideUtilityClassConstructorRegression.java"), expected);
   }
 
   @Test
-  public void testEmptyAbstractClass() throws Exception {
+  void emptyAbstractClass() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputHideUtilityClassConstructorAbstractSerializable.java"), expected);
   }
 
   @Test
-  public void testEmptyAbstractClass2() throws Exception {
+  void emptyAbstractClass2() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputHideUtilityClassConstructorAbstract.java"), expected);
   }
 
   @Test
-  public void testEmptyClassWithOnlyPrivateFields() throws Exception {
+  void emptyClassWithOnlyPrivateFields() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputHideUtilityClassConstructorSerializable.java"), expected);
   }
 
   @Test
-  public void testClassWithStaticInnerClass() throws Exception {
+  void classWithStaticInnerClass() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputHideUtilityClassConstructorSerializableInnerStatic.java"), expected);
   }
 
   @Test
-  public void testProtectedCtor() throws Exception {
+  void protectedCtor() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputHideUtilityClassConstructor.java"), expected);
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final HideUtilityClassConstructorCheck obj = new HideUtilityClassConstructorCheck();
     final int[] expected = {TokenTypes.CLASS_DEF};
     assertWithMessage("Default acceptable tokens are invalid")
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/design/InnerTypeLastCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/design/InnerTypeLastCheckTest.java
@@ -29,7 +29,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.io.File;
 import org.junit.jupiter.api.Test;
 
-public class InnerTypeLastCheckTest extends AbstractModuleTestSupport {
+final class InnerTypeLastCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -37,7 +37,7 @@ public class InnerTypeLastCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final InnerTypeLastCheck checkObj = new InnerTypeLastCheck();
     final int[] expected = {
       TokenTypes.CLASS_DEF, TokenTypes.INTERFACE_DEF, TokenTypes.RECORD_DEF,
@@ -48,7 +48,7 @@ public class InnerTypeLastCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMembersBeforeInner() throws Exception {
+  void membersBeforeInner() throws Exception {
     final String[] expected = {
       "50:9: " + getCheckMessage(MSG_KEY),
       "71:9: " + getCheckMessage(MSG_KEY),
@@ -60,19 +60,19 @@ public class InnerTypeLastCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIfRootClassChecked() throws Exception {
+  void ifRootClassChecked() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputInnerTypeLastClassRootClass.java"), expected);
   }
 
   @Test
-  public void testIfRootClassChecked2() throws Exception {
+  void ifRootClassChecked2() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputInnerTypeLastClassRootClass2.java"), expected);
   }
 
   @Test
-  public void testIfRootClassChecked3() throws Exception {
+  void ifRootClassChecked3() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(InnerTypeLastCheck.class);
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verify(
@@ -86,7 +86,7 @@ public class InnerTypeLastCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInnerTypeBeforeCtor() throws Exception {
+  void innerTypeBeforeCtor() throws Exception {
     final String[] expected = {
       "13:5: " + getCheckMessage(MSG_KEY),
       "22:5: " + getCheckMessage(MSG_KEY),
@@ -96,7 +96,7 @@ public class InnerTypeLastCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInnerTypeLastRecords() throws Exception {
+  void innerTypeLastRecords() throws Exception {
 
     final String[] expected = {
       "17:9: " + getCheckMessage(MSG_KEY),
@@ -111,7 +111,7 @@ public class InnerTypeLastCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInnerTypeLastCstyleArray() throws Exception {
+  void innerTypeLastCstyleArray() throws Exception {
     final String[] expected = {
       "11:5: " + getCheckMessage(MSG_KEY),
       "12:5: " + getCheckMessage(MSG_KEY),
@@ -122,7 +122,7 @@ public class InnerTypeLastCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final InnerTypeLastCheck obj = new InnerTypeLastCheck();
     final int[] expected = {
       TokenTypes.CLASS_DEF, TokenTypes.INTERFACE_DEF, TokenTypes.RECORD_DEF,
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/design/InterfaceIsTypeCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/design/InterfaceIsTypeCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class InterfaceIsTypeCheckTest extends AbstractModuleTestSupport {
+final class InterfaceIsTypeCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class InterfaceIsTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "28:5: " + getCheckMessage(MSG_KEY),
     };
@@ -42,7 +42,7 @@ public class InterfaceIsTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowMarker() throws Exception {
+  void allowMarker() throws Exception {
     final String[] expected = {
       "23:5: " + getCheckMessage(MSG_KEY), "28:5: " + getCheckMessage(MSG_KEY),
     };
@@ -50,7 +50,7 @@ public class InterfaceIsTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final InterfaceIsTypeCheck obj = new InterfaceIsTypeCheck();
     final int[] expected = {TokenTypes.INTERFACE_DEF};
     assertWithMessage("Default acceptable tokens are invalid")
@@ -59,7 +59,7 @@ public class InterfaceIsTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final InterfaceIsTypeCheck obj = new InterfaceIsTypeCheck();
     final int[] expected = {TokenTypes.INTERFACE_DEF};
     assertWithMessage("Default required tokens are invalid")
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/design/MutableExceptionCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/design/MutableExceptionCheckTest.java
@@ -34,7 +34,7 @@ import java.util.List;
 import org.antlr.v4.runtime.CommonToken;
 import org.junit.jupiter.api.Test;
 
-public class MutableExceptionCheckTest extends AbstractModuleTestSupport {
+final class MutableExceptionCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -42,7 +42,7 @@ public class MutableExceptionCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClassExtendsGenericClass() throws Exception {
+  void classExtendsGenericClass() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -51,7 +51,7 @@ public class MutableExceptionCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
 
     final String[] expected = {
       "14:9: " + getCheckMessage(MSG_KEY, "errorCode"),
@@ -63,7 +63,7 @@ public class MutableExceptionCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMultipleInputs() throws Exception {
+  void multipleInputs() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(MutableExceptionCheck.class);
     final String filePath1 = getPath("InputMutableException2.java");
     final String filePath2 = getPath("InputMutableExceptionMultipleInputs.java");
@@ -87,7 +87,7 @@ public class MutableExceptionCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFormat() throws Exception {
+  void format() throws Exception {
     final String[] expected = {
       "42:13: " + getCheckMessage(MSG_KEY, "errorCode"),
     };
@@ -96,7 +96,7 @@ public class MutableExceptionCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNested() throws Exception {
+  void nested() throws Exception {
 
     final String[] expected = {
       "15:9: " + getCheckMessage(MSG_KEY, "code"),
@@ -106,7 +106,7 @@ public class MutableExceptionCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final MutableExceptionCheck obj = new MutableExceptionCheck();
     final int[] expected = {TokenTypes.CLASS_DEF, TokenTypes.VARIABLE_DEF};
     assertWithMessage("Default acceptable tokens are invalid")
@@ -115,7 +115,7 @@ public class MutableExceptionCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final MutableExceptionCheck obj = new MutableExceptionCheck();
     final int[] expected = {TokenTypes.CLASS_DEF, TokenTypes.VARIABLE_DEF};
     assertWithMessage("Default required tokens are invalid")
@@ -124,7 +124,7 @@ public class MutableExceptionCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWrongTokenType() {
+  void wrongTokenType() {
     final MutableExceptionCheck obj = new MutableExceptionCheck();
     final DetailAstImpl ast = new DetailAstImpl();
     ast.initialize(new CommonToken(TokenTypes.INTERFACE_DEF, "interface"));
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/design/OneTopLevelClassCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/design/OneTopLevelClassCheckTest.java
@@ -32,7 +32,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class OneTopLevelClassCheckTest extends AbstractModuleTestSupport {
+final class OneTopLevelClassCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -40,7 +40,7 @@ public class OneTopLevelClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final OneTopLevelClassCheck checkObj = new OneTopLevelClassCheck();
     final int[] expected = {TokenTypes.COMPILATION_UNIT};
     assertWithMessage("Required tokens are invalid.")
@@ -49,7 +49,7 @@ public class OneTopLevelClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClearState() throws Exception {
+  void clearState() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(OneTopLevelClassCheck.class);
     final String firstInputFilePath = getPath("InputOneTopLevelClassDeclarationOrder.java");
     final String secondInputFilePath = getPath("InputOneTopLevelClassInterface2.java");
@@ -75,7 +75,7 @@ public class OneTopLevelClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAcceptableTokens() {
+  void acceptableTokens() {
     final OneTopLevelClassCheck check = new OneTopLevelClassCheck();
     final int[] expected = {TokenTypes.COMPILATION_UNIT};
     assertWithMessage("Default required tokens are invalid")
@@ -84,31 +84,31 @@ public class OneTopLevelClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFileWithOneTopLevelClass() throws Exception {
+  void fileWithOneTopLevelClass() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputOneTopLevelClass.java"), expected);
   }
 
   @Test
-  public void testFileWithOneTopLevelInterface() throws Exception {
+  void fileWithOneTopLevelInterface() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputOneTopLevelClassInterface.java"), expected);
   }
 
   @Test
-  public void testFileWithOneTopLevelEnum() throws Exception {
+  void fileWithOneTopLevelEnum() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputOneTopLevelClassEnum.java"), expected);
   }
 
   @Test
-  public void testFileWithOneTopLevelAnnotation() throws Exception {
+  void fileWithOneTopLevelAnnotation() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputOneTopLevelClassAnnotation.java"), expected);
   }
 
   @Test
-  public void testFileWithNoPublicTopLevelClass() throws Exception {
+  void fileWithNoPublicTopLevelClass() throws Exception {
     final String[] expected = {
       "14:1: " + getCheckMessage(MSG_KEY, "InputOneTopLevelClassNoPublic2"),
     };
@@ -116,7 +116,7 @@ public class OneTopLevelClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFileWithThreeTopLevelInterface() throws Exception {
+  void fileWithThreeTopLevelInterface() throws Exception {
     final String[] expected = {
       "9:1: " + getCheckMessage(MSG_KEY, "InputOneTopLevelClassInterface3inner1"),
       "17:1: " + getCheckMessage(MSG_KEY, "InputOneTopLevelClassInterface3inner2"),
@@ -125,7 +125,7 @@ public class OneTopLevelClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFileWithThreeTopLevelEnum() throws Exception {
+  void fileWithThreeTopLevelEnum() throws Exception {
     final String[] expected = {
       "9:1: " + getCheckMessage(MSG_KEY, "InputOneTopLevelClassEnum2inner1"),
       "17:1: " + getCheckMessage(MSG_KEY, "InputOneTopLevelClassEnum2inner2"),
@@ -134,7 +134,7 @@ public class OneTopLevelClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFileWithThreeTopLevelAnnotation() throws Exception {
+  void fileWithThreeTopLevelAnnotation() throws Exception {
     final String[] expected = {
       "15:1: " + getCheckMessage(MSG_KEY, "InputOneTopLevelClassAnnotation2A"),
       "20:1: " + getCheckMessage(MSG_KEY, "InputOneTopLevelClassAnnotation2B"),
@@ -143,7 +143,7 @@ public class OneTopLevelClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFileWithFewTopLevelClasses() throws Exception {
+  void fileWithFewTopLevelClasses() throws Exception {
     final String[] expected = {
       "31:1: " + getCheckMessage(MSG_KEY, "NoSuperClone"),
       "35:1: " + getCheckMessage(MSG_KEY, "InnerClone"),
@@ -157,7 +157,7 @@ public class OneTopLevelClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFileWithSecondEnumTopLevelClass() throws Exception {
+  void fileWithSecondEnumTopLevelClass() throws Exception {
     final String[] expected = {
       "16:1: " + getCheckMessage(MSG_KEY, "InputDeclarationOrderEnum2"),
       "26:1: " + getCheckMessage(MSG_KEY, "InputDeclarationOrderAnnotation2"),
@@ -166,13 +166,13 @@ public class OneTopLevelClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackageInfoWithNoTypesDeclared() throws Exception {
+  void packageInfoWithNoTypesDeclared() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getNonCompilablePath("package-info.java"), expected);
   }
 
   @Test
-  public void testFileWithMultipleSameLine() throws Exception {
+  void fileWithMultipleSameLine() throws Exception {
     final String[] expected = {
       "9:47: " + getCheckMessage(MSG_KEY, "ViolatingSecondType"),
     };
@@ -180,7 +180,7 @@ public class OneTopLevelClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFileWithIndentation() throws Exception {
+  void fileWithIndentation() throws Exception {
     final String[] expected = {
       "13:2: " + getCheckMessage(MSG_KEY, "ViolatingIndentedClass1"),
       "17:5: " + getCheckMessage(MSG_KEY, "ViolatingIndentedClass2"),
@@ -190,7 +190,7 @@ public class OneTopLevelClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOneTopLevelClassRecords() throws Exception {
+  void oneTopLevelClassRecords() throws Exception {
     final String[] expected = {
       "13:1: " + getCheckMessage(MSG_KEY, "TestRecord1"),
       "17:1: " + getCheckMessage(MSG_KEY, "TestRecord2"),
@@ -200,7 +200,7 @@ public class OneTopLevelClassCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOneTopLevelClassEmpty() throws Exception {
+  void oneTopLevelClassEmpty() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getNonCompilablePath("InputOneTopLevelClassEmpty.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/design/ThrowsCountCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/design/ThrowsCountCheckTest.java
@@ -28,7 +28,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.antlr.v4.runtime.CommonToken;
 import org.junit.jupiter.api.Test;
 
-public class ThrowsCountCheckTest extends AbstractModuleTestSupport {
+final class ThrowsCountCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -36,7 +36,7 @@ public class ThrowsCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
 
     final String[] expected = {
       "25:20: " + getCheckMessage(MSG_KEY, 5, 4),
@@ -49,7 +49,7 @@ public class ThrowsCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMax() throws Exception {
+  void max() throws Exception {
 
     final String[] expected = {
       "35:20: " + getCheckMessage(MSG_KEY, 6, 5),
@@ -59,7 +59,7 @@ public class ThrowsCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final ThrowsCountCheck obj = new ThrowsCountCheck();
     final int[] expected = {TokenTypes.LITERAL_THROWS};
     assertWithMessage("Default acceptable tokens are invalid")
@@ -68,7 +68,7 @@ public class ThrowsCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final ThrowsCountCheck obj = new ThrowsCountCheck();
     final int[] expected = {TokenTypes.LITERAL_THROWS};
     assertWithMessage("Default required tokens are invalid")
@@ -77,7 +77,7 @@ public class ThrowsCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWrongTokenType() {
+  void wrongTokenType() {
     final ThrowsCountCheck obj = new ThrowsCountCheck();
     final DetailAstImpl ast = new DetailAstImpl();
     ast.initialize(new CommonToken(TokenTypes.CLASS_DEF, "class"));
@@ -92,7 +92,7 @@ public class ThrowsCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNotIgnorePrivateMethod() throws Exception {
+  void notIgnorePrivateMethod() throws Exception {
     final String[] expected = {
       "25:20: " + getCheckMessage(MSG_KEY, 5, 4),
       "30:20: " + getCheckMessage(MSG_KEY, 5, 4),
@@ -104,7 +104,7 @@ public class ThrowsCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMethodWithAnnotation() throws Exception {
+  void methodWithAnnotation() throws Exception {
     final String[] expected = {
       "26:26: " + getCheckMessage(MSG_KEY, 5, 4),
     };
@@ -112,7 +112,7 @@ public class ThrowsCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOverriding() throws Exception {
+  void overriding() throws Exception {
     final String[] expected = {
       "17:20: " + getCheckMessage(MSG_KEY, 1, 0),
       "21:20: " + getCheckMessage(MSG_KEY, 1, 0),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/design/VisibilityModifierCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/design/VisibilityModifierCheckTest.java
@@ -33,7 +33,7 @@ import java.io.File;
 import org.antlr.v4.runtime.CommonToken;
 import org.junit.jupiter.api.Test;
 
-public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
+final class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -41,7 +41,7 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final VisibilityModifierCheck checkObj = new VisibilityModifierCheck();
     final int[] expected = {
       TokenTypes.VARIABLE_DEF, TokenTypes.IMPORT,
@@ -52,7 +52,7 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInner() throws Exception {
+  void inner() throws Exception {
     final String[] expected = {
       "47:24: " + getCheckMessage(MSG_KEY, "rData"),
       "50:27: " + getCheckMessage(MSG_KEY, "protectedVariable"),
@@ -66,7 +66,7 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreAccess() throws Exception {
+  void ignoreAccess() throws Exception {
     final String[] expected = {
       "34:20: " + getCheckMessage(MSG_KEY, "fData"),
       "94:20: " + getCheckMessage(MSG_KEY, "someValue"),
@@ -75,7 +75,7 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSimple() throws Exception {
+  void simple() throws Exception {
     final String[] expected = {
       "49:19: " + getCheckMessage(MSG_KEY, "mNumCreated2"),
       "59:23: " + getCheckMessage(MSG_KEY, "sTest1"),
@@ -88,7 +88,7 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStrictJavadoc() throws Exception {
+  void strictJavadoc() throws Exception {
     final String[] expected = {
       "49:9: " + getCheckMessage(MSG_KEY, "mLen"),
       "50:19: " + getCheckMessage(MSG_KEY, "mDeer"),
@@ -98,7 +98,7 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowPublicFinalFieldsInImmutableClass() throws Exception {
+  void allowPublicFinalFieldsInImmutableClass() throws Exception {
     final String[] expected = {
       "33:39: " + getCheckMessage(MSG_KEY, "includes"),
       "34:39: " + getCheckMessage(MSG_KEY, "excludes"),
@@ -112,7 +112,7 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowPublicFinalFieldsInImmutableClassWithNonCanonicalClasses() throws Exception {
+  void allowPublicFinalFieldsInImmutableClassWithNonCanonicalClasses() throws Exception {
     final String[] expected = {
       "28:39: " + getCheckMessage(MSG_KEY, "includes"),
       "29:39: " + getCheckMessage(MSG_KEY, "excludes"),
@@ -130,7 +130,7 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDisAllowPublicFinalAndImmutableFieldsInImmutableClass() throws Exception {
+  void disAllowPublicFinalAndImmutableFieldsInImmutableClass() throws Exception {
     final String[] expected = {
       "32:22: " + getCheckMessage(MSG_KEY, "someIntValue"),
       "33:39: " + getCheckMessage(MSG_KEY, "includes"),
@@ -152,7 +152,7 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowPublicFinalFieldsInNonFinalClass() throws Exception {
+  void allowPublicFinalFieldsInNonFinalClass() throws Exception {
     final String[] expected = {
       "55:20: " + getCheckMessage(MSG_KEY, "value"),
       "57:24: " + getCheckMessage(MSG_KEY, "bValue"),
@@ -162,7 +162,7 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUserSpecifiedImmutableClassesList() throws Exception {
+  void userSpecifiedImmutableClassesList() throws Exception {
     final String[] expected = {
       "30:29: " + getCheckMessage(MSG_KEY, "money"),
       "47:35: " + getCheckMessage(MSG_KEY, "uri"),
@@ -177,7 +177,7 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testImmutableSpecifiedSameTypeName() throws Exception {
+  void immutableSpecifiedSameTypeName() throws Exception {
     final String[] expected = {
       "23:46: " + getCheckMessage(MSG_KEY, "calendar"),
       "26:36: " + getCheckMessage(MSG_KEY, "address"),
@@ -188,7 +188,7 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testImmutableValueSameTypeName() throws Exception {
+  void immutableValueSameTypeName() throws Exception {
     final String[] expected = {
       "28:46: " + getCheckMessage(MSG_KEY, "calendar"),
       "29:59: " + getCheckMessage(MSG_KEY, "calendar2"),
@@ -199,21 +199,21 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testImmutableStarImportFalseNegative() throws Exception {
+  void immutableStarImportFalseNegative() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputVisibilityModifierImmutableStarImport.java"), expected);
   }
 
   @Test
-  public void testImmutableStarImportNoWarn() throws Exception {
+  void immutableStarImportNoWarn() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputVisibilityModifierImmutableStarImport2.java"), expected);
   }
 
   @Test
-  public void testDefaultAnnotationPatterns() throws Exception {
+  void defaultAnnotationPatterns() throws Exception {
     final String[] expected = {
       "61:19: " + getCheckMessage(MSG_KEY, "customAnnotatedPublic"),
       "64:12: " + getCheckMessage(MSG_KEY, "customAnnotatedPackage"),
@@ -226,7 +226,7 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCustomAnnotationPatterns() throws Exception {
+  void customAnnotationPatterns() throws Exception {
     final String[] expected = {
       "37:28: " + getCheckMessage(MSG_KEY, "publicJUnitRule"),
       "40:28: " + getCheckMessage(MSG_KEY, "fqPublicJUnitRule"),
@@ -246,7 +246,7 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreAnnotationNoPattern() throws Exception {
+  void ignoreAnnotationNoPattern() throws Exception {
     final String[] expected = {
       "36:28: " + getCheckMessage(MSG_KEY, "publicJUnitRule"),
       "39:28: " + getCheckMessage(MSG_KEY, "fqPublicJUnitRule"),
@@ -269,7 +269,7 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreAnnotationSameName() throws Exception {
+  void ignoreAnnotationSameName() throws Exception {
     final String[] expected = {
       "33:28: " + getCheckMessage(MSG_KEY, "publicJUnitRule"),
       "36:28: " + getCheckMessage(MSG_KEY, "publicJUnitClassRule"),
@@ -279,7 +279,7 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final VisibilityModifierCheck obj = new VisibilityModifierCheck();
     final int[] expected = {
       TokenTypes.VARIABLE_DEF, TokenTypes.IMPORT,
@@ -290,7 +290,7 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPublicImmutableFieldsNotAllowed() throws Exception {
+  void publicImmutableFieldsNotAllowed() throws Exception {
     final String[] expected = {
       "31:22: " + getCheckMessage(MSG_KEY, "someIntValue"),
       "32:39: " + getCheckMessage(MSG_KEY, "includes"),
@@ -302,7 +302,7 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPublicFinalFieldsNotAllowed() throws Exception {
+  void publicFinalFieldsNotAllowed() throws Exception {
     final String[] expected = {
       "31:22: " + getCheckMessage(MSG_KEY, "someIntValue"),
       "32:39: " + getCheckMessage(MSG_KEY, "includes"),
@@ -315,14 +315,14 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPublicFinalFieldsAllowed() throws Exception {
+  void publicFinalFieldsAllowed() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputVisibilityModifiersPublicImmutable3.java"), expected);
   }
 
   @Test
-  public void testPublicFinalFieldInEnum() throws Exception {
+  void publicFinalFieldInEnum() throws Exception {
     final String[] expected = {
       "35:23: " + getCheckMessage(MSG_KEY, "hole"),
     };
@@ -330,7 +330,7 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWrongTokenType() {
+  void wrongTokenType() {
     final VisibilityModifierCheck obj = new VisibilityModifierCheck();
     final DetailAstImpl ast = new DetailAstImpl();
     ast.initialize(new CommonToken(TokenTypes.CLASS_DEF, "class"));
@@ -345,7 +345,7 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNullModifiers() throws Exception {
+  void nullModifiers() throws Exception {
     final String[] expected = {
       "32:50: " + getCheckMessage(MSG_KEY, "i"),
     };
@@ -353,7 +353,7 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testVisibilityModifiersOfGenericFields() throws Exception {
+  void visibilityModifiersOfGenericFields() throws Exception {
     final String[] expected = {
       "31:56: " + getCheckMessage(MSG_KEY, "perfSeries"),
       "32:66: " + getCheckMessage(MSG_KEY, "peopleMap"),
@@ -388,7 +388,7 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
    * @throws Exception when exception occurred during execution.
    */
   @Test
-  public void testIsStarImportNullAst() throws Exception {
+  void isStarImportNullAst() throws Exception {
     final DetailAST importAst =
         JavaParser.parseFile(
                 new File(getPath("InputVisibilityModifierIsStarImport.java")),
@@ -402,7 +402,7 @@ public class VisibilityModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackageClassName() throws Exception {
+  void packageClassName() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getNonCompilablePath("InputVisibilityModifierPackageClassName.java"), expected);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/header/HeaderCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/header/HeaderCheckTest.java
@@ -40,7 +40,7 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
 import org.mockito.MockedConstruction;
 
-public class HeaderCheckTest extends AbstractModuleTestSupport {
+final class HeaderCheckTest extends AbstractModuleTestSupport {
 
   @TempDir public File temporaryFolder;
 
@@ -50,7 +50,7 @@ public class HeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticHeader() throws Exception {
+  void staticHeader() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(HeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputHeaderjava.header"));
     checkConfig.addProperty("ignoreLines", "");
@@ -61,7 +61,7 @@ public class HeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoHeader() throws Exception {
+  void noHeader() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(HeaderCheck.class);
 
     createChecker(checkConfig);
@@ -70,7 +70,7 @@ public class HeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWhitespaceHeader() throws Exception {
+  void whitespaceHeader() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(HeaderCheck.class);
     checkConfig.addProperty("header", "\n    \n");
 
@@ -80,7 +80,7 @@ public class HeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonExistentHeaderFile() throws Exception {
+  void nonExistentHeaderFile() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(HeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("nonExistent.file"));
     final CheckstyleException ex =
@@ -106,7 +106,7 @@ public class HeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidCharset() throws Exception {
+  void invalidCharset() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(HeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputHeaderjava.header"));
     checkConfig.addProperty("charset", "XSO-8859-1");
@@ -133,7 +133,7 @@ public class HeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyFilename() {
+  void emptyFilename() {
     final DefaultConfiguration checkConfig = createModuleConfig(HeaderCheck.class);
     checkConfig.addProperty("headerFile", "");
     final CheckstyleException ex =
@@ -161,7 +161,7 @@ public class HeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNullFilename() {
+  void nullFilename() {
     final DefaultConfiguration checkConfig = createModuleConfig(HeaderCheck.class);
     checkConfig.addProperty("headerFile", null);
     final CheckstyleException ex =
@@ -180,7 +180,7 @@ public class HeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNotMatch() throws Exception {
+  void notMatch() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(HeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputHeaderjava.header"));
     checkConfig.addProperty("ignoreLines", "");
@@ -195,7 +195,7 @@ public class HeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnore() throws Exception {
+  void ignore() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(HeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputHeaderjava.header"));
     checkConfig.addProperty("ignoreLines", "2");
@@ -204,7 +204,7 @@ public class HeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSetHeaderTwice() {
+  void setHeaderTwice() {
     final HeaderCheck check = new HeaderCheck();
     check.setHeader("Header");
     final IllegalArgumentException ex =
@@ -220,7 +220,7 @@ public class HeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIoExceptionWhenLoadingHeaderFile() throws Exception {
+  void ioExceptionWhenLoadingHeaderFile() throws Exception {
     final HeaderCheck check = new HeaderCheck();
     check.setHeaderFile(new URI("test://bad"));
 
@@ -236,7 +236,7 @@ public class HeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCacheHeaderFile() throws Exception {
+  void cacheHeaderFile() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(HeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputHeaderjava.header"));
 
@@ -254,7 +254,7 @@ public class HeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCacheHeaderWithoutFile() throws Exception {
+  void cacheHeaderWithoutFile() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(HeaderCheck.class);
     checkConfig.addProperty("header", "Test");
 
@@ -270,7 +270,7 @@ public class HeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreLinesSorted() throws Exception {
+  void ignoreLinesSorted() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(HeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputHeaderjava.header"));
     checkConfig.addProperty("ignoreLines", "4,2,3");
@@ -279,7 +279,7 @@ public class HeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLoadHeaderFileTwice() {
+  void loadHeaderFileTwice() {
     final HeaderCheck check = new HeaderCheck();
     check.setHeader("Header");
     final ReflectiveOperationException ex =
@@ -294,21 +294,21 @@ public class HeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHeaderIsValidWithBlankLines() throws Exception {
+  void headerIsValidWithBlankLines() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(HeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputHeaderjava.blank-lines.header"));
     verify(checkConfig, getPath("InputHeaderBlankLines.java"));
   }
 
   @Test
-  public void testHeaderIsValidWithBlankLinesBlockStyle() throws Exception {
+  void headerIsValidWithBlankLinesBlockStyle() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(HeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputHeaderjava.blank-lines2.header"));
     verify(checkConfig, getPath("InputHeaderBlankLines2.java"));
   }
 
   @Test
-  public void testExternalResource() throws Exception {
+  void externalResource() throws Exception {
     final HeaderCheck check = new HeaderCheck();
     final URI uri = CommonUtil.getUriByFilename(getPath("InputHeaderjava.header"));
     check.setHeaderFile(uri);
@@ -320,7 +320,7 @@ public class HeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIoExceptionWhenLoadingHeader() {
+  void ioExceptionWhenLoadingHeader() {
     final HeaderCheck check = new HeaderCheck();
     try (MockedConstruction<LineNumberReader> mocked =
         mockConstruction(
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/header/RegexpHeaderCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/header/RegexpHeaderCheckTest.java
@@ -34,7 +34,7 @@ import java.util.regex.Pattern;
 import org.junit.jupiter.api.Test;
 
 /** Unit test for RegexpHeaderCheck. */
-public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
+final class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -43,7 +43,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
 
   /** Test of setHeader method, of class RegexpHeaderCheck. */
   @Test
-  public void testSetHeaderNull() {
+  void setHeaderNull() {
     // check null passes
     final RegexpHeaderCheck instance = new RegexpHeaderCheck();
     // recreate for each test because multiple invocations fail
@@ -58,7 +58,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
 
   /** Test of setHeader method, of class RegexpHeaderCheck. */
   @Test
-  public void testSetHeaderEmpty() {
+  void setHeaderEmpty() {
     // check null passes
     final RegexpHeaderCheck instance = new RegexpHeaderCheck();
     // check empty string passes
@@ -73,7 +73,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
 
   /** Test of setHeader method, of class RegexpHeaderCheck. */
   @Test
-  public void testSetHeaderSimple() {
+  void setHeaderSimple() {
     final RegexpHeaderCheck instance = new RegexpHeaderCheck();
     // check valid header passes
     final String header = "abc.*";
@@ -87,7 +87,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
 
   /** Test of setHeader method, of class RegexpHeaderCheck. */
   @Test
-  public void testSetHeader() {
+  void setHeader() {
     // check invalid header passes
     final RegexpHeaderCheck instance = new RegexpHeaderCheck();
     try {
@@ -107,7 +107,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultConfiguration() throws Exception {
+  void defaultConfiguration() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     createChecker(checkConfig);
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -115,7 +115,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyFilename() throws Exception {
+  void emptyFilename() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("headerFile", "");
     try {
@@ -132,7 +132,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRegexpHeader() throws Exception {
+  void regexpHeader() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputRegexpHeader.header"));
     final String[] expected = {
@@ -142,7 +142,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonMatchingRegexpHeader() throws Exception {
+  void nonMatchingRegexpHeader() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("header", "\\/\\/ Nth Line of Header\\n\\/\\/ Nth Line of Header\\n");
     checkConfig.addProperty("multiLines", "1");
@@ -153,7 +153,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRegexpHeaderUrl() throws Exception {
+  void regexpHeaderUrl() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("headerFile", getUriString("InputRegexpHeader.header"));
     final String[] expected = {
@@ -163,7 +163,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInlineRegexpHeader() throws Exception {
+  void inlineRegexpHeader() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("header", "^/*$\\n// .*\\n// Created: 2002\\n^//.*\\n^//.*");
     final String[] expected = {
@@ -173,7 +173,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFailureForMultilineRegexp() throws Exception {
+  void failureForMultilineRegexp() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("header", "^(.*\\n.*)");
     try {
@@ -191,7 +191,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInlineRegexpHeaderConsecutiveNewlines() throws Exception {
+  void inlineRegexpHeaderConsecutiveNewlines() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("header", "^/*$\\n// .*\\n\\n// Created: 2017\\n^//.*");
     final String[] expected = {
@@ -201,7 +201,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInlineRegexpHeaderConsecutiveNewlinesThroughConfigFile() throws Exception {
+  void inlineRegexpHeaderConsecutiveNewlinesThroughConfigFile() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("headerFile", getUriString("InputRegexpHeaderNewLines.header"));
     final String[] expected = {
@@ -211,7 +211,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRegexpHeaderIgnore() throws Exception {
+  void regexpHeaderIgnore() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputRegexpHeader1.header"));
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -219,7 +219,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRegexpHeaderMulti1() throws Exception {
+  void regexpHeaderMulti1() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputRegexpHeader2.header"));
     checkConfig.addProperty("multiLines", "3, 6");
@@ -228,7 +228,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRegexpHeaderMulti2() throws Exception {
+  void regexpHeaderMulti2() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputRegexpHeader2.header"));
     checkConfig.addProperty("multiLines", "3, 6");
@@ -237,7 +237,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRegexpHeaderMulti3() throws Exception {
+  void regexpHeaderMulti3() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputRegexpHeader2.header"));
     checkConfig.addProperty("multiLines", "3, 7");
@@ -246,7 +246,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRegexpHeaderMulti4() throws Exception {
+  void regexpHeaderMulti4() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputRegexpHeader2.header"));
     checkConfig.addProperty("multiLines", "3, 5, 6, 7");
@@ -255,7 +255,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRegexpHeaderMulti5() throws Exception {
+  void regexpHeaderMulti5() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputRegexpHeader2.header"));
     checkConfig.addProperty("multiLines", "3");
@@ -266,7 +266,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRegexpHeaderMulti6() throws Exception {
+  void regexpHeaderMulti6() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputRegexpHeader2_4.header"));
     checkConfig.addProperty("multiLines", "8974382");
@@ -275,7 +275,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRegexpHeaderSmallHeader() throws Exception {
+  void regexpHeaderSmallHeader() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputRegexpHeader2.header"));
     checkConfig.addProperty("multiLines", "3, 6");
@@ -284,7 +284,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyMultiline() throws Exception {
+  void emptyMultiline() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputRegexpHeader2.header"));
     checkConfig.addProperty("multiLines", "");
@@ -295,7 +295,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRegexpHeaderMulti52() throws Exception {
+  void regexpHeaderMulti52() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputRegexpHeader3.header"));
     final String[] expected = {
@@ -305,7 +305,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreLinesSorted() throws Exception {
+  void ignoreLinesSorted() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputRegexpHeader5.header"));
     checkConfig.addProperty("multiLines", "7,5,3");
@@ -314,7 +314,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHeaderWithInvalidRegexp() throws Exception {
+  void headerWithInvalidRegexp() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputRegexpHeader.invalid.header"));
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -330,7 +330,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoWarningIfSingleLinedLeft() throws Exception {
+  void noWarningIfSingleLinedLeft() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputRegexpHeader4.header"));
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -338,7 +338,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoHeaderMissingErrorInCaseHeaderSizeEqualToFileSize() throws Exception {
+  void noHeaderMissingErrorInCaseHeaderSizeEqualToFileSize() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputRegexpHeader3.header"));
     checkConfig.addProperty("multiLines", "1");
@@ -349,7 +349,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCharsetProperty1() throws Exception {
+  void charsetProperty1() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputRegexpHeader7.header"));
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -358,7 +358,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCharsetProperty2() throws Exception {
+  void charsetProperty2() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("charset", "US-ASCII");
     checkConfig.addProperty("headerFile", getPath("InputRegexpHeader7.header"));
@@ -371,7 +371,7 @@ public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCharsetProperty3() throws Exception {
+  void charsetProperty3() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
     checkConfig.addProperty("headerFile", getPath("InputRegexpHeader7.header"));
     checkConfig.addProperty("charset", "US-ASCII");
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/AccessResultTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/AccessResultTest.java
@@ -23,14 +23,14 @@ import static com.google.common.truth.Truth.assertWithMessage;
 
 import org.junit.jupiter.api.Test;
 
-public class AccessResultTest {
+final class AccessResultTest {
 
   /* Additional test for jacoco, since valueOf()
    * is generated by javac and jacoco reports that
    * valueOf() is uncovered.
    */
   @Test
-  public void testAccessResultValueOf() {
+  void accessResultValueOf() {
     final AccessResult result = AccessResult.valueOf("ALLOWED");
     assertWithMessage("Invalid access result").that(result).isEqualTo(AccessResult.ALLOWED);
   }
@@ -40,7 +40,7 @@ public class AccessResultTest {
    * values() is uncovered.
    */
   @Test
-  public void testAccessResultValues() {
+  void accessResultValues() {
     final AccessResult[] actual = AccessResult.values();
     final AccessResult[] expected = {
       AccessResult.ALLOWED, AccessResult.DISALLOWED, AccessResult.UNKNOWN,
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/AvoidStarImportCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/AvoidStarImportCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class AvoidStarImportCheckTest extends AbstractModuleTestSupport {
+final class AvoidStarImportCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class AvoidStarImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultOperation() throws Exception {
+  void defaultOperation() throws Exception {
     final String[] expected = {
       "12:15: " + getCheckMessage(MSG_KEY, "java.io.*"),
       "13:17: " + getCheckMessage(MSG_KEY, "java.lang.*"),
@@ -47,7 +47,7 @@ public class AvoidStarImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExcludes() throws Exception {
+  void excludes() throws Exception {
     // allow the java.io/java.lang,javax.swing.WindowConstants star imports
     final String[] expected2 = {
       "31:27: " + getCheckMessage(MSG_KEY, "java.io.File.*"),
@@ -56,7 +56,7 @@ public class AvoidStarImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowClassImports() throws Exception {
+  void allowClassImports() throws Exception {
     // allow all class star imports
     final String[] expected2 = {
       "28:42: " + getCheckMessage(MSG_KEY, "javax.swing.WindowConstants.*"),
@@ -67,7 +67,7 @@ public class AvoidStarImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowStaticMemberImports() throws Exception {
+  void allowStaticMemberImports() throws Exception {
     // allow all static star imports
     final String[] expected2 = {
       "12:15: " + getCheckMessage(MSG_KEY, "java.io.*"),
@@ -77,7 +77,7 @@ public class AvoidStarImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final AvoidStarImportCheck testCheckObject = new AvoidStarImportCheck();
     final int[] actual = testCheckObject.getAcceptableTokens();
     final int[] expected = {TokenTypes.IMPORT, TokenTypes.STATIC_IMPORT};
@@ -85,7 +85,7 @@ public class AvoidStarImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final AvoidStarImportCheck testCheckObject = new AvoidStarImportCheck();
     final int[] actual = testCheckObject.getRequiredTokens();
     final int[] expected = {TokenTypes.IMPORT, TokenTypes.STATIC_IMPORT};
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/AvoidStaticImportCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/AvoidStaticImportCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class AvoidStaticImportCheckTest extends AbstractModuleTestSupport {
+final class AvoidStaticImportCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class AvoidStaticImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final AvoidStaticImportCheck checkObj = new AvoidStaticImportCheck();
     final int[] expected = {TokenTypes.STATIC_IMPORT};
     assertWithMessage("Default required tokens are invalid")
@@ -43,7 +43,7 @@ public class AvoidStaticImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultOperation() throws Exception {
+  void defaultOperation() throws Exception {
     final String[] expected = {
       "24:27: " + getCheckMessage(MSG_KEY, "java.io.File.listRoots"),
       "26:42: " + getCheckMessage(MSG_KEY, "javax.swing.WindowConstants.*"),
@@ -67,7 +67,7 @@ public class AvoidStaticImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStarExcludes() throws Exception {
+  void starExcludes() throws Exception {
     // allow the "java.io.File.*" AND "sun.net.ftpclient.FtpClient.*" star imports
     final String[] expected = {
       "26:42: " + getCheckMessage(MSG_KEY, "javax.swing.WindowConstants.*"),
@@ -88,7 +88,7 @@ public class AvoidStaticImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMemberExcludes() throws Exception {
+  void memberExcludes() throws Exception {
     // allow the java.io.File.listRoots and java.lang.Math.E member imports
     final String[] expected = {
       "26:42: " + getCheckMessage(MSG_KEY, "javax.swing.WindowConstants.*"),
@@ -110,7 +110,7 @@ public class AvoidStaticImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBogusMemberExcludes() throws Exception {
+  void bogusMemberExcludes() throws Exception {
     // should NOT mask anything
     final String[] expected = {
       "26:27: " + getCheckMessage(MSG_KEY, "java.io.File.listRoots"),
@@ -134,7 +134,7 @@ public class AvoidStaticImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInnerClassMemberExcludesStar() throws Exception {
+  void innerClassMemberExcludesStar() throws Exception {
     // should mask com.puppycrawl.tools.checkstyle.imports.avoidstaticimport.
     // InputAvoidStaticImportNestedClass.InnerClass.one
     final String[] expected = {
@@ -154,7 +154,7 @@ public class AvoidStaticImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final AvoidStaticImportCheck testCheckObject = new AvoidStaticImportCheck();
     final int[] actual = testCheckObject.getAcceptableTokens();
     final int[] expected = {TokenTypes.STATIC_IMPORT};
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/ClassImportRuleTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/ClassImportRuleTest.java
@@ -23,10 +23,10 @@ import static com.google.common.truth.Truth.assertWithMessage;
 
 import org.junit.jupiter.api.Test;
 
-public class ClassImportRuleTest {
+final class ClassImportRuleTest {
 
   @Test
-  public void testClassImportRule() {
+  void classImportRule() {
     final ClassImportRule rule = new ClassImportRule(true, false, "pkg.a", false);
     assertWithMessage("Class import rule should not be null").that(rule).isNotNull();
     assertWithMessage("Invalid access result")
@@ -50,7 +50,7 @@ public class ClassImportRuleTest {
   }
 
   @Test
-  public void testClassImportRuleRegexpSimple() {
+  void classImportRuleRegexpSimple() {
     final ClassImportRule rule = new ClassImportRule(true, false, "pkg.a", true);
     assertWithMessage("Class import rule should not be null").that(rule).isNotNull();
     assertWithMessage("Invalid access result")
@@ -74,7 +74,7 @@ public class ClassImportRuleTest {
   }
 
   @Test
-  public void testClassImportRuleRegexp() {
+  void classImportRuleRegexp() {
     final ClassImportRule rule = new ClassImportRule(true, false, "pk[gx]\\.a", true);
     assertWithMessage("Class import rule should not be null").that(rule).isNotNull();
     assertWithMessage("Invalid access result")
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/CustomImportOrderCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/CustomImportOrderCheckTest.java
@@ -38,7 +38,7 @@ import java.io.File;
 import java.lang.reflect.Method;
 import org.junit.jupiter.api.Test;
 
-public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
+final class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
 
   /** Shortcuts to make code more compact. */
   private static final String STATIC = CustomImportOrderCheck.STATIC_RULE_GROUP;
@@ -54,7 +54,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final CustomImportOrderCheck checkObj = new CustomImportOrderCheck();
     final int[] expected = {
       TokenTypes.IMPORT, TokenTypes.STATIC_IMPORT, TokenTypes.PACKAGE_DEF,
@@ -65,7 +65,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCustom() throws Exception {
+  void custom() throws Exception {
     final String[] expected = {
       "16:1: " + getCheckMessage(MSG_LEX, "java.awt.Button.ABORT", "java.io.File.createTempFile"),
       "17:1: " + getCheckMessage(MSG_LEX, "java.awt.print.Paper.*", "java.io.File.createTempFile"),
@@ -90,7 +90,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
    * configuration.
    */
   @Test
-  public void testStaticStandardThird() throws Exception {
+  void staticStandardThird() throws Exception {
     final String[] expected = {
       "16:1: " + getCheckMessage(MSG_LEX, "java.awt.Button.ABORT", "java.io.File.createTempFile"),
       "17:1: " + getCheckMessage(MSG_LEX, "java.awt.print.Paper.*", "java.io.File.createTempFile"),
@@ -109,7 +109,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticStandardThirdListCustomRules() throws Exception {
+  void staticStandardThirdListCustomRules() throws Exception {
     final String[] expected = {
       "16:1: " + getCheckMessage(MSG_LEX, "java.awt.Button.ABORT", "java.io.File.createTempFile"),
       "17:1: " + getCheckMessage(MSG_LEX, "java.awt.print.Paper.*", "java.io.File.createTempFile"),
@@ -128,7 +128,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticStandardThirdListCustomRulesWhitespace() throws Exception {
+  void staticStandardThirdListCustomRulesWhitespace() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -136,7 +136,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInputCustomImportOrderSingleLineList() throws Exception {
+  void inputCustomImportOrderSingleLineList() throws Exception {
     final String[] expected = {
       "14:112: " + getCheckMessage(MSG_LINE_SEPARATOR, "java.util.Map"),
       "15:1: " + getCheckMessage(MSG_LINE_SEPARATOR, "com.google.common.annotations.Beta"),
@@ -148,7 +148,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
 
   /** Checks different combinations for same_package group. */
   @Test
-  public void testNonSpecifiedImports() throws Exception {
+  void nonSpecifiedImports() throws Exception {
     final String[] expected = {
       "16:1: " + getCheckMessage(MSG_LEX, "java.awt.Button.ABORT", "java.io.File.createTempFile"),
       "17:1: " + getCheckMessage(MSG_LEX, "java.awt.print.Paper.*", "java.io.File.createTempFile"),
@@ -166,7 +166,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOrderRuleEmpty() throws Exception {
+  void orderRuleEmpty() throws Exception {
     final String[] expected = {
       "17:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.util.List"),
     };
@@ -175,7 +175,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOrderRuleWithOneGroup() throws Exception {
+  void orderRuleWithOneGroup() throws Exception {
     final String[] expected = {
       "16:1: " + getCheckMessage(MSG_LEX, "java.awt.Button.ABORT", "java.io.File.createTempFile"),
       "19:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.util.List"),
@@ -207,7 +207,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticSamePackage() throws Exception {
+  void staticSamePackage() throws Exception {
     final String[] expected = {
       "17:1: " + getCheckMessage(MSG_LEX, "java.util.*", "java.util.StringTokenizer"),
       "18:1: " + getCheckMessage(MSG_NONGROUP_EXPECTED, SAME, "java.util.concurrent.*"),
@@ -226,7 +226,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithoutLineSeparator() throws Exception {
+  void withoutLineSeparator() throws Exception {
     final String[] expected = {
       "17:1: " + getCheckMessage(MSG_LEX, "java.util.*", "java.util.StringTokenizer"),
       "18:1: " + getCheckMessage(MSG_NONGROUP_EXPECTED, SAME, "java.util.concurrent.*"),
@@ -245,7 +245,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithoutLineSeparator2() throws Exception {
+  void withoutLineSeparator2() throws Exception {
     final String[] expected = {
       "16:1: "
           + getCheckMessage(
@@ -261,14 +261,14 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoValid() throws Exception {
+  void noValid() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputCustomImportOrderNoValid.java"), expected);
   }
 
   @Test
-  public void testPossibleIndexOutOfBoundsException() throws Exception {
+  void possibleIndexOutOfBoundsException() throws Exception {
     final String[] expected = {
       "17:1: " + getCheckMessage(MSG_NONGROUP_EXPECTED, THIRD, "org.w3c.dom.Node"),
     };
@@ -278,7 +278,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultPackage2() throws Exception {
+  void defaultPackage2() throws Exception {
 
     final String[] expected = {
       "19:1: " + getCheckMessage(MSG_LEX, "java.awt.Button.ABORT", "java.io.File.createTempFile"),
@@ -301,7 +301,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithoutThirdPartyPackage() throws Exception {
+  void withoutThirdPartyPackage() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -309,7 +309,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testThirdPartyAndSpecialImports() throws Exception {
+  void thirdPartyAndSpecialImports() throws Exception {
     final String[] expected = {
       "23:1: "
           + getCheckMessage(MSG_ORDER, THIRD, SPECIAL, "com.google.common.collect.HashMultimap"),
@@ -320,7 +320,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCompareImports() throws Exception {
+  void compareImports() throws Exception {
     final String[] expected = {
       "16:1: " + getCheckMessage(MSG_LEX, "java.util.Map", "java.util.Map.Entry"),
     };
@@ -329,7 +329,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFindBetterPatternMatch() throws Exception {
+  void findBetterPatternMatch() throws Exception {
     final String[] expected = {
       "20:1: " + getCheckMessage(MSG_ORDER, THIRD, SPECIAL, "com.google.common.annotations.Beta"),
     };
@@ -339,7 +339,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBeginTreeClear() throws Exception {
+  void beginTreeClear() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(CustomImportOrderCheck.class);
     checkConfig.addProperty("specialImportsRegExp", "com");
     checkConfig.addProperty("separateLineBetweenGroups", "false");
@@ -355,7 +355,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testImportsContainingJava() throws Exception {
+  void importsContainingJava() throws Exception {
     final String[] expected = {
       "17:1: " + getCheckMessage(MSG_LINE_SEPARATOR, "com.google.errorprone.annotations.*"),
     };
@@ -365,7 +365,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final CustomImportOrderCheck testCheckObject = new CustomImportOrderCheck();
     final int[] actual = testCheckObject.getAcceptableTokens();
     final int[] expected = {
@@ -378,7 +378,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   @Test
   // UT uses Reflection to avoid removing null-validation from static method,
   // which is a candidate for utility method in the future
-  public void testGetFullImportIdent() throws Exception {
+  void getFullImportIdent() throws Exception {
     final Class<?> clazz = CustomImportOrderCheck.class;
     final Object t = clazz.getConstructor().newInstance();
     final Method method = clazz.getDeclaredMethod("getFullImportIdent", DetailAST.class);
@@ -390,7 +390,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSamePackageDepth2() throws Exception {
+  void samePackageDepth2() throws Exception {
     final String[] expected = {
       "20:1: " + getCheckMessage(MSG_NONGROUP_EXPECTED, SAME, "java.util.*"),
       "21:1: " + getCheckMessage(MSG_NONGROUP_EXPECTED, SAME, "java.util.List"),
@@ -410,7 +410,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSamePackageDepth3() throws Exception {
+  void samePackageDepth3() throws Exception {
     final String[] expected = {
       "23:1: " + getCheckMessage(MSG_NONGROUP_EXPECTED, SAME, "java.util.concurrent.*"),
       "24:1: "
@@ -425,7 +425,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSamePackageDepth4() throws Exception {
+  void samePackageDepth4() throws Exception {
     final String[] expected = {
       "25:1: "
           + getCheckMessage(MSG_NONGROUP_EXPECTED, SAME, "java.util.concurrent.locks.LockSupport"),
@@ -436,7 +436,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSamePackageDepthLongerThenActualPackage() throws Exception {
+  void samePackageDepthLongerThenActualPackage() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -444,7 +444,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSamePackageDepthNegative() throws Exception {
+  void samePackageDepthNegative() throws Exception {
 
     try {
       final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -469,7 +469,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSamePackageDepthZero() throws Exception {
+  void samePackageDepthZero() throws Exception {
     try {
       final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -492,7 +492,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUnsupportedRule() throws Exception {
+  void unsupportedRule() throws Exception {
     try {
       final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -514,7 +514,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSamePackageDepthNotInt() throws Exception {
+  void samePackageDepthNotInt() throws Exception {
     try {
       final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -536,14 +536,14 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoImports() throws Exception {
+  void noImports() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputCustomImportOrder_NoImports.java"), expected);
   }
 
   @Test
-  public void testDefaultConfiguration() throws Exception {
+  void defaultConfiguration() throws Exception {
     final String[] expected = {
       "20:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.awt.Button"),
       "32:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.io.*"),
@@ -553,7 +553,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRulesWithOverlappingPatterns() throws Exception {
+  void rulesWithOverlappingPatterns() throws Exception {
     final String[] expected = {
       "23:1: "
           + getCheckMessage(
@@ -596,28 +596,28 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMultiplePatternMatchesSecondPatternIsLonger() throws Exception {
+  void multiplePatternMatchesSecondPatternIsLonger() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputCustomImportOrder_MultiplePatternMatches.java"), expected);
   }
 
   @Test
-  public void testMultiplePatternMatchesFirstPatternHasLaterPosition() throws Exception {
+  void multiplePatternMatchesFirstPatternHasLaterPosition() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputCustomImportOrder_MultiplePatternMatches2.java"), expected);
   }
 
   @Test
-  public void testMultiplePatternMatchesFirstPatternHasEarlierPosition() throws Exception {
+  void multiplePatternMatchesFirstPatternHasEarlierPosition() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputCustomImportOrder_MultiplePatternMatches3.java"), expected);
   }
 
   @Test
-  public void testMultiplePatternMultipleImportFirstPatternHasLaterPosition() throws Exception {
+  void multiplePatternMultipleImportFirstPatternHasLaterPosition() throws Exception {
     final String[] expected = {
       "16:1: " + getCheckMessage(MSG_NONGROUP_EXPECTED, STD, "org.junit.Test"),
     };
@@ -626,7 +626,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoPackage() throws Exception {
+  void noPackage() throws Exception {
     final String[] expected = {
       "17:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.util.*"),
       "19:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.util.HashMap"),
@@ -638,7 +638,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoPackage2() throws Exception {
+  void noPackage2() throws Exception {
     final String[] expected = {
       "18:1: " + getCheckMessage(MSG_LINE_SEPARATOR, "com.sun.accessibility.internal.resources.*"),
       "22:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.util.Arrays"),
@@ -651,7 +651,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoPackage3() throws Exception {
+  void noPackage3() throws Exception {
     final String[] expected = {
       "17:1: " + getCheckMessage(MSG_LINE_SEPARATOR, "java.util.Map"),
       "25:1: " + getCheckMessage(MSG_LINE_SEPARATOR, "org.apache.*"),
@@ -662,7 +662,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInputCustomImportOrderSingleLine() throws Exception {
+  void inputCustomImportOrderSingleLine() throws Exception {
     final String[] expected = {
       "14:112: " + getCheckMessage(MSG_LINE_SEPARATOR, "java.util.Map"),
       "15:1: " + getCheckMessage(MSG_LINE_SEPARATOR, "com.google.common.annotations.Beta"),
@@ -673,7 +673,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInputCustomImportOrderSingleLine2() throws Exception {
+  void inputCustomImportOrderSingleLine2() throws Exception {
     final String[] expected = {
       "14:118: " + getCheckMessage(MSG_LINE_SEPARATOR, "java.util.Map"),
     };
@@ -682,7 +682,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInputCustomImportOrderThirdPartyAndSpecial2() throws Exception {
+  void inputCustomImportOrderThirdPartyAndSpecial2() throws Exception {
     final String[] expected = {
       "21:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "javax.swing.WindowConstants.*"),
       "24:1: " + getCheckMessage(MSG_LINE_SEPARATOR, "java.awt.Button"),
@@ -701,7 +701,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInputCustomImportOrderMultipleViolationsSameLine() throws Exception {
+  void inputCustomImportOrderMultipleViolationsSameLine() throws Exception {
     final String[] expected = {
       "17:1: " + getCheckMessage(MSG_NONGROUP_EXPECTED, STATIC, "java.util.Collections.*"),
       "18:1: "
@@ -715,7 +715,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInputCustomImportOrderSpanMultipleLines() throws Exception {
+  void inputCustomImportOrderSpanMultipleLines() throws Exception {
     final String[] expected = {
       "30:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.util.BitSet"),
       "45:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.util.HashSet"),
@@ -728,7 +728,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInputCustomImportOrderEclipseDefaultPositive() throws Exception {
+  void inputCustomImportOrderEclipseDefaultPositive() throws Exception {
     final String[] expected = {
       "22:1: " + getCheckMessage(MSG_NONGROUP_EXPECTED, STD, "java.awt.Button"),
       "23:1: " + getCheckMessage(MSG_NONGROUP_EXPECTED, STD, "java.awt.Dialog"),
@@ -744,7 +744,7 @@ public class CustomImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInputCustomImportOrderSpecialImportsRegExp() throws Exception {
+  void inputCustomImportOrderSpecialImportsRegExp() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputCustomImportOrderSpecialImportsRegExp.java"), expected);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/FileImportControlTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/FileImportControlTest.java
@@ -24,7 +24,7 @@ import static com.google.common.truth.Truth.assertWithMessage;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-public class FileImportControlTest {
+final class FileImportControlTest {
 
   private final PkgImportControl root =
       new PkgImportControl("com.kazgroup.courtlink", false, MismatchStrategy.DISALLOWED);
@@ -33,7 +33,7 @@ public class FileImportControlTest {
   private final FileImportControl fileRegexpNode = new FileImportControl(root, ".*Other.*", true);
 
   @BeforeEach
-  public void setUp() {
+  void setUp() {
     root.addChild(fileNode);
     root.addChild(fileRegexpNode);
 
@@ -43,7 +43,7 @@ public class FileImportControlTest {
   }
 
   @Test
-  public void testLocateFinest() {
+  void locateFinest() {
     assertWithMessage("Unexpected response")
         .that(root.locateFinest("com.kazgroup.courtlink.domain", "Random"))
         .isEqualTo(root);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/IllegalImportCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/IllegalImportCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class IllegalImportCheckTest extends AbstractModuleTestSupport {
+final class IllegalImportCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class IllegalImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final IllegalImportCheck checkObj = new IllegalImportCheck();
     final int[] expected = {TokenTypes.IMPORT, TokenTypes.STATIC_IMPORT};
     assertWithMessage("Default required tokens are invalid")
@@ -43,7 +43,7 @@ public class IllegalImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithSupplied() throws Exception {
+  void withSupplied() throws Exception {
     final String[] expected = {
       "12:1: " + getCheckMessage(MSG_KEY, "java.io.*"),
       "26:1: " + getCheckMessage(MSG_KEY, "java.io.File.listRoots"),
@@ -53,13 +53,13 @@ public class IllegalImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithDefault() throws Exception {
+  void withDefault() throws Exception {
     final String[] expected = {};
     verifyWithInlineConfigParser(getPath("InputIllegalImportDefault2.java"), expected);
   }
 
   @Test
-  public void testCustomSunPackageWithRegexp() throws Exception {
+  void customSunPackageWithRegexp() throws Exception {
     final String[] expected = {
       "17:1: " + getCheckMessage(MSG_KEY, "sun.reflect.*"),
     };
@@ -67,7 +67,7 @@ public class IllegalImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final IllegalImportCheck testCheckObject = new IllegalImportCheck();
     final int[] actual = testCheckObject.getAcceptableTokens();
     final int[] expected = {TokenTypes.IMPORT, TokenTypes.STATIC_IMPORT};
@@ -76,7 +76,7 @@ public class IllegalImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalClasses() throws Exception {
+  void illegalClasses() throws Exception {
     final String[] expected = {
       "14:1: " + getCheckMessage(MSG_KEY, "java.sql.Connection"),
       "18:1: " + getCheckMessage(MSG_KEY, "org.junit.jupiter.api.*"),
@@ -86,7 +86,7 @@ public class IllegalImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalClassesStarImport() throws Exception {
+  void illegalClassesStarImport() throws Exception {
     final String[] expected = {
       "12:1: " + getCheckMessage(MSG_KEY, "java.io.*"),
       "18:1: " + getCheckMessage(MSG_KEY, "org.junit.jupiter.api.*"),
@@ -96,7 +96,7 @@ public class IllegalImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalPackagesRegularExpression() throws Exception {
+  void illegalPackagesRegularExpression() throws Exception {
     final String[] expected = {
       "15:1: " + getCheckMessage(MSG_KEY, "java.util.List"),
       "16:1: " + getCheckMessage(MSG_KEY, "java.util.List"),
@@ -110,7 +110,7 @@ public class IllegalImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalClassesRegularExpression() throws Exception {
+  void illegalClassesRegularExpression() throws Exception {
     final String[] expected = {
       "15:1: " + getCheckMessage(MSG_KEY, "java.util.List"),
       "16:1: " + getCheckMessage(MSG_KEY, "java.util.List"),
@@ -120,7 +120,7 @@ public class IllegalImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalPackagesAndClassesRegularExpression() throws Exception {
+  void illegalPackagesAndClassesRegularExpression() throws Exception {
     final String[] expected = {
       "15:1: " + getCheckMessage(MSG_KEY, "java.util.List"),
       "16:1: " + getCheckMessage(MSG_KEY, "java.util.List"),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/ImportControlCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/ImportControlCheckTest.java
@@ -39,7 +39,7 @@ import java.util.List;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
 
-public class ImportControlCheckTest extends AbstractModuleTestSupport {
+final class ImportControlCheckTest extends AbstractModuleTestSupport {
 
   @TempDir public File temporaryFolder;
 
@@ -49,7 +49,7 @@ public class ImportControlCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final ImportControlCheck checkObj = new ImportControlCheck();
     final int[] expected = {
       TokenTypes.PACKAGE_DEF, TokenTypes.IMPORT, TokenTypes.STATIC_IMPORT,
@@ -60,14 +60,14 @@ public class ImportControlCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOne() throws Exception {
+  void one() throws Exception {
     final String[] expected = {"13:1: " + getCheckMessage(MSG_DISALLOWED, "java.io.File")};
 
     verifyWithInlineConfigParser(getPath("InputImportControl.java"), expected);
   }
 
   @Test
-  public void testTwo() throws Exception {
+  void two() throws Exception {
     final String[] expected = {
       "11:1: " + getCheckMessage(MSG_DISALLOWED, "java.awt.Image"),
       "12:1: " + getCheckMessage(MSG_DISALLOWED, "javax.swing.border.*"),
@@ -78,31 +78,31 @@ public class ImportControlCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWrong() throws Exception {
+  void wrong() throws Exception {
     final String[] expected = {"9:1: " + getCheckMessage(MSG_UNKNOWN_PKG)};
     verifyWithInlineConfigParser(getPath("InputImportControl3.java"), expected);
   }
 
   @Test
-  public void testMissing() throws Exception {
+  void missing() throws Exception {
     final String[] expected = {"9:1: " + getCheckMessage(MSG_MISSING_FILE)};
     verifyWithInlineConfigParser(getPath("InputImportControl4.java"), expected);
   }
 
   @Test
-  public void testEmpty() throws Exception {
+  void empty() throws Exception {
     final String[] expected = {"9:1: " + getCheckMessage(MSG_MISSING_FILE)};
     verifyWithInlineConfigParser(getPath("InputImportControl5.java"), expected);
   }
 
   @Test
-  public void testNull() throws Exception {
+  void testNull() throws Exception {
     final String[] expected = {"9:1: " + getCheckMessage(MSG_MISSING_FILE)};
     verifyWithInlineConfigParser(getPath("InputImportControl6.java"), expected);
   }
 
   @Test
-  public void testUnknown() throws Exception {
+  void unknown() throws Exception {
     try {
       final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
       verifyWithInlineConfigParser(getPath("InputImportControl7.java"), expected);
@@ -118,7 +118,7 @@ public class ImportControlCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBroken() throws Exception {
+  void broken() throws Exception {
     try {
       final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
       verifyWithInlineConfigParser(getPath("InputImportControl8.java"), expected);
@@ -134,14 +134,14 @@ public class ImportControlCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOneRegExp() throws Exception {
+  void oneRegExp() throws Exception {
     final String[] expected = {"13:1: " + getCheckMessage(MSG_DISALLOWED, "java.io.File")};
 
     verifyWithInlineConfigParser(getPath("InputImportControl9.java"), expected);
   }
 
   @Test
-  public void testTwoRegExp() throws Exception {
+  void twoRegExp() throws Exception {
     final String[] expected = {
       "11:1: " + getCheckMessage(MSG_DISALLOWED, "java.awt.Image"),
       "12:1: " + getCheckMessage(MSG_DISALLOWED, "javax.swing.border.*"),
@@ -152,14 +152,14 @@ public class ImportControlCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNotRegExpNoMatch() throws Exception {
+  void notRegExpNoMatch() throws Exception {
 
     verifyWithInlineConfigParser(
         getPath("InputImportControl11.java"), CommonUtil.EMPTY_STRING_ARRAY);
   }
 
   @Test
-  public void testBlacklist() throws Exception {
+  void blacklist() throws Exception {
     final String[] expected = {
       "11:1: " + getCheckMessage(MSG_DISALLOWED, "java.util.stream.Stream"),
       "12:1: " + getCheckMessage(MSG_DISALLOWED, "java.util.Date"),
@@ -171,7 +171,7 @@ public class ImportControlCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStrategyOnMismatchOne() throws Exception {
+  void strategyOnMismatchOne() throws Exception {
     final String[] expected = {
       "11:1: " + getCheckMessage(MSG_DISALLOWED, "java.awt.Image"),
       "12:1: " + getCheckMessage(MSG_DISALLOWED, "javax.swing.border.*"),
@@ -182,7 +182,7 @@ public class ImportControlCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStrategyOnMismatchTwo() throws Exception {
+  void strategyOnMismatchTwo() throws Exception {
     final String[] expected = {
       "11:1: " + getCheckMessage(MSG_DISALLOWED, "java.awt.Image"),
       "14:1: " + getCheckMessage(MSG_DISALLOWED, "java.awt.Button.ABORT"),
@@ -192,7 +192,7 @@ public class ImportControlCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStrategyOnMismatchThree() throws Exception {
+  void strategyOnMismatchThree() throws Exception {
     final String[] expected = {
       "11:1: " + getCheckMessage(MSG_DISALLOWED, "java.awt.Image"),
     };
@@ -201,7 +201,7 @@ public class ImportControlCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStrategyOnMismatchFour() throws Exception {
+  void strategyOnMismatchFour() throws Exception {
     final String[] expected = {
       "11:1: " + getCheckMessage(MSG_DISALLOWED, "java.awt.Image"),
       "12:1: " + getCheckMessage(MSG_DISALLOWED, "javax.swing.border.*"),
@@ -211,7 +211,7 @@ public class ImportControlCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithoutRegexAndWithStrategyOnMismatch() throws Exception {
+  void withoutRegexAndWithStrategyOnMismatch() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -219,28 +219,28 @@ public class ImportControlCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPkgRegExpInParent() throws Exception {
+  void pkgRegExpInParent() throws Exception {
     final String[] expected = {"13:1: " + getCheckMessage(MSG_DISALLOWED, "java.io.File")};
 
     verifyWithInlineConfigParser(getPath("InputImportControl16.java"), expected);
   }
 
   @Test
-  public void testPkgRegExpInChild() throws Exception {
+  void pkgRegExpInChild() throws Exception {
     final String[] expected = {"13:1: " + getCheckMessage(MSG_DISALLOWED, "java.io.File")};
 
     verifyWithInlineConfigParser(getPath("InputImportControl162.java"), expected);
   }
 
   @Test
-  public void testPkgRegExpInBoth() throws Exception {
+  void pkgRegExpInBoth() throws Exception {
     final String[] expected = {"13:1: " + getCheckMessage(MSG_DISALLOWED, "java.io.File")};
 
     verifyWithInlineConfigParser(getPath("InputImportControl163.java"), expected);
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final ImportControlCheck testCheckObject = new ImportControlCheck();
     final int[] actual = testCheckObject.getAcceptableTokens();
     final int[] expected = {
@@ -251,14 +251,14 @@ public class ImportControlCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testResource() throws Exception {
+  void resource() throws Exception {
     final String[] expected = {"13:1: " + getCheckMessage(MSG_DISALLOWED, "java.io.File")};
 
     verifyWithInlineConfigParser(getPath("InputImportControl17.java"), expected);
   }
 
   @Test
-  public void testResourceUnableToLoad() throws Exception {
+  void resourceUnableToLoad() throws Exception {
     try {
       final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
       verifyWithInlineConfigParser(getPath("InputImportControl18.java"), expected);
@@ -274,14 +274,14 @@ public class ImportControlCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUrlInFileProperty() throws Exception {
+  void urlInFileProperty() throws Exception {
     final String[] expected = {"13:1: " + getCheckMessage(MSG_DISALLOWED, "java.io.File")};
 
     verifyWithInlineConfigParser(getPath("InputImportControl19.java"), expected);
   }
 
   @Test
-  public void testUrlInFilePropertyUnableToLoad() throws Exception {
+  void urlInFilePropertyUnableToLoad() throws Exception {
 
     try {
       final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -298,7 +298,7 @@ public class ImportControlCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCacheWhenFileExternalResourceContentDoesNotChange() throws Exception {
+  void cacheWhenFileExternalResourceContentDoesNotChange() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(ImportControlCheck.class);
     checkConfig.addProperty("file", getPath("InputImportControlOneRegExp.xml"));
 
@@ -322,35 +322,35 @@ public class ImportControlCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPathRegexMatches() throws Exception {
+  void pathRegexMatches() throws Exception {
     final String[] expected = {"13:1: " + getCheckMessage(MSG_DISALLOWED, "java.io.File")};
 
     verifyWithInlineConfigParser(getPath("InputImportControl21.java"), expected);
   }
 
   @Test
-  public void testPathRegexMatchesPartially() throws Exception {
+  void pathRegexMatchesPartially() throws Exception {
     final String[] expected = {"13:1: " + getCheckMessage(MSG_DISALLOWED, "java.io.File")};
 
     verifyWithInlineConfigParser(getPath("InputImportControl22.java"), expected);
   }
 
   @Test
-  public void testPathRegexDoesntMatch() throws Exception {
+  void pathRegexDoesntMatch() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputImportControl23.java"), expected);
   }
 
   @Test
-  public void testPathRegexDoesntMatchPartially() throws Exception {
+  void pathRegexDoesntMatchPartially() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputImportControl24.java"), expected);
   }
 
   @Test
-  public void testDisallowClassOfAllowPackage() throws Exception {
+  void disallowClassOfAllowPackage() throws Exception {
     final String[] expected = {
       "12:1: " + getCheckMessage(MSG_DISALLOWED, "java.util.Date"),
     };
@@ -360,7 +360,7 @@ public class ImportControlCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFileName() throws Exception {
+  void fileName() throws Exception {
     final String[] expected = {
       "11:1: " + getCheckMessage(MSG_DISALLOWED, "java.awt.Image"),
     };
@@ -369,7 +369,7 @@ public class ImportControlCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithRegex() throws Exception {
+  void withRegex() throws Exception {
     final String[] expected = {
       "11:1: " + getCheckMessage(MSG_DISALLOWED, "java.io.File"),
     };
@@ -378,7 +378,7 @@ public class ImportControlCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFileNameNoExtension() throws Exception {
+  void fileNameNoExtension() throws Exception {
     final String[] expected = {
       "13:1: " + getCheckMessage(MSG_DISALLOWED, "java.awt.Image"),
     };
@@ -387,7 +387,7 @@ public class ImportControlCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBeginTreeCurrentImportControl() throws Exception {
+  void beginTreeCurrentImportControl() throws Exception {
     final String file1 = getPath("InputImportControlBeginTree1.java");
     final String file2 = getPath("InputImportControlBeginTree2.java");
     final List<String> expectedFirstInput =
@@ -399,7 +399,7 @@ public class ImportControlCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testImportControlFileName() throws Exception {
+  void importControlFileName() throws Exception {
     final String[] expected = {
       "11:1: " + getCheckMessage(MSG_DISALLOWED, "java.awt.Image"),
     };
@@ -408,14 +408,14 @@ public class ImportControlCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testImportControlFileName2() throws Exception {
+  void importControlFileName2() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputImportControlTestRegexpInFile2.java"), expected);
   }
 
   @Test
-  public void testImportControlTestException() {
+  void importControlTestException() {
     final CheckstyleException ex =
         assertThrows(
             CheckstyleException.class,
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/ImportControlLoaderTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/ImportControlLoaderTest.java
@@ -40,7 +40,7 @@ import org.xml.sax.SAXException;
 import org.xml.sax.SAXParseException;
 import org.xml.sax.helpers.AttributesImpl;
 
-public class ImportControlLoaderTest {
+final class ImportControlLoaderTest {
 
   private static String getPath(String filename) {
     return "src/test/resources/com/puppycrawl/tools/"
@@ -49,14 +49,14 @@ public class ImportControlLoaderTest {
   }
 
   @Test
-  public void testLoad() throws CheckstyleException {
+  void load() throws CheckstyleException {
     final AbstractImportControl root =
         ImportControlLoader.load(new File(getPath("InputImportControlLoaderComplete.xml")).toURI());
     assertWithMessage("Import root should not be null").that(root).isNotNull();
   }
 
   @Test
-  public void testWrongFormatUri() throws Exception {
+  void wrongFormatUri() throws Exception {
     try {
       ImportControlLoader.load(new URI("aaa://" + getPath("InputImportControlLoaderComplete.xml")));
       assertWithMessage("exception expected").fail();
@@ -73,7 +73,7 @@ public class ImportControlLoaderTest {
   }
 
   @Test
-  public void testExtraElementInConfig() throws Exception {
+  void extraElementInConfig() throws Exception {
     final AbstractImportControl root =
         ImportControlLoader.load(
             new File(getPath("InputImportControlLoaderWithNewElement.xml")).toURI());
@@ -82,7 +82,7 @@ public class ImportControlLoaderTest {
 
   @Test
   // UT uses Reflection to avoid removing null-validation from static method
-  public void testSafeGetThrowsException() {
+  void safeGetThrowsException() {
     final AttributesImpl attr =
         new AttributesImpl() {
           @Override
@@ -113,7 +113,7 @@ public class ImportControlLoaderTest {
   // UT uses Reflection to cover IOException from 'loader.parseInputSource(source);'
   // because this is possible situation (though highly unlikely), which depends on hardware
   // and is difficult to emulate
-  public void testLoadThrowsException() {
+  void loadThrowsException() {
     final InputSource source = new InputSource();
     try {
       final Class<?> clazz = ImportControlLoader.class;
@@ -135,7 +135,7 @@ public class ImportControlLoaderTest {
   }
 
   @Test
-  public void testInputStreamFailsOnRead() throws Exception {
+  void inputStreamFailsOnRead() throws Exception {
     try (InputStream inputStream = mock()) {
       final int available = doThrow(IOException.class).when(inputStream).available();
       final URL url = mock();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/ImportOrderCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/ImportOrderCheckTest.java
@@ -38,7 +38,7 @@ import java.util.Optional;
 import org.antlr.v4.runtime.CommonToken;
 import org.junit.jupiter.api.Test;
 
-public class ImportOrderCheckTest extends AbstractModuleTestSupport {
+final class ImportOrderCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -46,14 +46,14 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testVeryPreciseGrouping() throws Exception {
+  void veryPreciseGrouping() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getNonCompilablePath("InputImportOrder6.java"), expected);
   }
 
   @Test
-  public void testGetTokens() {
+  void getTokens() {
     final ImportOrderCheck checkObj = new ImportOrderCheck();
     final int[] expected = {TokenTypes.IMPORT, TokenTypes.STATIC_IMPORT};
     assertWithMessage("Default tokens differs from expected")
@@ -72,13 +72,13 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
    * valueOf() is uncovered.
    */
   @Test
-  public void testImportOrderOptionValueOf() {
+  void importOrderOptionValueOf() {
     final ImportOrderOption option = ImportOrderOption.valueOf("TOP");
     assertWithMessage("Invalid valueOf result").that(option).isEqualTo(ImportOrderOption.TOP);
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "21:1: " + getCheckMessage(MSG_ORDERING, "java.awt.Dialog"),
       "25:1: " + getCheckMessage(MSG_ORDERING, "javax.swing.JComponent"),
@@ -92,7 +92,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWrongSequenceInNonStaticImports() throws Exception {
+  void wrongSequenceInNonStaticImports() throws Exception {
 
     final String[] expected = {
       "19:1: " + getCheckMessage(MSG_ORDERING, "java.util.HashMap"),
@@ -103,14 +103,14 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMultilineImport() throws Exception {
+  void multilineImport() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getNonCompilablePath("InputImportOrderMultiline.java"), expected);
   }
 
   @Test
-  public void testGroups() throws Exception {
+  void groups() throws Exception {
     final String[] expected = {
       "21:1: " + getCheckMessage(MSG_ORDERING, "java.awt.Dialog"),
       "29:1: " + getCheckMessage(MSG_ORDERING, "java.io.IOException"),
@@ -123,7 +123,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGroupsRegexp() throws Exception {
+  void groupsRegexp() throws Exception {
     final String[] expected = {
       "27:1: " + getCheckMessage(MSG_ORDERING, "java.io.File"),
       "34:1: "
@@ -134,7 +134,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSeparated() throws Exception {
+  void separated() throws Exception {
     final String[] expected = {
       "25:1: " + getCheckMessage(MSG_SEPARATION, "javax.swing.JComponent"),
       "27:1: " + getCheckMessage(MSG_SEPARATION, "java.io.File"),
@@ -145,7 +145,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticImportSeparated() throws Exception {
+  void staticImportSeparated() throws Exception {
     final String[] expected = {
       "21:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.lang.Math.cos"),
       "23:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "org.junit.Assert.assertEquals"),
@@ -155,7 +155,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoGapBetweenStaticImports() throws Exception {
+  void noGapBetweenStaticImports() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -163,7 +163,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSortStaticImportsAlphabeticallyFalse() throws Exception {
+  void sortStaticImportsAlphabeticallyFalse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -171,7 +171,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSortStaticImportsAlphabeticallyTrue() throws Exception {
+  void sortStaticImportsAlphabeticallyTrue() throws Exception {
     final String[] expected = {
       "20:1: "
           + getCheckMessage(MSG_ORDERING, "javax.xml.transform.TransformerFactory.newInstance"),
@@ -184,14 +184,14 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCaseInsensitive() throws Exception {
+  void caseInsensitive() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputImportOrderCaseInsensitive.java"), expected);
   }
 
   @Test
-  public void testContainerCaseInsensitive() throws Exception {
+  void containerCaseInsensitive() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -199,7 +199,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSimilarGroupPattern() throws Exception {
+  void similarGroupPattern() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -207,7 +207,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidOption() throws Exception {
+  void invalidOption() throws Exception {
 
     try {
       final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -226,7 +226,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTop() throws Exception {
+  void top() throws Exception {
     final String[] expected = {
       "23:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.awt.Button"),
       "28:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.io.IOException"),
@@ -239,7 +239,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAbove() throws Exception {
+  void above() throws Exception {
     final String[] expected = {
       "21:1: " + getCheckMessage(MSG_ORDERING, "java.awt.Button.ABORT"),
       "24:1: " + getCheckMessage(MSG_ORDERING, "java.awt.Dialog"),
@@ -252,7 +252,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInFlow() throws Exception {
+  void inFlow() throws Exception {
     final String[] expected = {
       "22:1: " + getCheckMessage(MSG_ORDERING, "java.awt.Dialog"),
       "25:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "javax.swing.JComponent"),
@@ -268,7 +268,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUnder() throws Exception {
+  void under() throws Exception {
     // is default (testDefault)
     final String[] expected = {
       "21:1: " + getCheckMessage(MSG_ORDERING, "java.awt.Dialog"),
@@ -281,7 +281,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBottom() throws Exception {
+  void bottom() throws Exception {
     final String[] expected = {
       "24:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.io.IOException"),
       "27:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "javax.swing.JComponent"),
@@ -296,7 +296,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetGroupNumber() throws Exception {
+  void getGroupNumber() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -304,7 +304,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHonorsTokenProperty() throws Exception {
+  void honorsTokenProperty() throws Exception {
     final String[] expected = {
       "20:1: " + getCheckMessage(MSG_ORDERING, "java.awt.Button.ABORT"),
       "21:1: " + getCheckMessage(MSG_ORDERING, "java.awt.Dialog"),
@@ -315,7 +315,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWildcard() throws Exception {
+  void wildcard() throws Exception {
     final String[] expected = {
       "24:1: " + getCheckMessage(MSG_ORDERING, "javax.crypto.Cipher"),
     };
@@ -324,7 +324,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWildcardUnspecified() throws Exception {
+  void wildcardUnspecified() throws Exception {
     final String[] expected = {
       "23:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "javax.crypto.Cipher"),
     };
@@ -333,14 +333,14 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoFailureForRedundantImports() throws Exception {
+  void noFailureForRedundantImports() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputImportOrder_NoFailureForRedundantImports.java"), expected);
   }
 
   @Test
-  public void testStaticGroupsAlphabeticalOrder() throws Exception {
+  void staticGroupsAlphabeticalOrder() throws Exception {
     final String[] expected = {
       "22:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "org.antlr.v4.runtime.*"),
       "24:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.util.Set"),
@@ -350,7 +350,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticGroupsOrder() throws Exception {
+  void staticGroupsOrder() throws Exception {
     final String[] expected = {
       "22:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "org.antlr.v4.runtime.*"),
       "24:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.util.Set"),
@@ -359,7 +359,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticGroupsAlphabeticalOrderBottom() throws Exception {
+  void staticGroupsAlphabeticalOrderBottom() throws Exception {
     final String[] expected = {
       "21:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.util.Set"),
       "23:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.lang.Math.PI"),
@@ -368,7 +368,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticGroupsAlphabeticalOrderBottomNegative() throws Exception {
+  void staticGroupsAlphabeticalOrderBottomNegative() throws Exception {
     final String[] expected = {
       "24:1: " + getCheckMessage(MSG_ORDERING, "java.util.Set"),
     };
@@ -380,7 +380,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
    * Tests that a non-static import after a static import correctly gives an error if order=bottom.
    */
   @Test
-  public void testStaticGroupsAlphabeticalOrderTopNegative() throws Exception {
+  void staticGroupsAlphabeticalOrderTopNegative() throws Exception {
     final String[] expected = {
       "21:1: " + getCheckMessage(MSG_ORDERING, "java.lang.Math.PI"),
     };
@@ -392,7 +392,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
    * Tests that a non-static import before a static import correctly gives an error if order=top.
    */
   @Test
-  public void testStaticGroupsAlphabeticalOrderBottomNegative2() throws Exception {
+  void staticGroupsAlphabeticalOrderBottomNegative2() throws Exception {
     final String[] expected = {
       "24:1: " + getCheckMessage(MSG_ORDERING, "java.util.Set"),
     };
@@ -401,7 +401,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticGroupsOrderBottom() throws Exception {
+  void staticGroupsOrderBottom() throws Exception {
     final String[] expected = {
       "21:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.util.Set"),
       "23:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.lang.Math.PI"),
@@ -410,19 +410,19 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testImportReception() throws Exception {
+  void importReception() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputImportOrderRepetition.java"), expected);
   }
 
   @Test
-  public void testStaticImportReceptionTop() throws Exception {
+  void staticImportReceptionTop() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputImportOrderStaticRepetition1.java"), expected);
   }
 
   @Test
-  public void testStaticImportReception() throws Exception {
+  void staticImportReception() throws Exception {
     final String[] expected = {
       "20:1: " + getCheckMessage(MSG_SEPARATION, "org.antlr.v4.runtime.CommonToken.*"),
       "23:1: " + getCheckMessage(MSG_ORDERING, "java.util.Set"),
@@ -431,7 +431,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticGroupsOrderAbove() throws Exception {
+  void staticGroupsOrderAbove() throws Exception {
     final String[] expected = {
       "21:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.util.Set"),
       "23:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.lang.Math.PI"),
@@ -442,7 +442,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticOnDemandGroupsOrder() throws Exception {
+  void staticOnDemandGroupsOrder() throws Exception {
     final String[] expected = {
       "22:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "org.antlr.v4.runtime.*"),
       "24:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.util.Set"),
@@ -453,7 +453,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticOnDemandGroupsAlphabeticalOrder() throws Exception {
+  void staticOnDemandGroupsAlphabeticalOrder() throws Exception {
     final String[] expected = {
       "22:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "org.antlr.v4.runtime.*"),
       "24:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.util.Set"),
@@ -464,7 +464,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticOnDemandGroupsOrderBottom() throws Exception {
+  void staticOnDemandGroupsOrderBottom() throws Exception {
     final String[] expected = {
       "21:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.util.Set"),
       "23:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.lang.Math.*"),
@@ -474,7 +474,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticOnDemandGroupsAlphabeticalOrderBottom() throws Exception {
+  void staticOnDemandGroupsAlphabeticalOrderBottom() throws Exception {
     final String[] expected = {
       "21:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.util.Set"),
       "23:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.lang.Math.*"),
@@ -484,7 +484,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticOnDemandGroupsOrderAbove() throws Exception {
+  void staticOnDemandGroupsOrderAbove() throws Exception {
     final String[] expected = {
       "21:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.util.Set"),
       "23:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "java.lang.Math.*"),
@@ -496,7 +496,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGroupWithSlashes() throws Exception {
+  void groupWithSlashes() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(ImportOrderCheck.class);
     checkConfig.addProperty("groups", "/^javax");
 
@@ -518,7 +518,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGroupWithDot() throws Exception {
+  void groupWithDot() throws Exception {
     final String[] expected = {
       "21:1: " + getCheckMessage(MSG_ORDERING, "java.awt.Dialog"),
       "23:1: " + getCheckMessage(MSG_ORDERING, "javax.swing.JComponent"),
@@ -527,7 +527,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMultiplePatternMatches() throws Exception {
+  void multiplePatternMatches() throws Exception {
     final String[] expected = {
       "21:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "org.*"),
     };
@@ -543,7 +543,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
    * given, so there is no other way to cover this code.
    */
   @Test
-  public void testVisitTokenSwitchReflection() {
+  void visitTokenSwitchReflection() {
     // Create mock ast
     final DetailAstImpl astImport = mockAST(TokenTypes.IMPORT, "import", 0, 0);
     final DetailAstImpl astIdent = mockAST(TokenTypes.IDENT, "myTestImport", 0, 0);
@@ -584,7 +584,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEclipseDefaultPositive() throws Exception {
+  void eclipseDefaultPositive() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -592,14 +592,14 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticImportEclipseRepetition() throws Exception {
+  void staticImportEclipseRepetition() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getNonCompilablePath("InputImportOrderEclipseStaticRepetition.java"), expected);
   }
 
   @Test
-  public void testEclipseDefaultNegative() throws Exception {
+  void eclipseDefaultNegative() throws Exception {
     final String[] expected = {
       "28:1: " + getCheckMessage(MSG_SEPARATION, "javax.swing.JComponent"),
       "33:1: " + getCheckMessage(MSG_ORDERING, "org.junit.Test"),
@@ -610,14 +610,14 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUseContainerOrderingForStaticTrue() throws Exception {
+  void useContainerOrderingForStaticTrue() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getNonCompilablePath("InputImportOrderEclipseStatic1.java"), expected);
   }
 
   @Test
-  public void testUseContainerOrderingForStaticFalse() throws Exception {
+  void useContainerOrderingForStaticFalse() throws Exception {
     final String[] expected = {
       "22:1: "
           + getCheckMessage(MSG_ORDERING, "io.netty.handler.codec.http.HttpHeaders.Names.addDate"),
@@ -627,7 +627,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUseContainerOrderingForStaticTrueCaseSensitive() throws Exception {
+  void useContainerOrderingForStaticTrueCaseSensitive() throws Exception {
     final String[] expected = {
       "23:1: "
           + getCheckMessage(MSG_ORDERING, "io.netty.handler.codec.http.HttpHeaders.Names.DATE"),
@@ -637,7 +637,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUseContainerOrderingForStatic() throws Exception {
+  void useContainerOrderingForStatic() throws Exception {
     final String[] expected = {
       "22:1: " + getCheckMessage(MSG_ORDERING, "io.netty.handler.Codec.HTTP.HttpHeaders.tmp.same"),
       "23:1: " + getCheckMessage(MSG_ORDERING, "io.netty.handler.Codec.HTTP.HttpHeaders.TKN.same"),
@@ -647,7 +647,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testImportGroupsRedundantSeparatedInternally() throws Exception {
+  void importGroupsRedundantSeparatedInternally() throws Exception {
     final String[] expected = {
       "21:1: " + getCheckMessage(MSG_SEPARATED_IN_GROUP, "org.*"),
     };
@@ -656,7 +656,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticGroupsAbove() throws Exception {
+  void staticGroupsAbove() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -664,7 +664,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticGroupsBottom() throws Exception {
+  void staticGroupsBottom() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -672,7 +672,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticGroupsBottomSeparated() throws Exception {
+  void staticGroupsBottomSeparated() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -680,7 +680,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticGroupsInflow() throws Exception {
+  void staticGroupsInflow() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -688,7 +688,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticGroupsNegative() throws Exception {
+  void staticGroupsNegative() throws Exception {
     final String[] expected = {
       "21:1: " + getCheckMessage(MSG_ORDERING, "org.junit.Assert.fail"),
       "23:1: " + getCheckMessage(MSG_ORDERING, "org.infinispan.test.TestingUtil.extract"),
@@ -699,7 +699,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticGroupsTop() throws Exception {
+  void staticGroupsTop() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -707,7 +707,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticGroupsTopSeparated() throws Exception {
+  void staticGroupsTopSeparated() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -715,7 +715,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticGroupsUnordered() throws Exception {
+  void staticGroupsUnordered() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -723,7 +723,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTrimOption() throws Exception {
+  void trimOption() throws Exception {
     final String[] expected = {
       "25:1: " + getCheckMessage(MSG_ORDERING, "java.util.Set"),
     };
@@ -739,7 +739,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
    * @throws Exception when code tested throws exception
    */
   @Test
-  public void testClearState() throws Exception {
+  void clearState() throws Exception {
     final ImportOrderCheck check = new ImportOrderCheck();
     final DetailAST root =
         JavaParser.parseFile(
@@ -753,7 +753,7 @@ public class ImportOrderCheckTest extends AbstractModuleTestSupport {
         .that(
             TestUtil.isStatefulFieldClearedDuringBeginTree(
                 check,
-                staticImport.get(),
+                staticImport.orElseThrow(),
                 "lastImportStatic",
                 lastImportStatic -> !((boolean) lastImportStatic)))
         .isTrue();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/PkgImportControlTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/PkgImportControlTest.java
@@ -24,7 +24,7 @@ import static com.google.common.truth.Truth.assertWithMessage;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-public class PkgImportControlTest {
+final class PkgImportControlTest {
 
   private final PkgImportControl icRoot =
       new PkgImportControl("com.kazgroup.courtlink", false, MismatchStrategy.DISALLOWED);
@@ -44,7 +44,7 @@ public class PkgImportControlTest {
       new PkgImportControl(icRootRegexpParent, "bo+t", true, MismatchStrategy.DELEGATE_TO_PARENT);
 
   @BeforeEach
-  public void setUp() {
+  void setUp() {
     icRoot.addChild(icCommon);
     icRoot.addImportRule(new PkgImportRule(false, false, "org.springframework", false, false));
     icRoot.addImportRule(new PkgImportRule(false, false, "org.hibernate", false, false));
@@ -66,14 +66,14 @@ public class PkgImportControlTest {
   }
 
   @Test
-  public void testDotMetaCharacter() {
+  void dotMetaCharacter() {
     assertWithMessage("Unexpected response")
         .that(icUncommon.locateFinest("com-kazgroup.courtlink.uncommon.regexp", "MyClass"))
         .isNull();
   }
 
   @Test
-  public void testLocateFinest() {
+  void locateFinest() {
     assertWithMessage("Unexpected response")
         .that(icRoot.locateFinest("com.kazgroup.courtlink.domain", "MyClass"))
         .isEqualTo(icRoot);
@@ -84,7 +84,7 @@ public class PkgImportControlTest {
   }
 
   @Test
-  public void testEnsureTrailingDot() {
+  void ensureTrailingDot() {
     assertWithMessage("Unexpected response")
         .that(icRoot.locateFinest("com.kazgroup.courtlinkkk", "MyClass"))
         .isNull();
@@ -94,7 +94,7 @@ public class PkgImportControlTest {
   }
 
   @Test
-  public void testCheckAccess() {
+  void checkAccess() {
     assertWithMessage("Unexpected access result")
         .that(
             icCommon.checkAccess(
@@ -125,14 +125,14 @@ public class PkgImportControlTest {
   }
 
   @Test
-  public void testUnknownPkg() {
+  void unknownPkg() {
     assertWithMessage("Unexpected response")
         .that(icRoot.locateFinest("net.another", "MyClass"))
         .isNull();
   }
 
   @Test
-  public void testRegExpChildLocateFinest() {
+  void regExpChildLocateFinest() {
     assertWithMessage("Unexpected response")
         .that(icRootRegexpChild.locateFinest("com.kazgroup.courtlink.domain", "MyClass"))
         .isEqualTo(icRootRegexpChild);
@@ -145,7 +145,7 @@ public class PkgImportControlTest {
   }
 
   @Test
-  public void testRegExpChildCheckAccess() {
+  void regExpChildCheckAccess() {
     assertWithMessage("Unexpected access result")
         .that(
             icCommonRegexpChild.checkAccess(
@@ -204,14 +204,14 @@ public class PkgImportControlTest {
   }
 
   @Test
-  public void testRegExpChildUnknownPkg() {
+  void regExpChildUnknownPkg() {
     assertWithMessage("Unexpected response")
         .that(icRootRegexpChild.locateFinest("net.another", "MyClass"))
         .isNull();
   }
 
   @Test
-  public void testRegExpParentInRootIsConsidered() {
+  void regExpParentInRootIsConsidered() {
     assertWithMessage("Package should not be null")
         .that(icRootRegexpParent.locateFinest("com", "MyClass"))
         .isNull();
@@ -230,7 +230,7 @@ public class PkgImportControlTest {
   }
 
   @Test
-  public void testRegExpParentInSubpackageIsConsidered() {
+  void regExpParentInSubpackageIsConsidered() {
     assertWithMessage("Invalid package")
         .that(icRootRegexpParent.locateFinest("com.kazgroup.courtlink.boot.api", "MyClass"))
         .isEqualTo(icBootRegexpParen);
@@ -240,7 +240,7 @@ public class PkgImportControlTest {
   }
 
   @Test
-  public void testRegExpParentEnsureTrailingDot() {
+  void regExpParentEnsureTrailingDot() {
     assertWithMessage("Invalid package")
         .that(icRootRegexpParent.locateFinest("com.kazgroup.courtlinkkk", "MyClass"))
         .isNull();
@@ -250,7 +250,7 @@ public class PkgImportControlTest {
   }
 
   @Test
-  public void testRegExpParentAlternationInParentIsHandledCorrectly() {
+  void regExpParentAlternationInParentIsHandledCorrectly() {
     // the regular expression has to be adjusted to (com\.foo|com\.bar)
     final PkgImportControl root =
         new PkgImportControl("com\\.foo|com\\.bar", true, MismatchStrategy.DISALLOWED);
@@ -272,7 +272,7 @@ public class PkgImportControlTest {
   }
 
   @Test
-  public void testRegExpParentAlternationInParentIfUserCaresForIt() {
+  void regExpParentAlternationInParentIfUserCaresForIt() {
     // the regular expression has to be adjusted to (com\.foo|com\.bar)
     final PkgImportControl root =
         new PkgImportControl("(com\\.foo|com\\.bar)", true, MismatchStrategy.DISALLOWED);
@@ -294,7 +294,7 @@ public class PkgImportControlTest {
   }
 
   @Test
-  public void testRegExpParentAlternationInSubpackageIsHandledCorrectly() {
+  void regExpParentAlternationInSubpackageIsHandledCorrectly() {
     final PkgImportControl root =
         new PkgImportControl("org.somewhere", false, MismatchStrategy.DISALLOWED);
     // the regular expression has to be adjusted to (foo|bar)
@@ -313,7 +313,7 @@ public class PkgImportControlTest {
   }
 
   @Test
-  public void testRegExpParentUnknownPkg() {
+  void regExpParentUnknownPkg() {
     assertWithMessage("Package should not be null")
         .that(icRootRegexpParent.locateFinest("net.another", "MyClass"))
         .isNull();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/PkgImportRuleTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/PkgImportRuleTest.java
@@ -23,10 +23,10 @@ import static com.google.common.truth.Truth.assertWithMessage;
 
 import org.junit.jupiter.api.Test;
 
-public class PkgImportRuleTest {
+final class PkgImportRuleTest {
 
   @Test
-  public void testPkgImportRule() {
+  void pkgImportRule() {
     final PkgImportRule rule = new PkgImportRule(true, false, "pkg", false, false);
     assertWithMessage("Rule must not be null").that(rule).isNotNull();
     assertWithMessage("Invalid access result")
@@ -50,7 +50,7 @@ public class PkgImportRuleTest {
   }
 
   @Test
-  public void testPkgImportRuleExactMatch() {
+  void pkgImportRuleExactMatch() {
     final PkgImportRule rule = new PkgImportRule(true, false, "pkg", true, false);
     assertWithMessage("Rule must not be null").that(rule).isNotNull();
     assertWithMessage("Invalid access result")
@@ -71,7 +71,7 @@ public class PkgImportRuleTest {
   }
 
   @Test
-  public void testPkgImportRuleRegexpSimple() {
+  void pkgImportRuleRegexpSimple() {
     final PkgImportRule rule = new PkgImportRule(true, false, "pkg", false, true);
     assertWithMessage("Rule must not be null").that(rule).isNotNull();
     assertWithMessage("Invalid access result")
@@ -95,7 +95,7 @@ public class PkgImportRuleTest {
   }
 
   @Test
-  public void testPkgImportRuleExactMatchRegexpSimple() {
+  void pkgImportRuleExactMatchRegexpSimple() {
     final PkgImportRule rule = new PkgImportRule(true, false, "pkg", true, true);
     assertWithMessage("Rule must not be null").that(rule).isNotNull();
     assertWithMessage("Invalid access result")
@@ -116,7 +116,7 @@ public class PkgImportRuleTest {
   }
 
   @Test
-  public void testPkgImportRuleRegexp() {
+  void pkgImportRuleRegexp() {
     final PkgImportRule rule = new PkgImportRule(true, false, "(pkg|hallo)", false, true);
     assertWithMessage("Rule must not be null").that(rule).isNotNull();
     assertWithMessage("Invalid access result")
@@ -152,7 +152,7 @@ public class PkgImportRuleTest {
   }
 
   @Test
-  public void testPkgImportRuleNoRegexp() {
+  void pkgImportRuleNoRegexp() {
     final PkgImportRule rule = new PkgImportRule(true, false, "(pkg|hallo)", false, false);
     assertWithMessage("Rule must not be null").that(rule).isNotNull();
     assertWithMessage("Invalid access result")
@@ -185,7 +185,7 @@ public class PkgImportRuleTest {
   }
 
   @Test
-  public void testPkgImportRuleExactMatchRegexp() {
+  void pkgImportRuleExactMatchRegexp() {
     final PkgImportRule rule = new PkgImportRule(true, false, "(pkg|hallo)", true, true);
     assertWithMessage("Rule must not be null").that(rule).isNotNull();
     assertWithMessage("Invalid access result")
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheckTest.java
@@ -34,7 +34,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class RedundantImportCheckTest extends AbstractModuleTestSupport {
+final class RedundantImportCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -42,7 +42,7 @@ public class RedundantImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final RedundantImportCheck checkObj = new RedundantImportCheck();
     final int[] expected = {
       TokenTypes.IMPORT, TokenTypes.STATIC_IMPORT, TokenTypes.PACKAGE_DEF,
@@ -53,7 +53,7 @@ public class RedundantImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStateIsClearedOnBeginTree1() throws Exception {
+  void stateIsClearedOnBeginTree1() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RedundantImportCheck.class);
     final String inputWithWarnings = getPath("InputRedundantImportCheckClearState.java");
     final String inputWithoutWarnings = getPath("InputRedundantImportWithoutWarnings.java");
@@ -73,7 +73,7 @@ public class RedundantImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithChecker() throws Exception {
+  void withChecker() throws Exception {
     final String[] expected = {
       "9:1: "
           + getCheckMessage(
@@ -92,7 +92,7 @@ public class RedundantImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUnnamedPackage() throws Exception {
+  void unnamedPackage() throws Exception {
     final String[] expected = {
       "10:1: " + getCheckMessage(MSG_DUPLICATE, 9, "java.util.List"),
       "12:1: " + getCheckMessage(MSG_LANG, "java.lang.String"),
@@ -102,7 +102,7 @@ public class RedundantImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final RedundantImportCheck testCheckObject = new RedundantImportCheck();
     final int[] actual = testCheckObject.getAcceptableTokens();
     final int[] expected = {
@@ -113,7 +113,7 @@ public class RedundantImportCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBeginTreePackage() throws Exception {
+  void beginTreePackage() throws Exception {
     final String file1 = getPath("InputRedundantImportCheckClearState.java");
     final String file2 = getPath("InputRedundantImportWithoutPackage.java");
     final List<String> expectedFirstInput =
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/UnusedImportsCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/imports/UnusedImportsCheckTest.java
@@ -22,6 +22,7 @@ package com.puppycrawl.tools.checkstyle.checks.imports;
 import static com.google.common.truth.Truth.assertWithMessage;
 import static com.puppycrawl.tools.checkstyle.checks.imports.UnusedImportsCheck.MSG_KEY;
 
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
@@ -32,7 +33,7 @@ import java.util.Arrays;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class UnusedImportsCheckTest extends AbstractModuleTestSupport {
+final class UnusedImportsCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -40,7 +41,7 @@ public class UnusedImportsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testReferencedStateIsCleared() throws Exception {
+  void referencedStateIsCleared() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(UnusedImportsCheck.class);
     final String inputWithoutWarnings = getPath("InputUnusedImportsWithoutWarnings.java");
     final String inputWithWarnings = getPath("InputUnusedImportsCheckClearState.java");
@@ -72,7 +73,7 @@ public class UnusedImportsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithoutProcessJavadoc() throws Exception {
+  void withoutProcessJavadoc() throws Exception {
     final String[] expected = {
       "11:8: "
           + getCheckMessage(MSG_KEY, "com.google.errorprone.annotations." + "concurrent.GuardedBy"),
@@ -106,7 +107,7 @@ public class UnusedImportsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testProcessJavadoc() throws Exception {
+  void processJavadoc() throws Exception {
     final String[] expected = {
       "11:8: "
           + getCheckMessage(MSG_KEY, "com.google.errorprone.annotations." + "concurrent.GuardedBy"),
@@ -125,27 +126,27 @@ public class UnusedImportsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testProcessJavadocWithLinkTag() throws Exception {
+  void processJavadocWithLinkTag() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputUnusedImportsWithValueTag.java"), expected);
   }
 
   @Test
-  public void testProcessJavadocWithBlockTagContainingMethodParameters() throws Exception {
+  void processJavadocWithBlockTagContainingMethodParameters() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputUnusedImportsWithBlockMethodParameters.java"), expected);
   }
 
   @Test
-  public void testAnnotations() throws Exception {
+  void annotations() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getNonCompilablePath("InputUnusedImportsAnnotations.java"), expected);
   }
 
   @Test
-  public void testArrayRef() throws Exception {
+  void arrayRef() throws Exception {
     final String[] expected = {
       "13:8: " + getCheckMessage(MSG_KEY, "java.util.ArrayList"),
     };
@@ -153,20 +154,20 @@ public class UnusedImportsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBug() throws Exception {
+  void bug() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputUnusedImportsBug.java"), expected);
   }
 
   @Test
-  public void testNewlinesInsideTags() throws Exception {
+  void newlinesInsideTags() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputUnusedImportsWithNewlinesInsideTags.java"), expected);
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final UnusedImportsCheck testCheckObject = new UnusedImportsCheck();
     final int[] actual = testCheckObject.getRequiredTokens();
     final int[] expected = {
@@ -194,7 +195,7 @@ public class UnusedImportsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final UnusedImportsCheck testCheckObject = new UnusedImportsCheck();
     final int[] actual = testCheckObject.getAcceptableTokens();
     final int[] expected = {
@@ -222,7 +223,7 @@ public class UnusedImportsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFileInUnnamedPackage() throws Exception {
+  void fileInUnnamedPackage() throws Exception {
     final String[] expected = {
       "12:8: " + getCheckMessage(MSG_KEY, "java.util.Arrays"),
       "13:8: " + getCheckMessage(MSG_KEY, "java.lang.String"),
@@ -232,7 +233,7 @@ public class UnusedImportsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testImportsFromJavaLang() throws Exception {
+  void importsFromJavaLang() throws Exception {
     final String[] expected = {
       "10:8: " + getCheckMessage(MSG_KEY, "java.lang.String"),
       "11:8: " + getCheckMessage(MSG_KEY, "java.lang.Math"),
@@ -250,7 +251,7 @@ public class UnusedImportsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testImportsJavadocQualifiedName() throws Exception {
+  void importsJavadocQualifiedName() throws Exception {
     final String[] expected = {
       "11:8: " + getCheckMessage(MSG_KEY, "java.util.List"),
     };
@@ -258,7 +259,7 @@ public class UnusedImportsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSingleWordPackage() throws Exception {
+  void singleWordPackage() throws Exception {
     final String[] expected = {
       "10:8: " + getCheckMessage(MSG_KEY, "module"),
     };
@@ -267,7 +268,7 @@ public class UnusedImportsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRecordsAndCompactCtors() throws Exception {
+  void recordsAndCompactCtors() throws Exception {
     final String[] expected = {
       "19:8: " + getCheckMessage(MSG_KEY, "javax.swing.JToolBar"),
       "20:8: " + getCheckMessage(MSG_KEY, "javax.swing.JToggleButton"),
@@ -277,7 +278,7 @@ public class UnusedImportsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testShadowedImports() throws Exception {
+  void shadowedImports() throws Exception {
     final String[] expected = {
       "12:8: " + getCheckMessage(MSG_KEY, "java.util.Map"),
       "13:8: " + getCheckMessage(MSG_KEY, "java.util.Set"),
@@ -291,7 +292,7 @@ public class UnusedImportsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUnusedImports3() throws Exception {
+  void unusedImports3() throws Exception {
     final String[] expected = {
       "11:8: " + getCheckMessage(MSG_KEY, "java.awt.Rectangle"),
       "13:8: " + getCheckMessage(MSG_KEY, "java.awt.event.KeyEvent"),
@@ -300,14 +301,15 @@ public class UnusedImportsCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStateIsClearedOnBeginTreeCollect() throws Exception {
+  void stateIsClearedOnBeginTreeCollect() throws Exception {
     final String file1 = getNonCompilablePath("InputUnusedImportsRecordsAndCompactCtors.java");
     final String file2 = getNonCompilablePath("InputUnusedImportsSingleWordPackage.java");
     final List<String> expectedFirstInput =
-        List.of(
+        ImmutableList.of(
             "19:8: " + getCheckMessage(MSG_KEY, "javax.swing.JToolBar"),
             "20:8: " + getCheckMessage(MSG_KEY, "javax.swing.JToggleButton"));
-    final List<String> expectedSecondInput = List.of("10:8: " + getCheckMessage(MSG_KEY, "module"));
+    final List<String> expectedSecondInput =
+        ImmutableList.of("10:8: " + getCheckMessage(MSG_KEY, "module"));
     verifyWithInlineConfigParser(file1, file2, expectedFirstInput, expectedSecondInput);
   }
 }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/indentation/CommentsIndentationCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/indentation/CommentsIndentationCheckTest.java
@@ -29,7 +29,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
+final class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -37,7 +37,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommentIsAtTheEndOfBlockOne() throws Exception {
+  void commentIsAtTheEndOfBlockOne() throws Exception {
     final String[] expected = {
       "25:26: " + getCheckMessage(MSG_KEY_SINGLE, 24, 25, 8),
       "40:6: " + getCheckMessage(MSG_KEY_SINGLE, 42, 5, 4),
@@ -54,7 +54,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommentIsAtTheEndOfBlockTwo() throws Exception {
+  void commentIsAtTheEndOfBlockTwo() throws Exception {
     final String[] expected = {
       "22:30: " + getCheckMessage(MSG_KEY_SINGLE, 23, 29, 12),
       "45:27: " + getCheckMessage(MSG_KEY_SINGLE, 38, 26, 8),
@@ -68,7 +68,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommentIsAtTheEndOfBlockThree() throws Exception {
+  void commentIsAtTheEndOfBlockThree() throws Exception {
     final String[] expected = {
       "21:1: " + getCheckMessage(MSG_KEY_SINGLE, 20, 0, 8),
       "35:13: " + getCheckMessage(MSG_KEY_SINGLE, 32, 12, 8),
@@ -84,7 +84,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommentIsAtTheEndOfBlockFour() throws Exception {
+  void commentIsAtTheEndOfBlockFour() throws Exception {
     final String[] expected = {
       "22:10: " + getCheckMessage(MSG_KEY_SINGLE, 21, 9, 8),
       "28:1: " + getCheckMessage(MSG_KEY_SINGLE, 29, 0, 4),
@@ -100,7 +100,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommentIsAtTheEndOfBlockFive() throws Exception {
+  void commentIsAtTheEndOfBlockFive() throws Exception {
     final String[] expected = {
       "61:1: " + getCheckMessage(MSG_KEY_SINGLE, 59, 0, 8),
       "77:11: " + getCheckMessage(MSG_KEY_BLOCK, 73, 10, 8),
@@ -114,7 +114,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommentIsAtTheEndOfBlockSix() throws Exception {
+  void commentIsAtTheEndOfBlockSix() throws Exception {
     final String[] expected = {
       "26:11: " + getCheckMessage(MSG_KEY_SINGLE, 19, 10, 8),
       "33:1: " + getCheckMessage(MSG_KEY_SINGLE, 30, 0, 8),
@@ -132,7 +132,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommentIsInsideSwitchBlockOne() throws Exception {
+  void commentIsInsideSwitchBlockOne() throws Exception {
     final String[] expected = {
       "27:13: " + getCheckMessage(MSG_KEY_BLOCK, 28, 12, 16),
       "33:20: " + getCheckMessage(MSG_KEY_SINGLE, "32, 34", 19, "16, 12"),
@@ -148,7 +148,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommentIsInsideSwitchBlockTwo() throws Exception {
+  void commentIsInsideSwitchBlockTwo() throws Exception {
     final String[] expected = {
       "18:25: " + getCheckMessage(MSG_KEY_SINGLE, 19, 24, 20),
       "43:16: " + getCheckMessage(MSG_KEY_SINGLE, "42, 44", 15, "17, 12"),
@@ -161,7 +161,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommentIsInsideSwitchBlockThree() throws Exception {
+  void commentIsInsideSwitchBlockThree() throws Exception {
     final String[] expected = {
       "18:25: " + getCheckMessage(MSG_KEY_SINGLE, 19, 24, 20),
       "45:5: " + getCheckMessage(MSG_KEY_SINGLE, "44, 46", 4, "12, 12"),
@@ -175,7 +175,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommentIsInsideSwitchBlockFour() throws Exception {
+  void commentIsInsideSwitchBlockFour() throws Exception {
     final String[] expected = {
       "18:25: " + getCheckMessage(MSG_KEY_SINGLE, 19, 24, 20),
       "34:12: " + getCheckMessage(MSG_KEY_BLOCK, "33, 37", 11, "16, 12"),
@@ -187,7 +187,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommentIsInsideEmptyBlock() throws Exception {
+  void commentIsInsideEmptyBlock() throws Exception {
     final String[] expected = {
       "16:20: " + getCheckMessage(MSG_KEY_SINGLE, 19, 19, 31),
       "17:24: " + getCheckMessage(MSG_KEY_BLOCK, 19, 23, 31),
@@ -202,7 +202,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSurroundingCodeOne() throws Exception {
+  void surroundingCodeOne() throws Exception {
     final String[] expected = {
       "20:15: " + getCheckMessage(MSG_KEY_SINGLE, 21, 14, 12),
       "31:17: " + getCheckMessage(MSG_KEY_BLOCK, 32, 16, 12),
@@ -218,7 +218,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSurroundingCodeTwo() throws Exception {
+  void surroundingCodeTwo() throws Exception {
     final String[] expected = {
       "20:34: " + getCheckMessage(MSG_KEY_SINGLE, 21, 33, 8),
       "42:13: " + getCheckMessage(MSG_KEY_BLOCK, 43, 12, 8),
@@ -230,14 +230,14 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoNpeWhenBlockCommentEndsClassFile() throws Exception {
+  void noNpeWhenBlockCommentEndsClassFile() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     final String testInputFile = "InputCommentsIndentationNoNpe.java";
     verifyWithInlineConfigParser(getPath(testInputFile), expected);
   }
 
   @Test
-  public void testCheckOnlySingleLineComments() throws Exception {
+  void checkOnlySingleLineComments() throws Exception {
     final String[] expected = {
       "20:15: " + getCheckMessage(MSG_KEY_SINGLE, 21, 14, 12),
       "57:28: " + getCheckMessage(MSG_KEY_SINGLE, 60, 27, 36),
@@ -250,7 +250,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCheckOnlyBlockCommentsOne() throws Exception {
+  void checkOnlyBlockCommentsOne() throws Exception {
     final String[] expected = {
       "30:17: " + getCheckMessage(MSG_KEY_BLOCK, 31, 16, 12),
       "32:17: " + getCheckMessage(MSG_KEY_BLOCK, 34, 16, 12),
@@ -262,7 +262,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCheckOnlyBlockCommentsTwo() throws Exception {
+  void checkOnlyBlockCommentsTwo() throws Exception {
     final String[] expected = {
       "40:13: " + getCheckMessage(MSG_KEY_BLOCK, 41, 12, 8),
       "46:5: " + getCheckMessage(MSG_KEY_BLOCK, 47, 4, 8),
@@ -273,7 +273,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testVisitToken() {
+  void visitToken() {
     final CommentsIndentationCheck check = new CommentsIndentationCheck();
     final DetailAstImpl methodDef = new DetailAstImpl();
     methodDef.setType(TokenTypes.METHOD_DEF);
@@ -290,7 +290,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadoc() throws Exception {
+  void javadoc() throws Exception {
     final String[] expected = {
       "10:3: " + getCheckMessage(MSG_KEY_BLOCK, 13, 2, 0),
       "16:1: " + getCheckMessage(MSG_KEY_BLOCK, 17, 0, 4),
@@ -302,7 +302,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMultiblockStructuresOne() throws Exception {
+  void multiblockStructuresOne() throws Exception {
     final String[] expected = {
       "19:9: " + getCheckMessage(MSG_KEY_SINGLE, 18, 8, 12),
       "25:17: " + getCheckMessage(MSG_KEY_SINGLE, "24, 26", 16, "12, 8"),
@@ -325,7 +325,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMultiblockStructuresTwo() throws Exception {
+  void multiblockStructuresTwo() throws Exception {
     final String[] expected = {
       "20:9: " + getCheckMessage(MSG_KEY_SINGLE, 19, 8, 12),
       "26:17: " + getCheckMessage(MSG_KEY_SINGLE, "25, 27", 16, "12, 8"),
@@ -336,7 +336,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommentsAfterAnnotation() throws Exception {
+  void commentsAfterAnnotation() throws Exception {
     final String[] expected = {
       "21:5: " + getCheckMessage(MSG_KEY_SINGLE, 22, 4, 0),
       "25:9: " + getCheckMessage(MSG_KEY_SINGLE, 26, 8, 4),
@@ -349,7 +349,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommentsInSameMethodCallWithSameIndent() throws Exception {
+  void commentsInSameMethodCallWithSameIndent() throws Exception {
     final String[] expected = {
       "23:7: " + getCheckMessage(MSG_KEY_SINGLE, 24, 6, 4),
       "30:11: " + getCheckMessage(MSG_KEY_SINGLE, 31, 10, 4),
@@ -359,7 +359,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommentIndentationWithEmoji() throws Exception {
+  void commentIndentationWithEmoji() throws Exception {
     final String[] expected = {
       "14:9: " + getCheckMessage(MSG_KEY_SINGLE, 15, 8, 16),
       "25:13: " + getCheckMessage(MSG_KEY_SINGLE, 24, 12, 8),
@@ -376,7 +376,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommentsBlockCommentBeforePackage() throws Exception {
+  void commentsBlockCommentBeforePackage() throws Exception {
     final String[] expected = {
       "8:1: " + getCheckMessage(MSG_KEY_BLOCK, 11, 0, 1),
     };
@@ -385,7 +385,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommentsAfterRecordsAndCompactCtors() throws Exception {
+  void commentsAfterRecordsAndCompactCtors() throws Exception {
     final String[] expected = {
       "15:17: " + getCheckMessage(MSG_KEY_SINGLE, 16, 16, 20),
       "28:1: " + getCheckMessage(MSG_KEY_SINGLE, 29, 0, 4),
@@ -398,7 +398,7 @@ public class CommentsIndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommentsAtTheEndOfMethodCall() throws Exception {
+  void commentsAtTheEndOfMethodCall() throws Exception {
     final String[] expected = {
       "24:16: " + getCheckMessage(MSG_KEY_SINGLE, 20, 15, 8),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/indentation/IndentationCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/indentation/IndentationCheckTest.java
@@ -19,11 +19,13 @@
 
 package com.puppycrawl.tools.checkstyle.checks.indentation;
 
+import static com.google.common.base.Preconditions.checkState;
 import static com.google.common.truth.Truth.assertWithMessage;
 import static com.puppycrawl.tools.checkstyle.checks.indentation.IndentationCheck.MSG_CHILD_ERROR;
 import static com.puppycrawl.tools.checkstyle.checks.indentation.IndentationCheck.MSG_CHILD_ERROR_MULTI;
 import static com.puppycrawl.tools.checkstyle.checks.indentation.IndentationCheck.MSG_ERROR;
 import static com.puppycrawl.tools.checkstyle.checks.indentation.IndentationCheck.MSG_ERROR_MULTI;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.Checker;
@@ -34,7 +36,6 @@ import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.io.BufferedReader;
 import java.io.IOException;
-import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Paths;
 import java.util.ArrayList;
@@ -46,7 +47,7 @@ import java.util.regex.Pattern;
 import org.junit.jupiter.api.Test;
 
 /** Unit test for IndentationCheck. */
-public class IndentationCheckTest extends AbstractModuleTestSupport {
+final class IndentationCheckTest extends AbstractModuleTestSupport {
 
   private static final Pattern LINE_WITH_COMMENT_REGEX =
       Pattern.compile(
@@ -57,8 +58,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   private static IndentComment[] getLinesWithWarnAndCheckComments(
       String aFileName, final int tabWidth) throws IOException {
     final List<IndentComment> result = new ArrayList<>();
-    try (BufferedReader br =
-        Files.newBufferedReader(Paths.get(aFileName), StandardCharsets.UTF_8)) {
+    try (BufferedReader br = Files.newBufferedReader(Paths.get(aFileName), UTF_8)) {
       int lineNumber = 1;
       for (String line = br.readLine(); line != null; line = br.readLine()) {
         final Matcher match = LINE_WITH_COMMENT_REGEX.matcher(line);
@@ -66,26 +66,24 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
           final IndentComment warn = new IndentComment(match, lineNumber);
           final int actualIndent = getLineStart(line, tabWidth);
 
-          if (actualIndent != warn.getIndent()) {
-            throw new IllegalStateException(
-                String.format(
-                    Locale.ROOT,
-                    "File \"%1$s\" has incorrect indentation in comment. "
-                        + "Line %2$d: comment:%3$d, actual:%4$d.",
-                    aFileName,
-                    lineNumber,
-                    warn.getIndent(),
-                    actualIndent));
-          }
+          checkState(
+              actualIndent == warn.getIndent(),
+              String.format(
+                  Locale.ROOT,
+                  "File \"%1$s\" has incorrect indentation in comment. "
+                      + "Line %2$d: comment:%3$d, actual:%4$d.",
+                  aFileName,
+                  lineNumber,
+                  warn.getIndent(),
+                  actualIndent));
 
-          if (!isCommentConsistent(warn)) {
-            throw new IllegalStateException(
-                String.format(
-                    Locale.ROOT,
-                    "File \"%1$s\" has inconsistent comment on line %2$d",
-                    aFileName,
-                    lineNumber));
-          }
+          checkState(
+              isCommentConsistent(warn),
+              String.format(
+                  Locale.ROOT,
+                  "File \"%1$s\" has inconsistent comment on line %2$d",
+                  aFileName,
+                  lineNumber));
 
           if (warn.isWarning()) {
             result.add(warn);
@@ -169,7 +167,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final IndentationCheck checkObj = new IndentationCheck();
     final int[] requiredTokens = checkObj.getRequiredTokens();
     final HandlerFactory handlerFactory = new HandlerFactory();
@@ -182,7 +180,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final IndentationCheck checkObj = new IndentationCheck();
     final int[] acceptableTokens = checkObj.getAcceptableTokens();
     final HandlerFactory handlerFactory = new HandlerFactory();
@@ -195,7 +193,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testThrowsIndentProperty() {
+  void throwsIndentProperty() {
     final IndentationCheck indentationCheck = new IndentationCheck();
 
     indentationCheck.setThrowsIndent(1);
@@ -206,7 +204,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStrictCondition() throws Exception {
+  void strictCondition() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("arrayInitIndent", "4");
     checkConfig.addProperty("basicOffset", "4");
@@ -225,7 +223,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void forbidOldStyle() throws Exception {
+  void forbidOldStyle() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("arrayInitIndent", "4");
     checkConfig.addProperty("basicOffset", "4");
@@ -243,7 +241,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testZeroCaseLevel() throws Exception {
+  void zeroCaseLevel() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("arrayInitIndent", "4");
     checkConfig.addProperty("basicOffset", "4");
@@ -258,7 +256,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAndroidStyle() throws Exception {
+  void androidStyle() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("arrayInitIndent", "4");
     checkConfig.addProperty("basicOffset", "4");
@@ -283,7 +281,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMethodCallLineWrap() throws Exception {
+  void methodCallLineWrap() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -303,7 +301,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDifficultAnnotations() throws Exception {
+  void difficultAnnotations() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -329,7 +327,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationClosingParenthesisEndsInSameIndentationAsOpening() throws Exception {
+  void annotationClosingParenthesisEndsInSameIndentationAsOpening() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("basicOffset", "4");
@@ -352,7 +350,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnonClassesFromGuava() throws Exception {
+  void anonClassesFromGuava() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -368,7 +366,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotations() throws Exception {
+  void annotations() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -384,7 +382,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCorrectIfAndParameters() throws Exception {
+  void correctIfAndParameters() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -407,7 +405,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnonymousClasses() throws Exception {
+  void anonymousClasses() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -423,7 +421,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testArrays() throws Exception {
+  void arrays() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "2");
@@ -439,7 +437,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLabels() throws Exception {
+  void labels() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -455,7 +453,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClassesAndMethods() throws Exception {
+  void classesAndMethods() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -471,7 +469,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCtorCall() throws Exception {
+  void ctorCall() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("basicOffset", "2");
@@ -504,7 +502,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMembers() throws Exception {
+  void members() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -524,7 +522,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationArrayInit() throws Exception {
+  void annotationArrayInit() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "6");
@@ -560,7 +558,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationArrayInitTwo() throws Exception {
+  void annotationArrayInitTwo() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "0");
@@ -588,7 +586,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationArrayInitWithEmoji() throws Exception {
+  void annotationArrayInitWithEmoji() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "0");
@@ -626,7 +624,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOddAnnotations() throws Exception {
+  void oddAnnotations() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "3");
@@ -648,7 +646,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationOddStyles() throws Exception {
+  void annotationOddStyles() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("tabWidth", "8");
@@ -661,7 +659,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testZeroAnnotationArrayInit() throws Exception {
+  void zeroAnnotationArrayInit() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "0");
@@ -683,7 +681,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationArrayInitGoodCase() throws Exception {
+  void annotationArrayInitGoodCase() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -700,7 +698,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationArrayInitGoodCaseTwo() throws Exception {
+  void annotationArrayInitGoodCaseTwo() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -717,7 +715,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidLabel() throws Exception {
+  void invalidLabel() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -740,7 +738,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidLabelWithWhileLoop() throws Exception {
+  void invalidLabelWithWhileLoop() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -760,7 +758,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidLabel() throws Exception {
+  void validLabel() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -776,7 +774,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidIfWithChecker() throws Exception {
+  void validIfWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -795,7 +793,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidDotWithChecker() throws Exception {
+  void validDotWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -812,7 +810,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidMethodWithChecker() throws Exception {
+  void validMethodWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -832,7 +830,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidMethodWithChecker() throws Exception {
+  void invalidMethodWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -885,7 +883,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAlternativeGoogleStyleSwitchCaseAndEnums() throws Exception {
+  void alternativeGoogleStyleSwitchCaseAndEnums() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -908,7 +906,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidSwitchWithChecker() throws Exception {
+  void invalidSwitchWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -955,7 +953,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIfElseWithNoCurly() throws Exception {
+  void ifElseWithNoCurly() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -979,7 +977,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWhileWithNoCurly() throws Exception {
+  void whileWithNoCurly() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1002,7 +1000,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testForWithNoCurly() throws Exception {
+  void forWithNoCurly() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1026,7 +1024,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDoWhileWithoutCurly() throws Exception {
+  void doWhileWithoutCurly() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1047,7 +1045,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidSwitchWithChecker() throws Exception {
+  void validSwitchWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1064,7 +1062,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNewKeyword() throws Exception {
+  void newKeyword() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("basicOffset", "4");
@@ -1077,7 +1075,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNewKeyword2() throws Exception {
+  void newKeyword2() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("basicOffset", "4");
@@ -1090,7 +1088,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidNewKeywordWithForceStrictCondition() throws Exception {
+  void validNewKeywordWithForceStrictCondition() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("basicOffset", "4");
@@ -1103,7 +1101,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidNewKeywordWithForceStrictCondition() throws Exception {
+  void invalidNewKeywordWithForceStrictCondition() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("basicOffset", "4");
@@ -1131,7 +1129,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidArrayInitDefaultIndentWithChecker() throws Exception {
+  void validArrayInitDefaultIndentWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1148,7 +1146,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidArrayInitWithChecker() throws Exception {
+  void validArrayInitWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "8");
@@ -1165,7 +1163,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidArrayInitTwoDimensional() throws Exception {
+  void validArrayInitTwoDimensional() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "2");
@@ -1182,7 +1180,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidArrayInitTwoDimensional() throws Exception {
+  void invalidArrayInitTwoDimensional() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "2");
@@ -1212,7 +1210,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidArrayInit() throws Exception {
+  void validArrayInit() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "2");
@@ -1229,7 +1227,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidArrayInitWithChecker() throws Exception {
+  void invalidArrayInitWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1291,7 +1289,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testArrayInitWithEmoji() throws Exception {
+  void arrayInitWithEmoji() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "2");
@@ -1315,7 +1313,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testChainedMethodCalling() throws Exception {
+  void chainedMethodCalling() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "2");
@@ -1337,7 +1335,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidArrayInitWithTrueStrictCondition() throws Exception {
+  void invalidArrayInitWithTrueStrictCondition() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1399,7 +1397,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidTryWithChecker() throws Exception {
+  void validTryWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1416,7 +1414,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidTryWithChecker() throws Exception {
+  void invalidTryWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1462,7 +1460,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidClassDefWithChecker() throws Exception {
+  void invalidClassDefWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1514,7 +1512,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidBlockWithChecker() throws Exception {
+  void invalidBlockWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1578,7 +1576,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidIfWithChecker() throws Exception {
+  void invalidIfWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1670,7 +1668,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidWhileWithChecker() throws Exception {
+  void invalidWhileWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1716,7 +1714,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidInvalidAnonymousClass() throws Exception {
+  void invalidInvalidAnonymousClass() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1733,7 +1731,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidForWithChecker() throws Exception {
+  void invalidForWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1781,7 +1779,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidForWithChecker() throws Exception {
+  void validForWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1798,7 +1796,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidDoWhileWithChecker() throws Exception {
+  void validDoWhileWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1815,7 +1813,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidDoWhileWithChecker() throws Exception {
+  void invalidDoWhileWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1850,7 +1848,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidBlockWithChecker() throws Exception {
+  void validBlockWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1867,7 +1865,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidWhileWithChecker() throws Exception {
+  void validWhileWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1884,7 +1882,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidClassDefWithChecker() throws Exception {
+  void validClassDefWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1904,7 +1902,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidInterfaceDefWithChecker() throws Exception {
+  void validInterfaceDefWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1921,7 +1919,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidCommaWithChecker() throws Exception {
+  void validCommaWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1938,7 +1936,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTabs() throws Exception {
+  void tabs() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1956,7 +1954,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIndentationLevel() throws Exception {
+  void indentationLevel() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1974,7 +1972,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testThrowsIndentationLevel() throws Exception {
+  void throwsIndentationLevel() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -1990,7 +1988,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testThrowsIndentationLevel2() throws Exception {
+  void throwsIndentationLevel2() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("basicOffset", "1");
@@ -2017,7 +2015,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCaseLevel() throws Exception {
+  void caseLevel() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -2035,7 +2033,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBraceAdjustment() throws Exception {
+  void braceAdjustment() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -2057,7 +2055,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidAssignWithChecker() throws Exception {
+  void invalidAssignWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -2078,7 +2076,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidImportIndent() throws Exception {
+  void invalidImportIndent() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("basicOffset", "8");
     checkConfig.addProperty("tabWidth", "4");
@@ -2090,7 +2088,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValidAssignWithChecker() throws Exception {
+  void validAssignWithChecker() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -2106,7 +2104,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test15Extensions() throws Exception {
+  void test15Extensions() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -2122,7 +2120,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTryResources() throws Exception {
+  void tryResources() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -2138,7 +2136,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSwitchCustom() throws Exception {
+  void switchCustom() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -2154,7 +2152,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSynchronizedStatement() throws Exception {
+  void synchronizedStatement() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("arrayInitIndent", "4");
     checkConfig.addProperty("basicOffset", "4");
@@ -2172,7 +2170,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSynchronizedMethod() throws Exception {
+  void synchronizedMethod() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("arrayInitIndent", "4");
     checkConfig.addProperty("basicOffset", "4");
@@ -2187,7 +2185,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnonymousClassInMethod() throws Exception {
+  void anonymousClassInMethod() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "8");
     checkConfig.addProperty("basicOffset", "2");
@@ -2208,7 +2206,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnonymousClassInMethodWithCurlyOnNewLine() throws Exception {
+  void anonymousClassInMethodWithCurlyOnNewLine() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     checkConfig.addProperty("basicOffset", "4");
@@ -2233,7 +2231,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationDefinition() throws Exception {
+  void annotationDefinition() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -2241,7 +2239,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackageDeclaration() throws Exception {
+  void packageDeclaration() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     final String[] expected = {
@@ -2251,7 +2249,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackageDeclaration2() throws Exception {
+  void packageDeclaration2() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     final String[] expected = {
@@ -2261,7 +2259,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackageDeclaration3() throws Exception {
+  void packageDeclaration3() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -2269,7 +2267,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackageDeclaration4() throws Exception {
+  void packageDeclaration4() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     final String[] expected = {
@@ -2280,7 +2278,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLambda1() throws Exception {
+  void lambda1() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "2");
     checkConfig.addProperty("basicOffset", "2");
@@ -2300,7 +2298,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLambda2() throws Exception {
+  void lambda2() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     checkConfig.addProperty("basicOffset", "4");
@@ -2310,7 +2308,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLambda3() throws Exception {
+  void lambda3() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     checkConfig.addProperty("basicOffset", "4");
@@ -2327,7 +2325,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLambda4() throws Exception {
+  void lambda4() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     checkConfig.addProperty("basicOffset", "4");
@@ -2337,7 +2335,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLambda5() throws Exception {
+  void lambda5() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "3");
     checkConfig.addProperty("basicOffset", "3");
@@ -2348,7 +2346,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLambdaFalseForceStrictCondition() throws Exception {
+  void lambdaFalseForceStrictCondition() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     checkConfig.addProperty("basicOffset", "4");
@@ -2367,7 +2365,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLambdaTrueForceStrictCondition() throws Exception {
+  void lambdaTrueForceStrictCondition() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     checkConfig.addProperty("basicOffset", "4");
@@ -2396,7 +2394,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLambdaOddConditions() throws Exception {
+  void lambdaOddConditions() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     checkConfig.addProperty("basicOffset", "3");
@@ -2409,7 +2407,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSeparatedStatements() throws Exception {
+  void separatedStatements() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     final String fileName = getPath("InputIndentationSeparatedStatements.java");
@@ -2418,7 +2416,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSeparatedLineWithJustSpaces() throws Exception {
+  void separatedLineWithJustSpaces() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     final String fileName = getPath("InputIndentationSeparatedStatementWithSpaces.java");
@@ -2427,7 +2425,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTwoStatementsPerLine() throws Exception {
+  void twoStatementsPerLine() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     checkConfig.addProperty("basicOffset", "4");
@@ -2437,7 +2435,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMethodChaining() throws Exception {
+  void methodChaining() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     checkConfig.addProperty("basicOffset", "4");
@@ -2447,7 +2445,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMultipleAnnotationsWithWrappedLines() throws Exception {
+  void multipleAnnotationsWithWrappedLines() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     checkConfig.addProperty("basicOffset", "4");
@@ -2459,7 +2457,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMethodPrecedeByAnnotationsWithParameterOnSeparateLine() throws Exception {
+  void methodPrecedeByAnnotationsWithParameterOnSeparateLine() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     checkConfig.addProperty("basicOffset", "2");
@@ -2475,7 +2473,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationIncorrect() throws Exception {
+  void annotationIncorrect() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     checkConfig.addProperty("basicOffset", "4");
@@ -2491,7 +2489,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInputAnnotationScopeIndentationCheck() throws Exception {
+  void inputAnnotationScopeIndentationCheck() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     checkConfig.addProperty("basicOffset", "4");
@@ -2505,7 +2503,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInputAnnotationDefIndentationCheck() throws Exception {
+  void inputAnnotationDefIndentationCheck() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     checkConfig.addProperty("arrayInitIndent", "4");
@@ -2550,7 +2548,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTryResourcesStrict() throws Exception {
+  void tryResourcesStrict() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     checkConfig.addProperty("forceStrictCondition", "true");
@@ -2585,7 +2583,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTryResourcesNotStrict() throws Exception {
+  void tryResourcesNotStrict() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     checkConfig.addProperty("braceAdjustment", "0");
@@ -2624,7 +2622,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
    * @see IndentComment#getExpectedMessagePostfix(String)
    */
   @Test
-  public void testArgumentOrderOfErrorMessages() {
+  void argumentOrderOfErrorMessages() {
     final Object[] arguments = {"##0##", "##1##", "##2##"};
     final String[] messages = {
       getCheckMessage(MSG_ERROR, arguments),
@@ -2651,7 +2649,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyArray() throws Exception {
+  void emptyArray() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -2659,7 +2657,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNewHandler() throws Exception {
+  void newHandler() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     final String[] expected = {
@@ -2673,7 +2671,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTryHandler() throws Exception {
+  void tryHandler() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     checkConfig.addProperty("braceAdjustment", "0");
@@ -2684,7 +2682,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTryHandler2() throws Exception {
+  void tryHandler2() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     checkConfig.addProperty("braceAdjustment", "0");
@@ -2698,7 +2696,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testChainedMethodWithBracketOnNewLine() throws Exception {
+  void chainedMethodWithBracketOnNewLine() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
 
     checkConfig.addProperty("arrayInitIndent", "2");
@@ -2722,7 +2720,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIndentationSwitchExpression() throws Exception {
+  void indentationSwitchExpression() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     final String[] expected = {
@@ -2746,7 +2744,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIndentationYieldStatement() throws Exception {
+  void indentationYieldStatement() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     final String[] expected = {
@@ -2762,7 +2760,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIndentationSwitchExpressionCorrect() throws Exception {
+  void indentationSwitchExpressionCorrect() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -2773,7 +2771,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIndentationSwitchExpressionDeclaration() throws Exception {
+  void indentationSwitchExpressionDeclaration() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     checkConfig.addProperty("caseIndent", "4");
@@ -2795,7 +2793,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIndentationSwitchExpressionDeclarationLeftCurlyNewLine() throws Exception {
+  void indentationSwitchExpressionDeclarationLeftCurlyNewLine() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     final String[] expected = {
@@ -2811,7 +2809,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIndentationRecords() throws Exception {
+  void indentationRecords() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     checkConfig.addProperty("basicOffset", "4");
@@ -2828,7 +2826,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIndentationRecordsAndCompactCtors() throws Exception {
+  void indentationRecordsAndCompactCtors() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     final String[] expected = {
@@ -2845,7 +2843,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIndentationSwitchExpressionNewLine() throws Exception {
+  void indentationSwitchExpressionNewLine() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     final String[] expected = {
@@ -2860,7 +2858,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIndentationMethodParenthesisOnNewLine() throws Exception {
+  void indentationMethodParenthesisOnNewLine() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     final String[] expected = {
@@ -2872,7 +2870,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIndentationMethodParenthesisOnNewLine1() throws Exception {
+  void indentationMethodParenthesisOnNewLine1() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     final String[] expected = {
@@ -2885,7 +2883,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIndentationLineWrappedRecordDeclaration() throws Exception {
+  void indentationLineWrappedRecordDeclaration() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     checkConfig.addProperty("basicOffset", "4");
@@ -2924,7 +2922,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIndentationAnnotationFieldDefinition() throws Exception {
+  void indentationAnnotationFieldDefinition() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
     checkConfig.addProperty("basicOffset", "4");
@@ -2944,7 +2942,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIndentationLongConcatenatedString() throws Exception {
+  void indentationLongConcatenatedString() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
 
@@ -2954,7 +2952,7 @@ public class IndentationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIndentationLineBreakVariableDeclaration() throws Exception {
+  void indentationLineBreakVariableDeclaration() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(IndentationCheck.class);
     checkConfig.addProperty("tabWidth", "4");
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/AbstractJavadocCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/AbstractJavadocCheckTest.java
@@ -26,7 +26,7 @@ import static com.puppycrawl.tools.checkstyle.checks.javadoc.AbstractJavadocChec
 import static com.puppycrawl.tools.checkstyle.checks.javadoc.AbstractJavadocCheck.MSG_JAVADOC_WRONG_SINGLETON_TAG;
 import static com.puppycrawl.tools.checkstyle.checks.javadoc.JavadocTypeCheck.MSG_TAG_FORMAT;
 import static com.puppycrawl.tools.checkstyle.checks.javadoc.SummaryJavadocCheck.MSG_SUMMARY_FIRST_SENTENCE;
-import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.assertj.core.api.Assertions.assertThatCode;
 
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
@@ -44,7 +44,7 @@ import org.junit.jupiter.api.extension.ExtendWith;
 import org.junit.jupiter.api.io.TempDir;
 
 @ExtendWith(SystemErrGuard.class)
-public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
+final class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
 
   @TempDir public File temporaryFolder;
 
@@ -63,12 +63,12 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
    * @param systemErr wrapper for {@code System.err}
    */
   @BeforeEach
-  public void setUp(@SysErr Capturable systemErr) {
+  void setUp(@SysErr Capturable systemErr) {
     systemErr.captureMuted();
   }
 
   @Test
-  public void testJavadocTagsWithoutArgs() throws Exception {
+  void javadocTagsWithoutArgs() throws Exception {
     final String[] expected = {
       "16: "
           + getCheckMessage(
@@ -109,7 +109,7 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNumberFormatException() throws Exception {
+  void numberFormatException() throws Exception {
     final String[] expected = {
       "8: "
           + getCheckMessage(
@@ -123,13 +123,13 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCustomTag() throws Exception {
+  void customTag() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAbstractJavadocCustomTag.java"), expected);
   }
 
   @Test
-  public void testParsingErrors(@SysErr Capturable systemErr) throws Exception {
+  void parsingErrors(@SysErr Capturable systemErr) throws Exception {
     final String[] expected = {
       "9: " + getCheckMessage(MSG_JAVADOC_MISSED_HTML_CLOSE, 4, "unclosedTag"),
       "16: " + getCheckMessage(MSG_JAVADOC_WRONG_SINGLETON_TAG, 35, "img"),
@@ -139,19 +139,19 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithMultipleChecksOne() throws Exception {
+  void withMultipleChecksOne() throws Exception {
     verifyWithInlineConfigParser(
         getPath("InputAbstractJavadocCorrectParagraphOne.java"), CommonUtil.EMPTY_STRING_ARRAY);
   }
 
   @Test
-  public void testWithMultipleChecksTwo() throws Exception {
+  void withMultipleChecksTwo() throws Exception {
     verifyWithInlineConfigParser(
         getPath("InputAbstractJavadocCorrectParagraphTwo.java"), CommonUtil.EMPTY_STRING_ARRAY);
   }
 
   @Test
-  public void testAntlrError(@SysErr Capturable systemErr) throws Exception {
+  void antlrError(@SysErr Capturable systemErr) throws Exception {
     final String[] expected = {
       "9: "
           + getCheckMessage(
@@ -163,8 +163,8 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCheckReuseAfterParseErrorWithFollowingAntlrErrorInTwoFiles(
-      @SysErr Capturable systemErr) throws Exception {
+  void checkReuseAfterParseErrorWithFollowingAntlrErrorInTwoFiles(@SysErr Capturable systemErr)
+      throws Exception {
     final String[] expectedMessagesForFile1 = {
       "9: " + getCheckMessage(MSG_JAVADOC_MISSED_HTML_CLOSE, 4, "unclosedTag"),
       "16: " + getCheckMessage(MSG_JAVADOC_WRONG_SINGLETON_TAG, 35, "img"),
@@ -184,7 +184,7 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCheckReuseAfterParseErrorWithFollowingAntlrErrorInSingleFile() throws Exception {
+  void checkReuseAfterParseErrorWithFollowingAntlrErrorInSingleFile() throws Exception {
     final String[] expected = {
       "9: " + getCheckMessage(MSG_JAVADOC_MISSED_HTML_CLOSE, 4, "unclosedTag"),
       "16: "
@@ -196,7 +196,7 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCache() throws Exception {
+  void cache() throws Exception {
     final String[] expected = {
       "12: " + getCheckMessage(SummaryJavadocCheck.class, MSG_SUMMARY_FIRST_SENTENCE),
     };
@@ -207,7 +207,7 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPositionOne() throws Exception {
+  void positionOne() throws Exception {
     JavadocCatchCheck.clearCounter();
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAbstractJavadocPositionOne.java"), expected);
@@ -219,7 +219,7 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPositionTwo() throws Exception {
+  void positionTwo() throws Exception {
     JavadocCatchCheck.clearCounter();
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAbstractJavadocPositionTwo.java"), expected);
@@ -231,7 +231,7 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPositionThree() throws Exception {
+  void positionThree() throws Exception {
     JavadocCatchCheck.clearCounter();
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAbstractJavadocPositionThree.java"), expected);
@@ -243,7 +243,7 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPositionWithSinglelineCommentsOne() throws Exception {
+  void positionWithSinglelineCommentsOne() throws Exception {
     JavadocCatchCheck.clearCounter();
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
@@ -256,7 +256,7 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPositionWithSinglelineCommentsTwo() throws Exception {
+  void positionWithSinglelineCommentsTwo() throws Exception {
     JavadocCatchCheck.clearCounter();
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
@@ -269,7 +269,7 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPositionWithSinglelineCommentsThree() throws Exception {
+  void positionWithSinglelineCommentsThree() throws Exception {
     JavadocCatchCheck.clearCounter();
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
@@ -282,7 +282,7 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPositionOnlyComments() throws Exception {
+  void positionOnlyComments() throws Exception {
     JavadocCatchCheck.clearCounter();
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
@@ -293,7 +293,7 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokens() {
+  void tokens() {
     final int[] defaultJavadocTokens = {JavadocTokenTypes.JAVADOC};
     final AbstractJavadocCheck check =
         new AbstractJavadocCheck() {
@@ -329,7 +329,7 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokensFail() {
+  void tokensFail() {
     final int[] defaultJavadocTokens = {
       JavadocTokenTypes.JAVADOC,
       JavadocTokenTypes.AREA_HTML_TAG_NAME,
@@ -351,11 +351,11 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
           }
         };
     check.setJavadocTokens("RETURN_LITERAL");
-    assertDoesNotThrow(check::init);
+    assertThatCode(check::init).doesNotThrowAnyException();
   }
 
   @Test
-  public void testAcceptableTokensFail() throws Exception {
+  void acceptableTokensFail() throws Exception {
     final String path = getPath("InputAbstractJavadocTokensFail.java");
     try {
       final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -374,13 +374,13 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAcceptableTokensPass() throws Exception {
+  void acceptableTokensPass() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAbstractJavadocTokensPass.java"), expected);
   }
 
   @Test
-  public void testRequiredTokenIsNotInDefaultTokens() throws Exception {
+  void requiredTokenIsNotInDefaultTokens() throws Exception {
     final DefaultConfiguration checkConfig =
         createModuleConfig(RequiredTokenIsNotInDefaultsJavadocCheck.class);
     final String pathToEmptyFile = File.createTempFile("empty", ".java", temporaryFolder).getPath();
@@ -402,7 +402,7 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testVisitLeaveTokenOne() throws Exception {
+  void visitLeaveTokenOne() throws Exception {
     JavadocVisitLeaveCheck.clearCounter();
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAbstractJavadocLeaveTokenOne.java"), expected);
@@ -415,7 +415,7 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testVisitLeaveTokenTwo() throws Exception {
+  void visitLeaveTokenTwo() throws Exception {
     JavadocVisitLeaveCheck.clearCounter();
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAbstractJavadocLeaveTokenTwo.java"), expected);
@@ -428,7 +428,7 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testVisitLeaveTokenThree() throws Exception {
+  void visitLeaveTokenThree() throws Exception {
     JavadocVisitLeaveCheck.clearCounter();
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAbstractJavadocLeaveTokenThree.java"), expected);
@@ -441,7 +441,7 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoWsBeforeDescriptionInJavadocTags() throws Exception {
+  void noWsBeforeDescriptionInJavadocTags() throws Exception {
     final String[] expected = {
       "18: "
           + getCheckMessage(
@@ -491,7 +491,7 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWrongSingletonTagInJavadoc() throws Exception {
+  void wrongSingletonTagInJavadoc() throws Exception {
     final String[] expected = {
       "10: " + getCheckMessage(MSG_JAVADOC_WRONG_SINGLETON_TAG, 9, "embed"),
       "17: " + getCheckMessage(MSG_JAVADOC_WRONG_SINGLETON_TAG, 9, "keygen"),
@@ -504,7 +504,7 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonTightHtmlTagIntolerantCheckOne() throws Exception {
+  void nonTightHtmlTagIntolerantCheckOne() throws Exception {
     final String[] expected = {
       "12: " + getCheckMessage(MSG_UNCLOSED_HTML_TAG, "p"),
       "19: " + getCheckMessage(MSG_UNCLOSED_HTML_TAG, "p"),
@@ -518,7 +518,7 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonTightHtmlTagIntolerantCheckTwo() throws Exception {
+  void nonTightHtmlTagIntolerantCheckTwo() throws Exception {
     final String[] expected = {
       "12: " + getCheckMessage(MSG_UNCLOSED_HTML_TAG, "p"),
       "19: " + getCheckMessage(MSG_UNCLOSED_HTML_TAG, "p"),
@@ -530,21 +530,21 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonTightHtmlTagIntolerantCheckReportingNoViolationOne() throws Exception {
+  void nonTightHtmlTagIntolerantCheckReportingNoViolationOne() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputAbstractJavadocNonTightHtmlTagsNoViolationOne.java"), expected);
   }
 
   @Test
-  public void testNonTightHtmlTagIntolerantCheckReportingNoViolationTwo() throws Exception {
+  void nonTightHtmlTagIntolerantCheckReportingNoViolationTwo() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputAbstractJavadocNonTightHtmlTagsNoViolationTwo.java"), expected);
   }
 
   @Test
-  public void testNonTightHtmlTagIntolerantCheckVisitCountOne() throws Exception {
+  void nonTightHtmlTagIntolerantCheckVisitCountOne() throws Exception {
     final String[] expected = {
       "13: " + getCheckMessage(MSG_UNCLOSED_HTML_TAG, "p"),
       "20: " + getCheckMessage(MSG_UNCLOSED_HTML_TAG, "p"),
@@ -560,7 +560,7 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonTightHtmlTagIntolerantCheckVisitCountTwo() throws Exception {
+  void nonTightHtmlTagIntolerantCheckVisitCountTwo() throws Exception {
     final String[] expected = {
       "13: " + getCheckMessage(MSG_UNCLOSED_HTML_TAG, "p"),
       "20: " + getCheckMessage(MSG_UNCLOSED_HTML_TAG, "p"),
@@ -577,7 +577,7 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testVisitCountForCheckAcceptingJavadocWithNonTightHtml() throws Exception {
+  void visitCountForCheckAcceptingJavadocWithNonTightHtml() throws Exception {
     final String[] expected = {
       "11:4: " + getCheckMessage(NonTightHtmlTagCheck.MSG_KEY, "BODY_TAG_START"),
       "12:4: " + getCheckMessage(NonTightHtmlTagCheck.MSG_KEY, "P_TAG_START"),
@@ -619,7 +619,7 @@ public class AbstractJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testVisitCountForCheckAcceptingJavadocWithNonTightHtml3() throws Exception {
+  void visitCountForCheckAcceptingJavadocWithNonTightHtml3() throws Exception {
     final String[] expected = {
       "29:8: " + getCheckMessage(NonTightHtmlTagCheck.MSG_KEY, "P_TAG_START"),
       "36: " + getCheckMessage(MSG_UNCLOSED_HTML_TAG, "p"),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/AtclauseOrderCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/AtclauseOrderCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class AtclauseOrderCheckTest extends AbstractModuleTestSupport {
+final class AtclauseOrderCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class AtclauseOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final AtclauseOrderCheck checkObj = new AtclauseOrderCheck();
     final int[] expected = {TokenTypes.BLOCK_COMMENT_BEGIN};
     assertWithMessage("Default acceptable tokens are invalid")
@@ -44,7 +44,7 @@ public class AtclauseOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final AtclauseOrderCheck checkObj = new AtclauseOrderCheck();
     final int[] expected = {TokenTypes.BLOCK_COMMENT_BEGIN};
     assertWithMessage("Default acceptable tokens are invalid")
@@ -53,35 +53,35 @@ public class AtclauseOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCorrect1() throws Exception {
+  void correct1() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputAtclauseOrderCorrect1.java"), expected);
   }
 
   @Test
-  public void testCorrect2() throws Exception {
+  void correct2() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputAtclauseOrderCorrect2.java"), expected);
   }
 
   @Test
-  public void testCorrect3() throws Exception {
+  void correct3() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputAtclauseOrderCorrect3.java"), expected);
   }
 
   @Test
-  public void testCorrect4() throws Exception {
+  void correct4() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputAtclauseOrderCorrect4.java"), expected);
   }
 
   @Test
-  public void testIncorrect1() throws Exception {
+  void incorrect1() throws Exception {
     final String tagOrder =
         "[@author, @version, @param, @return, @throws, @exception, @see,"
             + " @since, @serial, @serialField, @serialData, @deprecated]";
@@ -105,7 +105,7 @@ public class AtclauseOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIncorrect2() throws Exception {
+  void incorrect2() throws Exception {
     final String tagOrder =
         "[@author, @version, @param, @return, @throws, @exception, @see,"
             + " @since, @serial, @serialField, @serialData, @deprecated]";
@@ -129,7 +129,7 @@ public class AtclauseOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIncorrect3() throws Exception {
+  void incorrect3() throws Exception {
     final String tagOrder =
         "[@author, @version, @param, @return, @throws, @exception, @see,"
             + " @since, @serial, @serialField, @serialData, @deprecated]";
@@ -147,7 +147,7 @@ public class AtclauseOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIncorrect4() throws Exception {
+  void incorrect4() throws Exception {
     final String tagOrder =
         "[@author, @version, @param, @return, @throws, @exception, @see,"
             + " @since, @serial, @serialField, @serialData, @deprecated]";
@@ -172,14 +172,14 @@ public class AtclauseOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIncorrectCustom1() throws Exception {
+  void incorrectCustom1() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputAtclauseOrderIncorrectCustom1.java"), expected);
   }
 
   @Test
-  public void testIncorrectCustom2() throws Exception {
+  void incorrectCustom2() throws Exception {
     final String tagOrder =
         "[@since, @version, @param, @return, @throws, @exception,"
             + " @deprecated, @see, @serial, @serialField, @serialData, @author]";
@@ -190,7 +190,7 @@ public class AtclauseOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIncorrectCustom3() throws Exception {
+  void incorrectCustom3() throws Exception {
     final String tagOrder =
         "[@since, @version, @param, @return, @throws, @exception,"
             + " @deprecated, @see, @serial, @serialField, @serialData, @author]";
@@ -201,7 +201,7 @@ public class AtclauseOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIncorrectCustom4() throws Exception {
+  void incorrectCustom4() throws Exception {
     final String tagOrder =
         "[@since, @version, @param, @return, @throws, @exception,"
             + " @deprecated, @see, @serial, @serialField, @serialData, @author]";
@@ -212,14 +212,14 @@ public class AtclauseOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackageInfo() throws Exception {
+  void packageInfo() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("package-info.java"), expected);
   }
 
   @Test
-  public void testAtclauseOrderRecords() throws Exception {
+  void atclauseOrderRecords() throws Exception {
     final String tagOrder =
         "[@author, @version, @param, @return, @throws, @exception,"
             + " @see, @since, @serial, @serialField, @serialData, @deprecated]";
@@ -238,7 +238,7 @@ public class AtclauseOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMethodReturningArrayType() throws Exception {
+  void methodReturningArrayType() throws Exception {
     final String tagOrder =
         "[@author, @version, @param, @return, @throws, @exception, @see,"
             + " @since, @serial, @serialField, @serialData, @deprecated]";
@@ -252,7 +252,7 @@ public class AtclauseOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAtclauseOrderLotsOfRecords1() throws Exception {
+  void atclauseOrderLotsOfRecords1() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -260,7 +260,7 @@ public class AtclauseOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAtclauseOrderLotsOfRecords2() throws Exception {
+  void atclauseOrderLotsOfRecords2() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -268,7 +268,7 @@ public class AtclauseOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAtclauseOrderLotsOfRecords3() throws Exception {
+  void atclauseOrderLotsOfRecords3() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -276,7 +276,7 @@ public class AtclauseOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAtclauseOrderLotsOfRecords4() throws Exception {
+  void atclauseOrderLotsOfRecords4() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -284,7 +284,7 @@ public class AtclauseOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAtclause() throws Exception {
+  void atclause() throws Exception {
     final String tagOrder =
         "[@author, @version, @param, @return, @throws, @exception, @see,"
             + " @since, @serial, @serialField, @serialData, @deprecated]";
@@ -317,7 +317,7 @@ public class AtclauseOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNewArrayDeclaratorStructure() throws Exception {
+  void newArrayDeclaratorStructure() throws Exception {
     final String tagOrder =
         "[@author, @version, @param, @return, @throws, @exception, @see,"
             + " @since, @serial, @serialField, @serialData, @deprecated]";
@@ -335,7 +335,7 @@ public class AtclauseOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTrim() throws Exception {
+  void trim() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAtclauseOrder1.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/InvalidJavadocPositionCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/InvalidJavadocPositionCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class InvalidJavadocPositionCheckTest extends AbstractModuleTestSupport {
+final class InvalidJavadocPositionCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class InvalidJavadocPositionCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final int[] expected = {
       TokenTypes.BLOCK_COMMENT_BEGIN,
     };
@@ -45,7 +45,7 @@ public class InvalidJavadocPositionCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final int[] expected = {
       TokenTypes.BLOCK_COMMENT_BEGIN,
     };
@@ -56,7 +56,7 @@ public class InvalidJavadocPositionCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "7:9: " + getCheckMessage(MSG_KEY),
       "10:1: " + getCheckMessage(MSG_KEY),
@@ -89,7 +89,7 @@ public class InvalidJavadocPositionCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackageInfo() throws Exception {
+  void packageInfo() throws Exception {
     final String[] expected = {
       "7:1: " + getCheckMessage(MSG_KEY),
     };
@@ -97,7 +97,7 @@ public class InvalidJavadocPositionCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackageInfoComment() throws Exception {
+  void packageInfoComment() throws Exception {
     final String[] expected = {
       "7:1: " + getCheckMessage(MSG_KEY),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocBlockTagLocationCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocBlockTagLocationCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.JavadocTokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class JavadocBlockTagLocationCheckTest extends AbstractModuleTestSupport {
+final class JavadocBlockTagLocationCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class JavadocBlockTagLocationCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final JavadocBlockTagLocationCheck checkObj = new JavadocBlockTagLocationCheck();
     final int[] expected = {
       JavadocTokenTypes.TEXT,
@@ -46,7 +46,7 @@ public class JavadocBlockTagLocationCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testCorrect() throws Exception {
+  void correct() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputJavadocBlockTagLocationCorrect.java"), expected);
@@ -61,7 +61,7 @@ public class JavadocBlockTagLocationCheckTest extends AbstractModuleTestSupport
    * @throws Exception if exception occurs during verification process.
    */
   @Test
-  public void testMultilineCodeBlock() throws Exception {
+  void multilineCodeBlock() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -69,7 +69,7 @@ public class JavadocBlockTagLocationCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testIncorrect() throws Exception {
+  void incorrect() throws Exception {
     final String[] expected = {
       "15: " + getCheckMessage(MSG_BLOCK_TAG_LOCATION, "author"),
       "16: " + getCheckMessage(MSG_BLOCK_TAG_LOCATION, "since"),
@@ -83,7 +83,7 @@ public class JavadocBlockTagLocationCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testCustomTags() throws Exception {
+  void customTags() throws Exception {
     final String[] expected = {
       "14: " + getCheckMessage(MSG_BLOCK_TAG_LOCATION, "apiNote"),
       "14: " + getCheckMessage(MSG_BLOCK_TAG_LOCATION, "implNote"),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocContentLocationCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocContentLocationCheckTest.java
@@ -28,7 +28,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class JavadocContentLocationCheckTest extends AbstractModuleTestSupport {
+final class JavadocContentLocationCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -36,7 +36,7 @@ public class JavadocContentLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final JavadocContentLocationCheck checkObj = new JavadocContentLocationCheck();
     final int[] expected = {TokenTypes.BLOCK_COMMENT_BEGIN};
     assertWithMessage("Acceptable tokens are invalid")
@@ -45,7 +45,7 @@ public class JavadocContentLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetDefaultTokens() {
+  void getDefaultTokens() {
     final JavadocContentLocationCheck checkObj = new JavadocContentLocationCheck();
     final int[] expected = {TokenTypes.BLOCK_COMMENT_BEGIN};
     assertWithMessage("Default tokens are invalid")
@@ -54,7 +54,7 @@ public class JavadocContentLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "17:5: " + getCheckMessage(MSG_JAVADOC_CONTENT_SECOND_LINE),
       "21:5: " + getCheckMessage(MSG_JAVADOC_CONTENT_SECOND_LINE),
@@ -63,7 +63,7 @@ public class JavadocContentLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFirstLine() throws Exception {
+  void firstLine() throws Exception {
     final String[] expected = {
       "12:5: " + getCheckMessage(MSG_JAVADOC_CONTENT_FIRST_LINE),
       "21:5: " + getCheckMessage(MSG_JAVADOC_CONTENT_FIRST_LINE),
@@ -72,7 +72,7 @@ public class JavadocContentLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackage() throws Exception {
+  void testPackage() throws Exception {
     final String[] expected = {
       "8:1: " + getCheckMessage(MSG_JAVADOC_CONTENT_SECOND_LINE),
     };
@@ -80,7 +80,7 @@ public class JavadocContentLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInterface() throws Exception {
+  void testInterface() throws Exception {
     final String[] expected = {
       "10:1: " + getCheckMessage(MSG_JAVADOC_CONTENT_FIRST_LINE),
     };
@@ -88,14 +88,14 @@ public class JavadocContentLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOptionalSpacesAndAsterisks() throws Exception {
+  void optionalSpacesAndAsterisks() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputJavadocContentLocationTrailingSpace.java"), expected);
   }
 
   @Test
-  public void testTrimOptionProperty() throws Exception {
+  void trimOptionProperty() throws Exception {
     final String[] expected = {
       "12:5: " + getCheckMessage(MSG_JAVADOC_CONTENT_FIRST_LINE),
       "21:5: " + getCheckMessage(MSG_JAVADOC_CONTENT_FIRST_LINE),
@@ -105,7 +105,7 @@ public class JavadocContentLocationCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault2() throws Exception {
+  void default2() throws Exception {
     final String[] expected = {
       "9:1: " + getCheckMessage(MSG_JAVADOC_CONTENT_SECOND_LINE),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocMethodCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocMethodCheckTest.java
@@ -34,7 +34,7 @@ import java.lang.reflect.Constructor;
 import java.lang.reflect.Method;
 import org.junit.jupiter.api.Test;
 
-public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
+final class JavadocMethodCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -42,7 +42,7 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final JavadocMethodCheck javadocMethodCheck = new JavadocMethodCheck();
 
     final int[] actual = javadocMethodCheck.getAcceptableTokens();
@@ -61,19 +61,19 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void extendAnnotationTest() throws Exception {
+  void extendAnnotationTest() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocMethodExtendAnnotation.java"), expected);
   }
 
   @Test
-  public void allowedAnnotationsTest() throws Exception {
+  void allowedAnnotationsTest() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocMethodAllowedAnnotations.java"), expected);
   }
 
   @Test
-  public void testThrowsDetection() throws Exception {
+  void throwsDetection() throws Exception {
     final String[] expected = {
       "25:19: " + getCheckMessage(MSG_EXPECTED_TAG, "@throws", "UnsupportedOperationException"),
       "37:23: " + getCheckMessage(MSG_EXPECTED_TAG, "@throws", "UnsupportedOperationException"),
@@ -94,7 +94,7 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExtraThrows() throws Exception {
+  void extraThrows() throws Exception {
     final String[] expected = {
       "54:56: " + getCheckMessage(MSG_EXPECTED_TAG, "@throws", "IllegalStateException"),
       "70:23: " + getCheckMessage(MSG_EXPECTED_TAG, "@throws", "IllegalArgumentException"),
@@ -107,7 +107,7 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreThrows() throws Exception {
+  void ignoreThrows() throws Exception {
     final String[] expected = {
       "40:23: " + getCheckMessage(MSG_EXPECTED_TAG, "@throws", "IllegalArgumentException"),
       "43:23: " + getCheckMessage(MSG_EXPECTED_TAG, "@throws", "IllegalStateException"),
@@ -119,7 +119,7 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTags() throws Exception {
+  void tags() throws Exception {
     final String[] expected = {
       "30:9: " + getCheckMessage(MSG_UNUSED_TAG, "@param", "unused"),
       "37: " + getCheckMessage(MSG_RETURN_EXPECTED),
@@ -148,7 +148,7 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStrictJavadoc() throws Exception {
+  void strictJavadoc() throws Exception {
     final String[] expected = {
       "77:29: " + getCheckMessage(MSG_EXPECTED_TAG, "@param", "aA"),
       "82:22: " + getCheckMessage(MSG_EXPECTED_TAG, "@param", "aA"),
@@ -160,14 +160,14 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoJavadoc() throws Exception {
+  void noJavadoc() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocMethodPublicOnly1.java"), expected);
   }
 
   // pre 1.4 relaxed mode is roughly equivalent with check=protected
   @Test
-  public void testRelaxedJavadoc() throws Exception {
+  void relaxedJavadoc() throws Exception {
     final String[] expected = {
       "87:41: " + getCheckMessage(MSG_EXPECTED_TAG, "@param", "aA"),
       "92:37: " + getCheckMessage(MSG_EXPECTED_TAG, "@param", "aA"),
@@ -176,19 +176,19 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testScopeInnerInterfacesPublic() throws Exception {
+  void scopeInnerInterfacesPublic() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocMethodScopeInnerInterfaces.java"), expected);
   }
 
   @Test
-  public void testScopeAnonInnerPrivate() throws Exception {
+  void scopeAnonInnerPrivate() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocMethodScopeAnonInner.java"), expected);
   }
 
   @Test
-  public void testScopes() throws Exception {
+  void scopes() throws Exception {
     final String[] expected = {
       "27: " + getCheckMessage(MSG_UNUSED_TAG_GENERAL),
       "29: " + getCheckMessage(MSG_UNUSED_TAG_GENERAL),
@@ -199,7 +199,7 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testScopes2() throws Exception {
+  void scopes2() throws Exception {
     final String[] expected = {
       "27: " + getCheckMessage(MSG_UNUSED_TAG_GENERAL),
       "29: " + getCheckMessage(MSG_UNUSED_TAG_GENERAL),
@@ -209,7 +209,7 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExcludeScope() throws Exception {
+  void excludeScope() throws Exception {
     final String[] expected = {
       "27: " + getCheckMessage(MSG_UNUSED_TAG_GENERAL),
       "31: " + getCheckMessage(MSG_UNUSED_TAG_GENERAL),
@@ -220,21 +220,21 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowMissingJavadocTags() throws Exception {
+  void allowMissingJavadocTags() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputJavadocMethodMissingJavadocNoMissingTags.java"), expected);
   }
 
   @Test
-  public void testSurroundingAccessModifier() throws Exception {
+  void surroundingAccessModifier() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputJavadocMethodSurroundingAccessModifier.java"), expected);
   }
 
   @Test
-  public void testDoAllowMissingJavadocTagsByDefault() throws Exception {
+  void doAllowMissingJavadocTagsByDefault() throws Exception {
     final String[] expected = {
       "23: " + getCheckMessage(MSG_RETURN_EXPECTED),
       "34:26: " + getCheckMessage(MSG_EXPECTED_TAG, "@param", "number"),
@@ -247,13 +247,13 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSetterGetter() throws Exception {
+  void setterGetter() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocMethodSetterGetter.java"), expected);
   }
 
   @Test
-  public void testTypeParamsTags() throws Exception {
+  void typeParamsTags() throws Exception {
     final String[] expected = {
       "37:8: " + getCheckMessage(MSG_UNUSED_TAG, "@param", "<BB>"),
       "40:13: " + getCheckMessage(MSG_EXPECTED_TAG, "@param", "<Z>"),
@@ -264,7 +264,7 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowUndocumentedParamsTags() throws Exception {
+  void allowUndocumentedParamsTags() throws Exception {
     final String[] expected = {
       "33:6: " + getCheckMessage(MSG_UNUSED_TAG, "@param", "unexpectedParam"),
       "34:6: " + getCheckMessage(MSG_UNUSED_TAG, "@param", "unexpectedParam2"),
@@ -279,25 +279,25 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test11684081() throws Exception {
+  void test11684081() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocMethod_01.java"), expected);
   }
 
   @Test
-  public void test11684082() throws Exception {
+  void test11684082() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocMethod_02.java"), expected);
   }
 
   @Test
-  public void test11684083() throws Exception {
+  void test11684083() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocMethod_03.java"), expected);
   }
 
   @Test
-  public void testGenerics() throws Exception {
+  void generics() throws Exception {
     final String[] expected = {
       "29:34: " + getCheckMessage(MSG_EXPECTED_TAG, "@throws", "RE"),
       "46:13: " + getCheckMessage(MSG_EXPECTED_TAG, "@param", "<NPE>"),
@@ -308,13 +308,13 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test1379666() throws Exception {
+  void test1379666() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocMethod_1379666.java"), expected);
   }
 
   @Test
-  public void testInheritDoc() throws Exception {
+  void inheritDoc() throws Exception {
     final String[] expected = {
       "18:5: " + getCheckMessage(MSG_INVALID_INHERIT_DOC),
       "23:5: " + getCheckMessage(MSG_INVALID_INHERIT_DOC),
@@ -327,7 +327,7 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowToSkipOverridden() throws Exception {
+  void allowToSkipOverridden() throws Exception {
     final String[] expected = {
       "19:8: " + getCheckMessage(MSG_UNUSED_TAG, "@param", "BAD"),
       "30:8: " + getCheckMessage(MSG_UNUSED_TAG, "@param", "BAD"),
@@ -336,19 +336,19 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJava8ReceiverParameter() throws Exception {
+  void java8ReceiverParameter() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocMethodReceiverParameter.java"), expected);
   }
 
   @Test
-  public void testJavadocInMethod() throws Exception {
+  void javadocInMethod() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocMethodJavadocInMethod.java"), expected);
   }
 
   @Test
-  public void testConstructor() throws Exception {
+  void constructor() throws Exception {
     final String[] expected = {
       "21:49: " + getCheckMessage(MSG_EXPECTED_TAG, "@param", "p1"),
       "24:50: " + getCheckMessage(MSG_EXPECTED_TAG, "@param", "p1"),
@@ -357,7 +357,7 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocMethodRecordsAndCompactCtors() throws Exception {
+  void javadocMethodRecordsAndCompactCtors() throws Exception {
     final String[] expected = {
       "29:27: " + getCheckMessage(MSG_EXPECTED_TAG, "@throws", "IllegalArgumentException"),
       "43:27: "
@@ -375,7 +375,7 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final int[] expected = {
       TokenTypes.CLASS_DEF, TokenTypes.INTERFACE_DEF, TokenTypes.ENUM_DEF, TokenTypes.RECORD_DEF,
     };
@@ -385,7 +385,7 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokenToString() throws Exception {
+  void tokenToString() throws Exception {
     final Class<?> tokenType =
         Class.forName(
             "com.puppycrawl.tools.checkstyle.checks.javadoc." + "JavadocMethodCheck$Token");
@@ -399,20 +399,20 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithoutLogErrors() throws Exception {
+  void withoutLogErrors() throws Exception {
     verifyWithInlineConfigParser(
         getPath("InputJavadocMethodLoadErrors.java"), CommonUtil.EMPTY_STRING_ARRAY);
   }
 
   @Test
-  public void testCompilationUnit() throws Exception {
+  void compilationUnit() throws Exception {
     verifyWithInlineConfigParser(
         getNonCompilablePath("InputJavadocMethodCompilationUnit.java"),
         CommonUtil.EMPTY_STRING_ARRAY);
   }
 
   @Test
-  public void testDefaultAccessModifier() throws Exception {
+  void defaultAccessModifier() throws Exception {
     final String[] expected = {
       "21:32: " + getCheckMessage(MSG_EXPECTED_TAG, "@param", "a"),
       "26:43: " + getCheckMessage(MSG_EXPECTED_TAG, "@param", "b"),
@@ -421,7 +421,7 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAccessModifierEnum() throws Exception {
+  void accessModifierEnum() throws Exception {
     final String[] expected = {
       "27:17: " + getCheckMessage(MSG_EXPECTED_TAG, "@param", "i"),
     };
@@ -429,7 +429,7 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCustomMessages() throws Exception {
+  void customMessages() throws Exception {
     final String msgReturnExpectedCustom = "@return tag should be present and have description :)";
     final String msgUnusedTagCustom = "Unused @param tag for 'unused' :)";
     final String msgExpectedTagCustom = "Expected @param tag for 'a' :)";
@@ -443,7 +443,7 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test1() throws Exception {
+  void test1() throws Exception {
     final String[] expected = {
       "23: " + getCheckMessage(MSG_RETURN_EXPECTED),
     };
@@ -451,7 +451,7 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test2() throws Exception {
+  void test2() throws Exception {
     final String[] expected = {
       "15:8: " + getCheckMessage(MSG_UNUSED_TAG, "@param", "<"),
       "19:13: " + getCheckMessage(MSG_EXPECTED_TAG, "@param", "<X>"),
@@ -460,7 +460,7 @@ public class JavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test3() throws Exception {
+  void test3() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocMethod3.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocMissingLeadingAsteriskCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocMissingLeadingAsteriskCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.JavadocTokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class JavadocMissingLeadingAsteriskCheckTest extends AbstractModuleTestSupport {
+final class JavadocMissingLeadingAsteriskCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class JavadocMissingLeadingAsteriskCheckTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final JavadocMissingLeadingAsteriskCheck checkObj = new JavadocMissingLeadingAsteriskCheck();
     final int[] expected = {
       JavadocTokenTypes.NEWLINE,
@@ -46,14 +46,14 @@ public class JavadocMissingLeadingAsteriskCheckTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testCorrect() throws Exception {
+  void correct() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputJavadocMissingLeadingAsteriskCorrect.java"), expected);
   }
 
   @Test
-  public void testIncorrect() throws Exception {
+  void incorrect() throws Exception {
     final String[] expected = {
       "13: " + getCheckMessage(MSG_MISSING_ASTERISK),
       "18: " + getCheckMessage(MSG_MISSING_ASTERISK),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocMissingWhitespaceAfterAsteriskCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocMissingWhitespaceAfterAsteriskCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.JavadocTokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class JavadocMissingWhitespaceAfterAsteriskCheckTest extends AbstractModuleTestSupport {
+final class JavadocMissingWhitespaceAfterAsteriskCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -36,7 +36,7 @@ public class JavadocMissingWhitespaceAfterAsteriskCheckTest extends AbstractModu
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final JavadocMissingWhitespaceAfterAsteriskCheck checkObj =
         new JavadocMissingWhitespaceAfterAsteriskCheck();
     final int[] expected = {
@@ -48,7 +48,7 @@ public class JavadocMissingWhitespaceAfterAsteriskCheckTest extends AbstractModu
   }
 
   @Test
-  public void testGetRequiredJavadocTokens() {
+  void getRequiredJavadocTokens() {
     final JavadocMissingWhitespaceAfterAsteriskCheck checkObj =
         new JavadocMissingWhitespaceAfterAsteriskCheck();
     final int[] expected = {
@@ -60,7 +60,7 @@ public class JavadocMissingWhitespaceAfterAsteriskCheckTest extends AbstractModu
   }
 
   @Test
-  public void testValid() throws Exception {
+  void valid() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -68,7 +68,7 @@ public class JavadocMissingWhitespaceAfterAsteriskCheckTest extends AbstractModu
   }
 
   @Test
-  public void testValidWithTabCharacter() throws Exception {
+  void validWithTabCharacter() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -76,7 +76,7 @@ public class JavadocMissingWhitespaceAfterAsteriskCheckTest extends AbstractModu
   }
 
   @Test
-  public void testInvalid() throws Exception {
+  void invalid() throws Exception {
     final String[] expected = {
       "10:4: " + getCheckMessage(MSG_KEY),
       "16:7: " + getCheckMessage(MSG_KEY),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocNodeImplTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocNodeImplTest.java
@@ -24,10 +24,10 @@ import static com.google.common.truth.Truth.assertWithMessage;
 import com.puppycrawl.tools.checkstyle.api.JavadocTokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class JavadocNodeImplTest {
+final class JavadocNodeImplTest {
 
   @Test
-  public void testToString() {
+  void testToString() {
     final JavadocNodeImpl javadocNode = new JavadocNodeImpl();
     javadocNode.setType(JavadocTokenTypes.CODE_LITERAL);
     javadocNode.setLineNumber(1);
@@ -43,7 +43,7 @@ public class JavadocNodeImplTest {
   }
 
   @Test
-  public void testGetColumnNumber() {
+  void getColumnNumber() {
     final JavadocNodeImpl javadocNode = new JavadocNodeImpl();
     javadocNode.setColumnNumber(1);
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocPackageCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocPackageCheckTest.java
@@ -23,15 +23,15 @@ import static com.google.common.truth.Truth.assertWithMessage;
 import static com.puppycrawl.tools.checkstyle.checks.javadoc.JavadocPackageCheck.MSG_LEGACY_PACKAGE_HTML;
 import static com.puppycrawl.tools.checkstyle.checks.javadoc.JavadocPackageCheck.MSG_PACKAGE_INFO;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
 import com.puppycrawl.tools.checkstyle.api.FileText;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.io.File;
-import java.util.Collections;
 import org.junit.jupiter.api.Test;
 
-public class JavadocPackageCheckTest extends AbstractModuleTestSupport {
+final class JavadocPackageCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -39,7 +39,7 @@ public class JavadocPackageCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMissing() throws Exception {
+  void missing() throws Exception {
     final String[] expected = {
       "1: " + getCheckMessage(MSG_PACKAGE_INFO),
     };
@@ -47,7 +47,7 @@ public class JavadocPackageCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMissingWithAllowLegacy() throws Exception {
+  void missingWithAllowLegacy() throws Exception {
     final String[] expected = {
       "1: " + getCheckMessage(MSG_PACKAGE_INFO),
     };
@@ -55,7 +55,7 @@ public class JavadocPackageCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithMultipleFiles() throws Exception {
+  void withMultipleFiles() throws Exception {
     final String[] expected = {
       "1: " + getCheckMessage(MSG_PACKAGE_INFO),
     };
@@ -66,7 +66,7 @@ public class JavadocPackageCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBoth() throws Exception {
+  void both() throws Exception {
     final String[] expected = {
       "1: " + getCheckMessage(MSG_LEGACY_PACKAGE_HTML),
     };
@@ -75,7 +75,7 @@ public class JavadocPackageCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHtmlDisallowed() throws Exception {
+  void htmlDisallowed() throws Exception {
     final String[] expected = {
       "1: " + getCheckMessage(MSG_PACKAGE_INFO),
     };
@@ -84,7 +84,7 @@ public class JavadocPackageCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHtmlAllowed() throws Exception {
+  void htmlAllowed() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("pkghtml" + File.separator + "InputJavadocPackageHtmlIgnored2.java"),
@@ -93,7 +93,7 @@ public class JavadocPackageCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotation() throws Exception {
+  void annotation() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("annotation" + File.separator + "package-info.java"), expected);
@@ -104,10 +104,10 @@ public class JavadocPackageCheckTest extends AbstractModuleTestSupport {
    * invalid canonical path.
    */
   @Test
-  public void testCheckstyleExceptionIfFailedToGetCanonicalPathToFile() {
+  void checkstyleExceptionIfFailedToGetCanonicalPathToFile() {
     final JavadocPackageCheck check = new JavadocPackageCheck();
     final File fileWithInvalidPath = new File("\u0000\u0000\u0000");
-    final FileText mockFileText = new FileText(fileWithInvalidPath, Collections.emptyList());
+    final FileText mockFileText = new FileText(fileWithInvalidPath, ImmutableList.of());
     final String expectedExceptionMessage =
         "Exception while getting canonical path to file " + fileWithInvalidPath.getPath();
     try {
@@ -121,13 +121,13 @@ public class JavadocPackageCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonJava() throws Exception {
+  void nonJava() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocPackageNotJava.txt"), expected);
   }
 
   @Test
-  public void testWithFileWithoutParent() throws Exception {
+  void withFileWithoutParent() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("annotation" + File.separator + "package-info.java"), expected);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocParagraphCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocParagraphCheckTest.java
@@ -30,7 +30,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class JavadocParagraphCheckTest extends AbstractModuleTestSupport {
+final class JavadocParagraphCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -38,7 +38,7 @@ public class JavadocParagraphCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final JavadocParagraphCheck checkObj = new JavadocParagraphCheck();
     final int[] expected = {TokenTypes.BLOCK_COMMENT_BEGIN};
     assertWithMessage("Default required tokens are invalid")
@@ -47,14 +47,14 @@ public class JavadocParagraphCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCorrect() throws Exception {
+  void correct() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputJavadocParagraphCorrect.java"), expected);
   }
 
   @Test
-  public void testIncorrect() throws Exception {
+  void incorrect() throws Exception {
     final String[] expected = {
       "13: " + getCheckMessage(MSG_MISPLACED_TAG),
       "13: " + getCheckMessage(MSG_LINE_BEFORE),
@@ -97,7 +97,7 @@ public class JavadocParagraphCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowNewlineParagraph() throws Exception {
+  void allowNewlineParagraph() throws Exception {
     final String[] expected = {
       "13: " + getCheckMessage(MSG_LINE_BEFORE),
       "14: " + getCheckMessage(MSG_LINE_BEFORE),
@@ -123,7 +123,7 @@ public class JavadocParagraphCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocParagraph() throws Exception {
+  void javadocParagraph() throws Exception {
     final String[] expected = {
       "19: " + getCheckMessage(MSG_LINE_BEFORE),
       "30: " + getCheckMessage(MSG_MISPLACED_TAG),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocStyleCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocStyleCheckTest.java
@@ -32,7 +32,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.io.File;
 import org.junit.jupiter.api.Test;
 
-public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
+final class JavadocStyleCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -40,7 +40,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final JavadocStyleCheck javadocStyleCheck = new JavadocStyleCheck();
 
     final int[] actual = javadocStyleCheck.getAcceptableTokens();
@@ -63,7 +63,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocStyleDefaultSettingsOne() throws Exception {
+  void javadocStyleDefaultSettingsOne() throws Exception {
     final String[] expected = {
       "24: " + getCheckMessage(MSG_NO_PERIOD),
       "50: " + getCheckMessage(MSG_NO_PERIOD),
@@ -84,7 +84,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocStyleDefaultSettingsTwo() throws Exception {
+  void javadocStyleDefaultSettingsTwo() throws Exception {
     final String[] expected = {
       "26:39: " + getCheckMessage(MSG_EXTRA_HTML, "</img>"),
       "72:8: " + getCheckMessage(MSG_UNCLOSED_HTML, "<blockquote>"),
@@ -96,7 +96,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocStyleDefaultSettingsThree() throws Exception {
+  void javadocStyleDefaultSettingsThree() throws Exception {
     final String[] expected = {
       "109: " + getCheckMessage(MSG_NO_PERIOD),
     };
@@ -105,7 +105,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocStyleDefaultSettingsFour() throws Exception {
+  void javadocStyleDefaultSettingsFour() throws Exception {
     final String[] expected = {
       "30:33: " + getCheckMessage(MSG_UNCLOSED_HTML, "<code>"),
       "42: " + getCheckMessage(MSG_NO_PERIOD),
@@ -121,7 +121,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocStyleFirstSentenceOne() throws Exception {
+  void javadocStyleFirstSentenceOne() throws Exception {
     final String[] expected = {
       "24: " + getCheckMessage(MSG_NO_PERIOD),
       "50: " + getCheckMessage(MSG_NO_PERIOD),
@@ -134,7 +134,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocStyleFirstSentenceTwo() throws Exception {
+  void javadocStyleFirstSentenceTwo() throws Exception {
     final String[] expected = {
       "67: " + getCheckMessage(MSG_NO_PERIOD), "101: " + getCheckMessage(MSG_NO_PERIOD),
     };
@@ -143,14 +143,14 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocStyleFirstSentenceThree() throws Exception {
+  void javadocStyleFirstSentenceThree() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputJavadocStyleFirstSentenceThree.java"), expected);
   }
 
   @Test
-  public void testJavadocStyleFirstSentenceFour() throws Exception {
+  void javadocStyleFirstSentenceFour() throws Exception {
     final String[] expected = {
       "40: " + getCheckMessage(MSG_NO_PERIOD),
       "51: " + getCheckMessage(MSG_NO_PERIOD),
@@ -164,7 +164,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocStyleFirstSentenceFormatOne() throws Exception {
+  void javadocStyleFirstSentenceFormatOne() throws Exception {
     final String[] expected = {
       "24: " + getCheckMessage(MSG_NO_PERIOD),
       "35: " + getCheckMessage(MSG_NO_PERIOD),
@@ -179,7 +179,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocStyleFirstSentenceFormatTwo() throws Exception {
+  void javadocStyleFirstSentenceFormatTwo() throws Exception {
     final String[] expected = {
       "74: " + getCheckMessage(MSG_NO_PERIOD), "108: " + getCheckMessage(MSG_NO_PERIOD),
     };
@@ -188,7 +188,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocStyleFirstSentenceFormatThree() throws Exception {
+  void javadocStyleFirstSentenceFormatThree() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -196,7 +196,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocStyleFirstSentenceFormatFour() throws Exception {
+  void javadocStyleFirstSentenceFormatFour() throws Exception {
     final String[] expected = {
       "40: " + getCheckMessage(MSG_NO_PERIOD),
       "51: " + getCheckMessage(MSG_NO_PERIOD),
@@ -211,7 +211,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHtml1() throws Exception {
+  void html1() throws Exception {
     final String[] expected = {
       "59:11: " + getCheckMessage(MSG_UNCLOSED_HTML, "<b>"),
       "62:7: " + getCheckMessage(MSG_EXTRA_HTML, "</td>"),
@@ -228,7 +228,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHtml2() throws Exception {
+  void html2() throws Exception {
     final String[] expected = {
       "68:8: " + getCheckMessage(MSG_UNCLOSED_HTML, "<blockquote>"),
     };
@@ -237,7 +237,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHtml3() throws Exception {
+  void html3() throws Exception {
     final String[] expected = {
       "103:21: " + getCheckMessage(MSG_EXTRA_HTML, "</string>"),
     };
@@ -246,7 +246,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHtml4() throws Exception {
+  void html4() throws Exception {
     final String[] expected = {
       "29:33: " + getCheckMessage(MSG_UNCLOSED_HTML, "<code>"),
       "47:11: " + getCheckMessage(MSG_UNCLOSED_HTML, "<b>"),
@@ -256,28 +256,28 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHtmlComment() throws Exception {
+  void htmlComment() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputJavadocStyleHtmlComment.java"), expected);
   }
 
   @Test
-  public void testOnInputWithNoJavadoc1() throws Exception {
+  void onInputWithNoJavadoc1() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputJavadocStyleNoJavadoc1.java"), expected);
   }
 
   @Test
-  public void testOnInputWithNoJavadoc2() throws Exception {
+  void onInputWithNoJavadoc2() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputJavadocStyleNoJavadoc2.java"), expected);
   }
 
   @Test
-  public void testScopePublic1() throws Exception {
+  void scopePublic1() throws Exception {
     final String[] expected = {
       "78: " + getCheckMessage(MSG_NO_PERIOD),
       "79:31: " + getCheckMessage(MSG_EXTRA_HTML, "</code>"),
@@ -288,7 +288,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testScopePublic2() throws Exception {
+  void scopePublic2() throws Exception {
     final String[] expected = {
       "83: " + getCheckMessage(MSG_EMPTY),
       "102: " + getCheckMessage(MSG_EMPTY),
@@ -299,7 +299,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testScopePublic3() throws Exception {
+  void scopePublic3() throws Exception {
     final String[] expected = {
       "104:21: " + getCheckMessage(MSG_EXTRA_HTML, "</string>"),
     };
@@ -308,7 +308,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testScopePublic4() throws Exception {
+  void scopePublic4() throws Exception {
     final String[] expected = {
       "51: " + getCheckMessage(MSG_NO_PERIOD),
       "56: " + getCheckMessage(MSG_NO_PERIOD),
@@ -319,7 +319,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testScopeProtected1() throws Exception {
+  void scopeProtected1() throws Exception {
     final String[] expected = {
       "67: " + getCheckMessage(MSG_NO_PERIOD),
       "68:23: " + getCheckMessage(MSG_UNCLOSED_HTML, "<b>"),
@@ -332,7 +332,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testScopeProtected2() throws Exception {
+  void scopeProtected2() throws Exception {
     final String[] expected = {
       "83: " + getCheckMessage(MSG_EMPTY),
       "87: " + getCheckMessage(MSG_EMPTY),
@@ -344,7 +344,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testScopeProtected3() throws Exception {
+  void scopeProtected3() throws Exception {
     final String[] expected = {
       "104:21: " + getCheckMessage(MSG_EXTRA_HTML, "</string>"),
     };
@@ -353,7 +353,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testScopeProtected4() throws Exception {
+  void scopeProtected4() throws Exception {
     final String[] expected = {
       "51: " + getCheckMessage(MSG_NO_PERIOD),
       "56: " + getCheckMessage(MSG_NO_PERIOD),
@@ -364,7 +364,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testScopePackage1() throws Exception {
+  void scopePackage1() throws Exception {
     final String[] expected = {
       "67: " + getCheckMessage(MSG_NO_PERIOD),
       "68:24: " + getCheckMessage(MSG_UNCLOSED_HTML, "<b>"),
@@ -379,7 +379,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testScopePackage2() throws Exception {
+  void scopePackage2() throws Exception {
     final String[] expected = {
       "83: " + getCheckMessage(MSG_EMPTY),
       "87: " + getCheckMessage(MSG_EMPTY),
@@ -392,7 +392,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testScopePackage3() throws Exception {
+  void scopePackage3() throws Exception {
     final String[] expected = {
       "104:21: " + getCheckMessage(MSG_EXTRA_HTML, "</string>"),
     };
@@ -401,7 +401,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testScopePackage4() throws Exception {
+  void scopePackage4() throws Exception {
     final String[] expected = {
       "51: " + getCheckMessage(MSG_NO_PERIOD),
       "56: " + getCheckMessage(MSG_NO_PERIOD),
@@ -414,14 +414,14 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyJavadoc1() throws Exception {
+  void emptyJavadoc1() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputJavadocStyleEmptyJavadoc1.java"), expected);
   }
 
   @Test
-  public void testEmptyJavadoc2() throws Exception {
+  void emptyJavadoc2() throws Exception {
     final String[] expected = {
       "75: " + getCheckMessage(MSG_EMPTY),
       "79: " + getCheckMessage(MSG_EMPTY),
@@ -434,21 +434,21 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyJavadoc3() throws Exception {
+  void emptyJavadoc3() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputJavadocStyleEmptyJavadoc3.java"), expected);
   }
 
   @Test
-  public void testEmptyJavadoc4() throws Exception {
+  void emptyJavadoc4() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputJavadocStyleEmptyJavadoc4.java"), expected);
   }
 
   @Test
-  public void testExcludeScope1() throws Exception {
+  void excludeScope1() throws Exception {
     final String[] expected = {
       "24: " + getCheckMessage(MSG_NO_PERIOD),
       "50: " + getCheckMessage(MSG_NO_PERIOD),
@@ -465,7 +465,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExcludeScope2() throws Exception {
+  void excludeScope2() throws Exception {
     final String[] expected = {
       "69:8: " + getCheckMessage(MSG_UNCLOSED_HTML, "<blockquote>"),
       "75: " + getCheckMessage(MSG_NO_PERIOD),
@@ -475,14 +475,14 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExcludeScope3() throws Exception {
+  void excludeScope3() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputJavadocStyleExcludeScope3.java"), expected);
   }
 
   @Test
-  public void testExcludeScope4() throws Exception {
+  void excludeScope4() throws Exception {
     final String[] expected = {
       "30:33: " + getCheckMessage(MSG_UNCLOSED_HTML, "<code>"),
       "42: " + getCheckMessage(MSG_NO_PERIOD),
@@ -495,7 +495,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void packageInfoInheritDoc() throws Exception {
+  void packageInfoInheritDoc() throws Exception {
     final String[] expected = {
       "16: " + getCheckMessage(MSG_NO_PERIOD),
     };
@@ -507,7 +507,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void packageInfoInvalid() throws Exception {
+  void packageInfoInvalid() throws Exception {
     final String[] expected = {
       "17: " + getCheckMessage(MSG_NO_PERIOD),
     };
@@ -519,7 +519,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void packageInfoAnnotation() throws Exception {
+  void packageInfoAnnotation() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -528,7 +528,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void packageInfoMissing() throws Exception {
+  void packageInfoMissing() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -536,7 +536,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void packageInfoMissingPeriod() throws Exception {
+  void packageInfoMissingPeriod() throws Exception {
     final String[] expected = {
       "16: " + getCheckMessage(MSG_NO_PERIOD),
     };
@@ -546,14 +546,14 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNothing() throws Exception {
+  void nothing() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputJavadocStyleNothing.java"), expected);
   }
 
   @Test
-  public void packageInfoValid() throws Exception {
+  void packageInfoValid() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -562,7 +562,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRestrictedTokenSet1() throws Exception {
+  void restrictedTokenSet1() throws Exception {
     final String[] expected = {
       "74: " + getCheckMessage(MSG_NO_PERIOD),
     };
@@ -571,21 +571,21 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRestrictedTokenSet2() throws Exception {
+  void restrictedTokenSet2() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputJavadocStyleRestrictedTokenSet2.java"), expected);
   }
 
   @Test
-  public void testRestrictedTokenSet3() throws Exception {
+  void restrictedTokenSet3() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputJavadocStyleRestrictedTokenSet3.java"), expected);
   }
 
   @Test
-  public void testRestrictedTokenSet4() throws Exception {
+  void restrictedTokenSet4() throws Exception {
     final String[] expected = {
       "53: " + getCheckMessage(MSG_NO_PERIOD), "86: " + getCheckMessage(MSG_NO_PERIOD),
     };
@@ -594,7 +594,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocStyleRecordsAndCompactCtors() throws Exception {
+  void javadocStyleRecordsAndCompactCtors() throws Exception {
     final String[] expected = {
       "24: " + getCheckMessage(MSG_NO_PERIOD),
       "45: " + getCheckMessage(MSG_NO_PERIOD),
@@ -614,7 +614,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHtmlTagToString() {
+  void htmlTagToString() {
     final HtmlTag tag = new HtmlTag("id", 3, 5, true, false, "<a href=\"URL\"/>");
     assertWithMessage("Invalid toString result")
         .that(tag.toString())
@@ -624,14 +624,14 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNeverEndingXmlCommentInsideJavadoc() throws Exception {
+  void neverEndingXmlCommentInsideJavadoc() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputJavadocStyleNeverEndingXmlComment.java"), expected);
   }
 
   @Test
-  public void testInterfaceMemberScopeIsPublic() throws Exception {
+  void interfaceMemberScopeIsPublic() throws Exception {
     final String[] expected = {
       "21: " + getCheckMessage(MSG_EMPTY), "25: " + getCheckMessage(MSG_EMPTY),
     };
@@ -641,7 +641,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEnumCtorScopeIsPrivate() throws Exception {
+  void enumCtorScopeIsPrivate() throws Exception {
     final String[] expected = {
       "21: " + getCheckMessage(MSG_EMPTY),
       "25: " + getCheckMessage(MSG_EMPTY),
@@ -652,7 +652,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLowerCasePropertyForTag() throws Exception {
+  void lowerCasePropertyForTag() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -660,7 +660,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocTag() throws Exception {
+  void javadocTag() throws Exception {
     final String[] expected = {
       "11: " + getCheckMessage(MSG_NO_PERIOD), "15: " + getCheckMessage(MSG_NO_PERIOD),
     };
@@ -669,7 +669,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocTag2() throws Exception {
+  void javadocTag2() throws Exception {
     final String[] expected = {
       "16: " + getCheckMessage(MSG_NO_PERIOD),
       "18:16: "
@@ -682,7 +682,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocTag3() throws Exception {
+  void javadocTag3() throws Exception {
     final String[] expected = {
       "21:4: " + getCheckMessage(MSG_EXTRA_HTML, "</body>"),
     };
@@ -691,7 +691,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocStyleCheck3() throws Exception {
+  void javadocStyleCheck3() throws Exception {
     final String[] expected = {
       "11: " + getCheckMessage(MSG_NO_PERIOD),
     };
@@ -700,7 +700,7 @@ public class JavadocStyleCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocStyleCheck4() throws Exception {
+  void javadocStyleCheck4() throws Exception {
     final String[] expected = {
       "12: " + getCheckMessage(MSG_NO_PERIOD),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocTagContinuationIndentationCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocTagContinuationIndentationCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class JavadocTagContinuationIndentationCheckTest extends AbstractModuleTestSupport {
+final class JavadocTagContinuationIndentationCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class JavadocTagContinuationIndentationCheckTest extends AbstractModuleTe
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final JavadocTagContinuationIndentationCheck checkObj =
         new JavadocTagContinuationIndentationCheck();
     final int[] expected = {TokenTypes.BLOCK_COMMENT_BEGIN};
@@ -45,14 +45,14 @@ public class JavadocTagContinuationIndentationCheckTest extends AbstractModuleTe
   }
 
   @Test
-  public void testFp() throws Exception {
+  void fp() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputJavadocTagContinuationIndentationGuavaFalsePositive.java"), expected);
   }
 
   @Test
-  public void testCheck() throws Exception {
+  void check() throws Exception {
     final String[] expected = {
       "55: " + getCheckMessage(MSG_KEY, 4),
       "117: " + getCheckMessage(MSG_KEY, 4),
@@ -73,7 +73,7 @@ public class JavadocTagContinuationIndentationCheckTest extends AbstractModuleTe
   }
 
   @Test
-  public void testCheckWithOffset3() throws Exception {
+  void checkWithOffset3() throws Exception {
     final String[] expected = {
       "15: " + getCheckMessage(MSG_KEY, 3), "27: " + getCheckMessage(MSG_KEY, 3),
     };
@@ -82,7 +82,7 @@ public class JavadocTagContinuationIndentationCheckTest extends AbstractModuleTe
   }
 
   @Test
-  public void testCheckWithDescription() throws Exception {
+  void checkWithDescription() throws Exception {
     final String[] expected = {
       "16: " + getCheckMessage(MSG_KEY, 4),
       "17: " + getCheckMessage(MSG_KEY, 4),
@@ -96,7 +96,7 @@ public class JavadocTagContinuationIndentationCheckTest extends AbstractModuleTe
   }
 
   @Test
-  public void testBlockTag() throws Exception {
+  void blockTag() throws Exception {
     final String[] expected = {
       "21: " + getCheckMessage(MSG_KEY, 4),
       "32: " + getCheckMessage(MSG_KEY, 4),
@@ -128,7 +128,7 @@ public class JavadocTagContinuationIndentationCheckTest extends AbstractModuleTe
   }
 
   @Test
-  public void testContinuationIndentation() throws Exception {
+  void continuationIndentation() throws Exception {
     final String[] expected = {
       "23: " + getCheckMessage(MSG_KEY, 4),
     };
@@ -136,7 +136,7 @@ public class JavadocTagContinuationIndentationCheckTest extends AbstractModuleTe
   }
 
   @Test
-  public void testJavadocTagContinuationIndentationCheck1() throws Exception {
+  void javadocTagContinuationIndentationCheck1() throws Exception {
     final String[] expected = {
       "16: " + getCheckMessage(MSG_KEY, 4),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocTagInfoTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocTagInfoTest.java
@@ -26,14 +26,14 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import java.lang.reflect.Method;
 import org.junit.jupiter.api.Test;
 
-public class JavadocTagInfoTest {
+final class JavadocTagInfoTest {
 
   /* Additional test for jacoco, since valueOf()
    * is generated by javac and jacoco reports that
    * valueOf() is uncovered.
    */
   @Test
-  public void testJavadocTagInfoValueOf() {
+  void javadocTagInfoValueOf() {
     final JavadocTagInfo tag = JavadocTagInfo.valueOf("AUTHOR");
     assertWithMessage("Invalid valueOf result").that(tag).isEqualTo(JavadocTagInfo.AUTHOR);
   }
@@ -43,7 +43,7 @@ public class JavadocTagInfoTest {
    * valueOf() is uncovered.
    */
   @Test
-  public void testTypeValueOf() {
+  void typeValueOf() {
     final JavadocTagInfo.Type type = JavadocTagInfo.Type.valueOf("BLOCK");
     assertWithMessage("Invalid valueOf result").that(type).isEqualTo(JavadocTagInfo.Type.BLOCK);
   }
@@ -53,7 +53,7 @@ public class JavadocTagInfoTest {
    * values() is uncovered.
    */
   @Test
-  public void testTypeValues() {
+  void typeValues() {
     final JavadocTagInfo.Type[] expected = {
       JavadocTagInfo.Type.BLOCK, JavadocTagInfo.Type.INLINE,
     };
@@ -62,7 +62,7 @@ public class JavadocTagInfoTest {
   }
 
   @Test
-  public void testAuthor() {
+  void author() {
     final DetailAstImpl ast = new DetailAstImpl();
 
     final int[] validTypes = {
@@ -86,7 +86,7 @@ public class JavadocTagInfoTest {
   }
 
   @Test
-  public void testOthers() throws ReflectiveOperationException {
+  void others() throws ReflectiveOperationException {
     final JavadocTagInfo[] tags = {
       JavadocTagInfo.CODE,
       JavadocTagInfo.DOC_ROOT,
@@ -137,7 +137,7 @@ public class JavadocTagInfoTest {
   }
 
   @Test
-  public void testDeprecated() throws ReflectiveOperationException {
+  void deprecated() throws ReflectiveOperationException {
     final DetailAstImpl ast = new DetailAstImpl();
     final DetailAstImpl astParent = new DetailAstImpl();
     astParent.setType(TokenTypes.LITERAL_CATCH);
@@ -176,7 +176,7 @@ public class JavadocTagInfoTest {
   }
 
   @Test
-  public void testSerial() throws ReflectiveOperationException {
+  void serial() throws ReflectiveOperationException {
     final DetailAstImpl ast = new DetailAstImpl();
     final DetailAstImpl astParent = new DetailAstImpl();
     astParent.setType(TokenTypes.LITERAL_CATCH);
@@ -207,7 +207,7 @@ public class JavadocTagInfoTest {
   }
 
   @Test
-  public void testException() {
+  void exception() {
     final DetailAstImpl ast = new DetailAstImpl();
 
     final int[] validTypes = {
@@ -227,7 +227,7 @@ public class JavadocTagInfoTest {
   }
 
   @Test
-  public void testThrows() {
+  void testThrows() {
     final DetailAstImpl ast = new DetailAstImpl();
 
     final int[] validTypes = {
@@ -247,7 +247,7 @@ public class JavadocTagInfoTest {
   }
 
   @Test
-  public void testVersions() {
+  void versions() {
     final DetailAstImpl ast = new DetailAstImpl();
 
     final int[] validTypes = {
@@ -271,7 +271,7 @@ public class JavadocTagInfoTest {
   }
 
   @Test
-  public void testParam() {
+  void param() {
     final DetailAstImpl ast = new DetailAstImpl();
 
     final int[] validTypes = {
@@ -291,7 +291,7 @@ public class JavadocTagInfoTest {
   }
 
   @Test
-  public void testReturn() {
+  void testReturn() {
     final DetailAstImpl ast = new DetailAstImpl();
     final DetailAstImpl astChild = new DetailAstImpl();
     astChild.setType(TokenTypes.TYPE);
@@ -322,7 +322,7 @@ public class JavadocTagInfoTest {
   }
 
   @Test
-  public void testSerialField() {
+  void serialField() {
     final DetailAstImpl ast = new DetailAstImpl();
     final DetailAstImpl astChild = new DetailAstImpl();
     astChild.setType(TokenTypes.TYPE);
@@ -359,7 +359,7 @@ public class JavadocTagInfoTest {
   }
 
   @Test
-  public void testSerialData() {
+  void serialData() {
     final DetailAstImpl ast = new DetailAstImpl();
     ast.setType(TokenTypes.METHOD_DEF);
     final DetailAstImpl astChild = new DetailAstImpl();
@@ -389,7 +389,7 @@ public class JavadocTagInfoTest {
   }
 
   @Test
-  public void testCoverage() {
+  void coverage() {
     assertWithMessage("Invalid type")
         .that(JavadocTagInfo.VERSION.getType())
         .isEqualTo(JavadocTagInfo.Type.BLOCK);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocTagTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocTagTest.java
@@ -25,14 +25,14 @@ import static com.google.common.truth.Truth.assertWithMessage;
 import com.puppycrawl.tools.checkstyle.utils.JavadocUtil;
 import org.junit.jupiter.api.Test;
 
-public class JavadocTagTest {
+final class JavadocTagTest {
 
   /* Additional test for jacoco, since valueOf()
    * is generated by javac and jacoco reports that
    * valueOf() is uncovered.
    */
   @Test
-  public void testJavadocTagTypeValueOf() {
+  void javadocTagTypeValueOf() {
     final JavadocUtil.JavadocTagType enumConst = JavadocUtil.JavadocTagType.valueOf("ALL");
     assertWithMessage("Invalid enum valueOf result")
         .that(enumConst)
@@ -44,7 +44,7 @@ public class JavadocTagTest {
    * values() is uncovered.
    */
   @Test
-  public void testJavadocTagTypeValues() {
+  void javadocTagTypeValues() {
     final JavadocUtil.JavadocTagType[] enumConstants = JavadocUtil.JavadocTagType.values();
     final JavadocUtil.JavadocTagType[] expected = {
       JavadocUtil.JavadocTagType.BLOCK,
@@ -55,7 +55,7 @@ public class JavadocTagTest {
   }
 
   @Test
-  public void testToString() {
+  void testToString() {
     final JavadocTag javadocTag = new JavadocTag(0, 1, "author", "firstArg");
 
     final String result = javadocTag.toString();
@@ -66,7 +66,7 @@ public class JavadocTagTest {
   }
 
   @Test
-  public void testJavadocTagReferenceImports() {
+  void javadocTagReferenceImports() {
     assertThat(new JavadocTag(0, 0, "see", null).canReferenceImports()).isTrue();
     assertThat(new JavadocTag(0, 0, "link", null).canReferenceImports()).isTrue();
     assertThat(new JavadocTag(0, 0, "value", null).canReferenceImports()).isTrue();
@@ -76,7 +76,7 @@ public class JavadocTagTest {
   }
 
   @Test
-  public void testJavadocTagReferenceImportsInvalid() {
+  void javadocTagReferenceImportsInvalid() {
     assertThat(new JavadocTag(0, 0, "author", null).canReferenceImports()).isFalse();
   }
 }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocTypeCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocTypeCheckTest.java
@@ -30,7 +30,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
+final class JavadocTypeCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -38,7 +38,7 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final JavadocTypeCheck javadocTypeCheck = new JavadocTypeCheck();
     assertWithMessage("JavadocTypeCheck#getRequiredTokens should return empty array by default")
         .that(javadocTypeCheck.getRequiredTokens())
@@ -46,7 +46,7 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final JavadocTypeCheck javadocTypeCheck = new JavadocTypeCheck();
 
     final int[] actual = javadocTypeCheck.getAcceptableTokens();
@@ -62,43 +62,43 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTags() throws Exception {
+  void tags() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocTypeTags.java"), expected);
   }
 
   @Test
-  public void testInner() throws Exception {
+  void inner() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocTypeInner.java"), expected);
   }
 
   @Test
-  public void testStrict() throws Exception {
+  void strict() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocTypePublicOnly.java"), expected);
   }
 
   @Test
-  public void testProtected() throws Exception {
+  void testProtected() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocTypePublicOnly1.java"), expected);
   }
 
   @Test
-  public void testPublic() throws Exception {
+  void testPublic() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocTypeScopeInnerInterfaces.java"), expected);
   }
 
   @Test
-  public void testProtest() throws Exception {
+  void protest() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocTypeScopeInnerInterfaces1.java"), expected);
   }
 
   @Test
-  public void testPkg() throws Exception {
+  void pkg() throws Exception {
     final String[] expected = {
       "53:5: " + getCheckMessage(MSG_MISSING_TAG, "@param <T>"),
     };
@@ -106,13 +106,13 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEclipse() throws Exception {
+  void eclipse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocTypeScopeInnerClasses1.java"), expected);
   }
 
   @Test
-  public void testAuthorRequired() throws Exception {
+  void authorRequired() throws Exception {
     final String[] expected = {
       "23:1: " + getCheckMessage(MSG_MISSING_TAG, "@author"),
     };
@@ -120,7 +120,7 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAuthorRegularEx() throws Exception {
+  void authorRegularEx() throws Exception {
     final String[] expected = {
       "31:1: " + getCheckMessage(MSG_MISSING_TAG, "@author"),
       "67:1: " + getCheckMessage(MSG_MISSING_TAG, "@author"),
@@ -130,7 +130,7 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAuthorRegularExError() throws Exception {
+  void authorRegularExError() throws Exception {
     final String[] expected = {
       "22:1: " + getCheckMessage(MSG_TAG_FORMAT, "@author", "ABC"),
       "31:1: " + getCheckMessage(MSG_MISSING_TAG, "@author"),
@@ -146,7 +146,7 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testVersionRequired() throws Exception {
+  void versionRequired() throws Exception {
     final String[] expected = {
       "23:1: " + getCheckMessage(MSG_MISSING_TAG, "@version"),
     };
@@ -154,7 +154,7 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testVersionRegularEx() throws Exception {
+  void versionRegularEx() throws Exception {
     final String[] expected = {
       "31:1: " + getCheckMessage(MSG_MISSING_TAG, "@version"),
       "67:1: " + getCheckMessage(MSG_MISSING_TAG, "@version"),
@@ -164,7 +164,7 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testVersionRegularExError() throws Exception {
+  void versionRegularExError() throws Exception {
     final String[] expected = {
       "22:1: " + getCheckMessage(MSG_TAG_FORMAT, "@version", "\\$Revision.*\\$"),
       "31:1: " + getCheckMessage(MSG_MISSING_TAG, "@version"),
@@ -183,7 +183,7 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testScopes() throws Exception {
+  void scopes() throws Exception {
     final String[] expected = {
       "18:1: " + getCheckMessage(MSG_MISSING_TAG, "@param <T>"),
       "137:5: " + getCheckMessage(MSG_MISSING_TAG, "@param <T>"),
@@ -192,13 +192,13 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLimitViolationsBySpecifyingTokens() throws Exception {
+  void limitViolationsBySpecifyingTokens() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocTypeNoJavadocOnInterface.java"), expected);
   }
 
   @Test
-  public void testScopes2() throws Exception {
+  void scopes2() throws Exception {
     final String[] expected = {
       "18:1: " + getCheckMessage(MSG_MISSING_TAG, "@param <T>"),
     };
@@ -206,7 +206,7 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExcludeScope() throws Exception {
+  void excludeScope() throws Exception {
     final String[] expected = {
       "137:5: " + getCheckMessage(MSG_MISSING_TAG, "@param <T>"),
     };
@@ -214,7 +214,7 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTypeParameters() throws Exception {
+  void typeParameters() throws Exception {
     final String[] expected = {
       "21:4: " + getCheckMessage(MSG_UNUSED_TAG, "@param", "<D123>"),
       "25:1: " + getCheckMessage(MSG_MISSING_TAG, "@param <C456>"),
@@ -226,7 +226,7 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowMissingTypeParameters() throws Exception {
+  void allowMissingTypeParameters() throws Exception {
     final String[] expected = {
       "21:4: " + getCheckMessage(MSG_UNUSED_TAG, "@param", "<D123>"),
       "58:8: " + getCheckMessage(MSG_UNUSED_TAG, "@param", "<C>"),
@@ -236,7 +236,7 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDontAllowUnusedParameterTag() throws Exception {
+  void dontAllowUnusedParameterTag() throws Exception {
     final String[] expected = {
       "20:4: " + getCheckMessage(MSG_UNUSED_TAG, "@param", "BAD"),
       "21:4: " + getCheckMessage(MSG_UNUSED_TAG, "@param", "<BAD>"),
@@ -246,7 +246,7 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBadTag() throws Exception {
+  void badTag() throws Exception {
     final String[] expected = {
       "19:4: " + getCheckMessage(MSG_UNKNOWN_TAG, "mytag"),
     };
@@ -254,33 +254,33 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBadTagSuppress() throws Exception {
+  void badTagSuppress() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocTypeBadTag_1.java"), expected);
   }
 
   @Test
-  public void testAllowedAnnotationsDefault() throws Exception {
+  void allowedAnnotationsDefault() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocTypeAllowedAnnotations.java"), expected);
   }
 
   @Test
-  public void testAllowedAnnotationsWithFullyQualifiedName() throws Exception {
+  void allowedAnnotationsWithFullyQualifiedName() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocTypeAllowedAnnotations_1.java"), expected);
   }
 
   @Test
-  public void testAllowedAnnotationsAllowed() throws Exception {
+  void allowedAnnotationsAllowed() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocTypeAllowedAnnotations_2.java"), expected);
   }
 
   @Test
-  public void testAllowedAnnotationsNotAllowed() throws Exception {
+  void allowedAnnotationsNotAllowed() throws Exception {
 
     final String[] expected = {
       "38:1: " + getCheckMessage(MSG_MISSING_TAG, "@param <T>"),
@@ -289,7 +289,7 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocTypeRecords() throws Exception {
+  void javadocTypeRecords() throws Exception {
     final String[] expected = {
       "24:1: " + getCheckMessage(MSG_MISSING_TAG, "@author"),
       "33:1: " + getCheckMessage(MSG_MISSING_TAG, "@author"),
@@ -301,7 +301,7 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocTypeRecordComponents() throws Exception {
+  void javadocTypeRecordComponents() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -310,7 +310,7 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocTypeRecordComponents2() throws Exception {
+  void javadocTypeRecordComponents2() throws Exception {
 
     final String[] expected = {
       "44:1: " + getCheckMessage(MSG_MISSING_TAG, "@param <X>"),
@@ -331,7 +331,7 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocTypeInterfaceMemberScopeIsPublic() throws Exception {
+  void javadocTypeInterfaceMemberScopeIsPublic() throws Exception {
 
     final String[] expected = {
       "19:5: " + getCheckMessage(MSG_UNUSED_TAG, "@param", "<T>"),
@@ -342,7 +342,7 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTrimOptionProperty() throws Exception {
+  void trimOptionProperty() throws Exception {
     final String[] expected = {
       "21:4: " + getCheckMessage(MSG_UNUSED_TAG, "@param", "<D123>"),
     };
@@ -350,13 +350,13 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAuthorFormat() throws Exception {
+  void authorFormat() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocType1.java"), expected);
   }
 
   @Test
-  public void testAuthorFormat2() throws Exception {
+  void authorFormat2() throws Exception {
     final String[] expected = {
       "15:1: " + getCheckMessage(MSG_MISSING_TAG, "@author"),
     };
@@ -364,7 +364,7 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocType() throws Exception {
+  void javadocType() throws Exception {
     final String[] expected = {
       "28:5: " + getCheckMessage(MSG_MISSING_TAG, "@param <T>"),
     };
@@ -372,7 +372,7 @@ public class JavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocType2() throws Exception {
+  void javadocType2() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocType4.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocVariableCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocVariableCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class JavadocVariableCheckTest extends AbstractModuleTestSupport {
+final class JavadocVariableCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class JavadocVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final JavadocVariableCheck javadocVariableCheck = new JavadocVariableCheck();
     final int[] actual = javadocVariableCheck.getRequiredTokens();
     final int[] expected = {
@@ -45,7 +45,7 @@ public class JavadocVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final JavadocVariableCheck javadocVariableCheck = new JavadocVariableCheck();
 
     final int[] actual = javadocVariableCheck.getAcceptableTokens();
@@ -57,7 +57,7 @@ public class JavadocVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "18:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "311:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -68,7 +68,7 @@ public class JavadocVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnother() throws Exception {
+  void another() throws Exception {
     final String[] expected = {
       "23:9: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "30:9: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -78,13 +78,13 @@ public class JavadocVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnother2() throws Exception {
+  void another2() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavadocVariableInner2.java"), expected);
   }
 
   @Test
-  public void testAnother3() throws Exception {
+  void another3() throws Exception {
     final String[] expected = {
       "17:9: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "22:13: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -98,7 +98,7 @@ public class JavadocVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnother4() throws Exception {
+  void another4() throws Exception {
     final String[] expected = {
       "52:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
     };
@@ -106,7 +106,7 @@ public class JavadocVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testScopes() throws Exception {
+  void scopes() throws Exception {
     final String[] expected = {
       "15:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "16:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -150,7 +150,7 @@ public class JavadocVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testScopes2() throws Exception {
+  void scopes2() throws Exception {
     final String[] expected = {
       "15:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "16:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -161,7 +161,7 @@ public class JavadocVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExcludeScope() throws Exception {
+  void excludeScope() throws Exception {
     final String[] expected = {
       "17:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "18:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -201,7 +201,7 @@ public class JavadocVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoredVariableNames() throws Exception {
+  void ignoredVariableNames() throws Exception {
     final String[] expected = {
       "15:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "16:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -244,7 +244,7 @@ public class JavadocVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDoNotIgnoreAnythingWhenIgnoreNamePatternIsEmpty() throws Exception {
+  void doNotIgnoreAnythingWhenIgnoreNamePatternIsEmpty() throws Exception {
     final String[] expected = {
       "15:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "16:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -288,7 +288,7 @@ public class JavadocVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLambdaLocalVariablesDoNotNeedJavadoc() throws Exception {
+  void lambdaLocalVariablesDoNotNeedJavadoc() throws Exception {
     final String[] expected = {
       "16:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
     };
@@ -297,7 +297,7 @@ public class JavadocVariableCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInterfaceMemberScopeIsPublic() throws Exception {
+  void interfaceMemberScopeIsPublic() throws Exception {
     final String[] expected = {
       "18:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "20:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/MissingJavadocMethodCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/MissingJavadocMethodCheckTest.java
@@ -30,7 +30,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.io.File;
 import org.junit.jupiter.api.Test;
 
-public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
+final class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -38,7 +38,7 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final MissingJavadocMethodCheck missingJavadocMethodCheck = new MissingJavadocMethodCheck();
 
     final int[] actual = missingJavadocMethodCheck.getAcceptableTokens();
@@ -53,7 +53,7 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final MissingJavadocMethodCheck missingJavadocMethodCheck = new MissingJavadocMethodCheck();
     final int[] actual = missingJavadocMethodCheck.getRequiredTokens();
     final int[] expected = CommonUtil.EMPTY_INT_ARRAY;
@@ -61,7 +61,7 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void extendAnnotationTest() throws Exception {
+  void extendAnnotationTest() throws Exception {
     final String[] expected = {
       "44:1: " + getCheckMessage(MSG_JAVADOC_MISSING),
     };
@@ -70,7 +70,7 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void newTest() throws Exception {
+  void newTest() throws Exception {
     final String[] expected = {
       "70:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
     };
@@ -78,7 +78,7 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void allowedAnnotationsTest() throws Exception {
+  void allowedAnnotationsTest() throws Exception {
     final String[] expected = {
       "32:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
     };
@@ -87,7 +87,7 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTags() throws Exception {
+  void tags() throws Exception {
     final String[] expected = {
       "23:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "337:9: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -98,7 +98,7 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStrictJavadoc() throws Exception {
+  void strictJavadoc() throws Exception {
     final String[] expected = {
       "24:9: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "30:13: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -117,14 +117,14 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoJavadoc() throws Exception {
+  void noJavadoc() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMissingJavadocMethodPublicOnly2.java"), expected);
   }
 
   // pre 1.4 relaxed mode is roughly equivalent with check=protected
   @Test
-  public void testRelaxedJavadoc() throws Exception {
+  void relaxedJavadoc() throws Exception {
     final String[] expected = {
       "65:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "69:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -135,7 +135,7 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testScopeInnerInterfacesPublic() throws Exception {
+  void scopeInnerInterfacesPublic() throws Exception {
     final String[] expected = {
       "52:9: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "53:9: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -145,7 +145,7 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInterfaceMemberScopeIsPublic() throws Exception {
+  void interfaceMemberScopeIsPublic() throws Exception {
     final String[] expected = {
       "22:9: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "30:9: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -155,7 +155,7 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEnumCtorScopeIsPrivate() throws Exception {
+  void enumCtorScopeIsPrivate() throws Exception {
     final String[] expected = {
       "26:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
     };
@@ -164,13 +164,13 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testScopeAnonInnerPrivate() throws Exception {
+  void scopeAnonInnerPrivate() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMissingJavadocMethodScopeAnonInner.java"), expected);
   }
 
   @Test
-  public void testScopeAnonInnerAnonInner() throws Exception {
+  void scopeAnonInnerAnonInner() throws Exception {
     final String[] expected = {
       "34:9: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "47:13: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -181,7 +181,7 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testScopes() throws Exception {
+  void scopes() throws Exception {
     final String[] expected = {
       "26:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "27:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -225,7 +225,7 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testScopes2() throws Exception {
+  void scopes2() throws Exception {
     final String[] expected = {
       "26:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "27:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -236,7 +236,7 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExcludeScope() throws Exception {
+  void excludeScope() throws Exception {
     final String[] expected = {
       "27:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "29:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -268,14 +268,14 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDoAllowMissingJavadocTagsByDefault() throws Exception {
+  void doAllowMissingJavadocTagsByDefault() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputMissingJavadocMethodMissingJavadocTags.java"), expected);
   }
 
   @Test
-  public void testSetterGetterOff() throws Exception {
+  void setterGetterOff() throws Exception {
     final String[] expected = {
       "20:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "25:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -299,7 +299,7 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSetterGetterOnCheck() throws Exception {
+  void setterGetterOnCheck() throws Exception {
     final String[] expected = {
       "30:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "35:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -320,26 +320,26 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test11684081() throws Exception {
+  void test11684081() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMissingJavadocMethod_01.java"), expected);
   }
 
   @Test
-  public void test11684082() throws Exception {
+  void test11684082() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMissingJavadocMethod_02.java"), expected);
   }
 
   @Test
-  public void testSkipCertainMethods() throws Exception {
+  void skipCertainMethods() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputMissingJavadocMethodIgnoreNameRegex.java"), expected);
   }
 
   @Test
-  public void testNotSkipAnythingWhenSkipRegexDoesNotMatch() throws Exception {
+  void notSkipAnythingWhenSkipRegexDoesNotMatch() throws Exception {
     final String[] expected = {
       "22:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "26:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -350,21 +350,21 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowToSkipOverridden() throws Exception {
+  void allowToSkipOverridden() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputMissingJavadocMethodsNotSkipWritten.java"), expected);
   }
 
   @Test
-  public void testJava8ReceiverParameter() throws Exception {
+  void java8ReceiverParameter() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputMissingJavadocMethodReceiverParameter.java"), expected);
   }
 
   @Test
-  public void testJavadocInMethod() throws Exception {
+  void javadocInMethod() throws Exception {
     final String[] expected = {
       "20:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "22:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -376,7 +376,7 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testConstructor() throws Exception {
+  void constructor() throws Exception {
     final String[] expected = {
       "21:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
     };
@@ -384,14 +384,14 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNotPublicInterfaceMethods() throws Exception {
+  void notPublicInterfaceMethods() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputMissingJavadocMethodInterfacePrivateMethod.java"), expected);
   }
 
   @Test
-  public void testPublicMethods() throws Exception {
+  void publicMethods() throws Exception {
     final String[] expected = {
       "22:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "24:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -403,7 +403,7 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMissingJavadocMethodRecordsAndCompactCtors() throws Exception {
+  void missingJavadocMethodRecordsAndCompactCtors() throws Exception {
     final String[] expected = {
       "22:9: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "27:9: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -417,7 +417,7 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMissingJavadocMethodRecordsAndCompactCtorsMinLineCount() throws Exception {
+  void missingJavadocMethodRecordsAndCompactCtorsMinLineCount() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -427,7 +427,7 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMinLineCount() throws Exception {
+  void minLineCount() throws Exception {
     final String[] expected = {
       "14:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
     };
@@ -435,7 +435,7 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationField() throws Exception {
+  void annotationField() throws Exception {
     final String[] expected = {
       "25:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "27:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -446,7 +446,7 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIsGetterMethod() throws Exception {
+  void isGetterMethod() throws Exception {
     final File testFile = new File(getPath("InputMissingJavadocMethodSetterGetter3.java"));
     final DetailAST notGetterMethod = CheckUtilTest.getNode(testFile, TokenTypes.METHOD_DEF);
     final DetailAST getterMethod = notGetterMethod.getNextSibling().getNextSibling();
@@ -460,7 +460,7 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIsSetterMethod() throws Exception {
+  void isSetterMethod() throws Exception {
     final File testFile = new File(getPath("InputMissingJavadocMethodSetterGetter3.java"));
     final DetailAST firstClassMethod = CheckUtilTest.getNode(testFile, TokenTypes.METHOD_DEF);
     final DetailAST setterMethod =
@@ -476,7 +476,7 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSetterGetterOn() throws Exception {
+  void setterGetterOn() throws Exception {
     final String[] expected = {
       "20:5: " + getCheckMessage(MissingJavadocMethodCheck.class, MSG_JAVADOC_MISSING),
       "24:5: " + getCheckMessage(MissingJavadocMethodCheck.class, MSG_JAVADOC_MISSING),
@@ -486,7 +486,7 @@ public class MissingJavadocMethodCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void missingJavadoc() throws Exception {
+  void missingJavadoc() throws Exception {
     final String[] expected = {
       "13:5: " + getCheckMessage(MissingJavadocMethodCheck.class, MSG_JAVADOC_MISSING),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/MissingJavadocPackageCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/MissingJavadocPackageCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class MissingJavadocPackageCheckTest extends AbstractModuleTestSupport {
+final class MissingJavadocPackageCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,31 +35,31 @@ public class MissingJavadocPackageCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackageJavadocPresent() throws Exception {
+  void packageJavadocPresent() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("package-info.java"), expected);
   }
 
   @Test
-  public void testPackageSingleLineJavadocPresent() throws Exception {
+  void packageSingleLineJavadocPresent() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("singleline/package-info.java"), expected);
   }
 
   @Test
-  public void testPackageJavadocPresentWithAnnotation() throws Exception {
+  void packageJavadocPresentWithAnnotation() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("annotation/package-info.java"), expected);
   }
 
   @Test
-  public void testPackageJavadocPresentWithBlankLines() throws Exception {
+  void packageJavadocPresentWithBlankLines() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("blank/package-info.java"), expected);
   }
 
   @Test
-  public void testPackageJavadocMissing() throws Exception {
+  void packageJavadocMissing() throws Exception {
     final String[] expected = {
       "7:1: " + getCheckMessage(MSG_PKG_JAVADOC_MISSING),
     };
@@ -67,7 +67,7 @@ public class MissingJavadocPackageCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBlockCommentInsteadOfJavadoc() throws Exception {
+  void blockCommentInsteadOfJavadoc() throws Exception {
     final String[] expected = {
       "10:1: " + getCheckMessage(MSG_PKG_JAVADOC_MISSING),
     };
@@ -75,7 +75,7 @@ public class MissingJavadocPackageCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSinglelineCommentInsteadOfJavadoc() throws Exception {
+  void singlelineCommentInsteadOfJavadoc() throws Exception {
     final String[] expected = {
       "8:1: " + getCheckMessage(MSG_PKG_JAVADOC_MISSING),
     };
@@ -83,7 +83,7 @@ public class MissingJavadocPackageCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSinglelineCommentInsteadOfJavadoc2() throws Exception {
+  void singlelineCommentInsteadOfJavadoc2() throws Exception {
     final String[] expected = {
       "8:1: " + getCheckMessage(MSG_PKG_JAVADOC_MISSING),
     };
@@ -91,7 +91,7 @@ public class MissingJavadocPackageCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackageJavadocMissingWithAnnotation() throws Exception {
+  void packageJavadocMissingWithAnnotation() throws Exception {
     final String[] expected = {
       "8:1: " + getCheckMessage(MSG_PKG_JAVADOC_MISSING),
     };
@@ -99,7 +99,7 @@ public class MissingJavadocPackageCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackageJavadocMissingWithAnnotationAndBlockComment() throws Exception {
+  void packageJavadocMissingWithAnnotationAndBlockComment() throws Exception {
     final String[] expected = {
       "12:1: " + getCheckMessage(MSG_PKG_JAVADOC_MISSING),
     };
@@ -108,7 +108,7 @@ public class MissingJavadocPackageCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackageJavadocMissingDetachedJavadoc() throws Exception {
+  void packageJavadocMissingDetachedJavadoc() throws Exception {
     final String[] expected = {
       "11:1: " + getCheckMessage(MSG_PKG_JAVADOC_MISSING),
     };
@@ -116,13 +116,13 @@ public class MissingJavadocPackageCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackageJavadocPresentWithHeader() throws Exception {
+  void packageJavadocPresentWithHeader() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("header/package-info.java"), expected);
   }
 
   @Test
-  public void testPackageJavadocMissingWithBlankLines() throws Exception {
+  void packageJavadocMissingWithBlankLines() throws Exception {
     final String[] expected = {
       "8:1: " + getCheckMessage(MSG_PKG_JAVADOC_MISSING),
     };
@@ -130,14 +130,14 @@ public class MissingJavadocPackageCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNotPackageInfo() throws Exception {
+  void notPackageInfo() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyFilterWithInlineConfigParser(
         getPath("InputMissingJavadocPackageNotPackageInfo-package-info.java"), expected);
   }
 
   @Test
-  public void testTokensAreCorrect() {
+  void tokensAreCorrect() {
     final MissingJavadocPackageCheck check = new MissingJavadocPackageCheck();
     final int[] expected = {
       TokenTypes.PACKAGE_DEF,
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/MissingJavadocTypeCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/MissingJavadocTypeCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
+final class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final MissingJavadocTypeCheck missingJavadocTypeCheck = new MissingJavadocTypeCheck();
     assertWithMessage(
             "MissingJavadocTypeCheck#getRequiredTokens should return empty array by default")
@@ -44,7 +44,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final MissingJavadocTypeCheck missingJavadocTypeCheck = new MissingJavadocTypeCheck();
 
     final int[] actual = missingJavadocTypeCheck.getAcceptableTokens();
@@ -60,7 +60,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTagsOne() throws Exception {
+  void tagsOne() throws Exception {
     final String[] expected = {
       "14:1: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "44:1: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -70,7 +70,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTagsTwo() throws Exception {
+  void tagsTwo() throws Exception {
     final String[] expected = {
       "20:1: " + getCheckMessage(MSG_JAVADOC_MISSING),
     };
@@ -78,7 +78,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTagsThree() throws Exception {
+  void tagsThree() throws Exception {
     final String[] expected = {
       "20:1: " + getCheckMessage(MSG_JAVADOC_MISSING),
     };
@@ -86,7 +86,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTagsFour() throws Exception {
+  void tagsFour() throws Exception {
     final String[] expected = {
       "20:1: " + getCheckMessage(MSG_JAVADOC_MISSING),
     };
@@ -94,7 +94,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInner() throws Exception {
+  void inner() throws Exception {
     final String[] expected = {
       "19:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "26:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -104,7 +104,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStrict() throws Exception {
+  void strict() throws Exception {
     final String[] expected = {
       "13:1: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "15:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -115,7 +115,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testProtected() throws Exception {
+  void testProtected() throws Exception {
     final String[] expected = {
       "13:1: " + getCheckMessage(MSG_JAVADOC_MISSING),
     };
@@ -123,7 +123,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPublic() throws Exception {
+  void testPublic() throws Exception {
     final String[] expected = {
       "13:1: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "44:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -133,7 +133,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testProtest() throws Exception {
+  void protest() throws Exception {
     final String[] expected = {
       "13:1: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "35:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -145,7 +145,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPkg() throws Exception {
+  void pkg() throws Exception {
     final String[] expected = {
       "22:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "24:9: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -156,7 +156,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEclipse() throws Exception {
+  void eclipse() throws Exception {
     final String[] expected = {
       "22:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
     };
@@ -165,7 +165,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testScopesOne() throws Exception {
+  void scopesOne() throws Exception {
     final String[] expected = {
       "13:1: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "25:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -176,7 +176,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testScopesTwo() throws Exception {
+  void scopesTwo() throws Exception {
     final String[] expected = {
       "13:1: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "15:1: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -190,7 +190,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLimitViolationsBySpecifyingTokens() throws Exception {
+  void limitViolationsBySpecifyingTokens() throws Exception {
     final String[] expected = {
       "15:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
     };
@@ -199,7 +199,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testScopes2() throws Exception {
+  void scopes2() throws Exception {
     final String[] expected = {
       "13:1: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "25:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -208,7 +208,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExcludeScope() throws Exception {
+  void excludeScope() throws Exception {
     final String[] expected = {
       "37:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "49:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -223,14 +223,14 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDontAllowUnusedParameterTag() throws Exception {
+  void dontAllowUnusedParameterTag() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputMissingJavadocTypeUnusedParamInJavadocForClass.java"), expected);
   }
 
   @Test
-  public void testSkipAnnotationsDefault() throws Exception {
+  void skipAnnotationsDefault() throws Exception {
 
     final String[] expected = {
       "13:1: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -241,7 +241,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSkipAnnotationsWithFullyQualifiedName() throws Exception {
+  void skipAnnotationsWithFullyQualifiedName() throws Exception {
     final String[] expected = {
       "13:1: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "17:1: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -251,14 +251,14 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSkipAnnotationsAllowed() throws Exception {
+  void skipAnnotationsAllowed() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMissingJavadocTypeSkipAnnotations3.java"), expected);
   }
 
   @Test
-  public void testSkipAnnotationsNotAllowed() throws Exception {
+  void skipAnnotationsNotAllowed() throws Exception {
 
     final String[] expected = {
       "13:1: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -269,7 +269,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMissingJavadocTypeCheckRecords() throws Exception {
+  void missingJavadocTypeCheckRecords() throws Exception {
 
     final String[] expected = {
       "14:1: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -285,7 +285,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInterfaceMemberScopeIsPublic() throws Exception {
+  void interfaceMemberScopeIsPublic() throws Exception {
 
     final String[] expected = {
       "13:1: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -297,7 +297,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQualifiedAnnotation1() throws Exception {
+  void qualifiedAnnotation1() throws Exception {
     final String[] expected = {
       "16:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "20:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -308,7 +308,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQualifiedAnnotation2() throws Exception {
+  void qualifiedAnnotation2() throws Exception {
     final String[] expected = {
       "20:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "23:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -318,7 +318,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQualifiedAnnotation3() throws Exception {
+  void qualifiedAnnotation3() throws Exception {
     final String[] expected = {
       "16:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "22:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -328,7 +328,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQualifiedAnnotation4() throws Exception {
+  void qualifiedAnnotation4() throws Exception {
     final String[] expected = {
       "17:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "21:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -338,14 +338,14 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQualifiedAnnotation5() throws Exception {
+  void qualifiedAnnotation5() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputMissingJavadocTypeQualifiedAnnotation5.java"), expected);
   }
 
   @Test
-  public void testMultipleQualifiedAnnotation() throws Exception {
+  void multipleQualifiedAnnotation() throws Exception {
     final String[] expected = {
       "29:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "38:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
@@ -355,7 +355,7 @@ public class MissingJavadocTypeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQualifiedAnnotationWithParameters() throws Exception {
+  void qualifiedAnnotationWithParameters() throws Exception {
     final String[] expected = {
       "33:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
       "37:5: " + getCheckMessage(MSG_JAVADOC_MISSING),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/NonEmptyAtclauseDescriptionCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/NonEmptyAtclauseDescriptionCheckTest.java
@@ -31,7 +31,7 @@ import de.thetaphi.forbiddenapis.SuppressForbidden;
 import java.nio.charset.CodingErrorAction;
 import org.junit.jupiter.api.Test;
 
-public class NonEmptyAtclauseDescriptionCheckTest extends AbstractModuleTestSupport {
+final class NonEmptyAtclauseDescriptionCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -39,7 +39,7 @@ public class NonEmptyAtclauseDescriptionCheckTest extends AbstractModuleTestSupp
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final NonEmptyAtclauseDescriptionCheck checkObj = new NonEmptyAtclauseDescriptionCheck();
     final int[] expected = {TokenTypes.BLOCK_COMMENT_BEGIN};
     assertWithMessage("Default acceptable tokens are invalid")
@@ -48,7 +48,7 @@ public class NonEmptyAtclauseDescriptionCheckTest extends AbstractModuleTestSupp
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final NonEmptyAtclauseDescriptionCheck checkObj = new NonEmptyAtclauseDescriptionCheck();
     final int[] expected = {TokenTypes.BLOCK_COMMENT_BEGIN};
     assertWithMessage("Default required tokens are invalid")
@@ -57,7 +57,7 @@ public class NonEmptyAtclauseDescriptionCheckTest extends AbstractModuleTestSupp
   }
 
   @Test
-  public void testCheckOne() throws Exception {
+  void checkOne() throws Exception {
     final String[] expected = {
       // this is a case with description that is sequences of spaces
       "37: " + getCheckMessage(MSG_KEY),
@@ -82,7 +82,7 @@ public class NonEmptyAtclauseDescriptionCheckTest extends AbstractModuleTestSupp
   }
 
   @Test
-  public void testCheckTwo() throws Exception {
+  void checkTwo() throws Exception {
     final String[] expected = {
       "16: " + getCheckMessage(MSG_KEY),
       "17: " + getCheckMessage(MSG_KEY),
@@ -107,7 +107,7 @@ public class NonEmptyAtclauseDescriptionCheckTest extends AbstractModuleTestSupp
    */
   @SuppressForbidden
   @Test
-  public void testDecoderOnMalformedInput() throws Exception {
+  void decoderOnMalformedInput() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     final DefaultConfiguration checkConfig =
         createModuleConfig(NonEmptyAtclauseDescriptionCheck.class);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/RequireEmptyLineBeforeBlockTagGroupCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/RequireEmptyLineBeforeBlockTagGroupCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class RequireEmptyLineBeforeBlockTagGroupCheckTest extends AbstractModuleTestSupport {
+final class RequireEmptyLineBeforeBlockTagGroupCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -36,7 +36,7 @@ public class RequireEmptyLineBeforeBlockTagGroupCheckTest extends AbstractModule
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final RequireEmptyLineBeforeBlockTagGroupCheck checkObj =
         new RequireEmptyLineBeforeBlockTagGroupCheck();
     final int[] expected = {TokenTypes.BLOCK_COMMENT_BEGIN};
@@ -46,7 +46,7 @@ public class RequireEmptyLineBeforeBlockTagGroupCheckTest extends AbstractModule
   }
 
   @Test
-  public void testCorrect() throws Exception {
+  void correct() throws Exception {
     createModuleConfig(RequireEmptyLineBeforeBlockTagGroupCheck.class);
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -55,7 +55,7 @@ public class RequireEmptyLineBeforeBlockTagGroupCheckTest extends AbstractModule
   }
 
   @Test
-  public void testIncorrect() throws Exception {
+  void incorrect() throws Exception {
     final String[] expected = {
       "14: " + getCheckMessage(MSG_JAVADOC_TAG_LINE_BEFORE, "@since"),
       "20: " + getCheckMessage(MSG_JAVADOC_TAG_LINE_BEFORE, "@param"),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/SingleLineJavadocCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/SingleLineJavadocCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class SingleLineJavadocCheckTest extends AbstractModuleTestSupport {
+final class SingleLineJavadocCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class SingleLineJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAcceptableTokens() {
+  void acceptableTokens() {
     final SingleLineJavadocCheck checkObj = new SingleLineJavadocCheck();
     final int[] expected = {TokenTypes.BLOCK_COMMENT_BEGIN};
     assertWithMessage("Default acceptable tokens are invalid")
@@ -43,7 +43,7 @@ public class SingleLineJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final SingleLineJavadocCheck checkObj = new SingleLineJavadocCheck();
     final int[] expected = {TokenTypes.BLOCK_COMMENT_BEGIN};
     assertWithMessage("Default required tokens are invalid")
@@ -52,7 +52,7 @@ public class SingleLineJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void simpleTest() throws Exception {
+  void simpleTest() throws Exception {
     final String[] expected = {
       "22: " + getCheckMessage(MSG_KEY),
       "38: " + getCheckMessage(MSG_KEY),
@@ -64,7 +64,7 @@ public class SingleLineJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoredTags() throws Exception {
+  void ignoredTags() throws Exception {
     final String[] expected = {
       "14: " + getCheckMessage(MSG_KEY),
       "44: " + getCheckMessage(MSG_KEY),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/SummaryJavadocCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/SummaryJavadocCheckTest.java
@@ -30,7 +30,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class SummaryJavadocCheckTest extends AbstractModuleTestSupport {
+final class SummaryJavadocCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -38,7 +38,7 @@ public class SummaryJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final SummaryJavadocCheck checkObj = new SummaryJavadocCheck();
     final int[] expected = {TokenTypes.BLOCK_COMMENT_BEGIN};
     assertWithMessage("Default required tokens are invalid")
@@ -47,14 +47,14 @@ public class SummaryJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCorrect() throws Exception {
+  void correct() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputSummaryJavadocCorrect.java"), expected);
   }
 
   @Test
-  public void testInlineCorrect() throws Exception {
+  void inlineCorrect() throws Exception {
     final String[] expected = {
       "112: " + getCheckMessage(MSG_SUMMARY_FIRST_SENTENCE),
     };
@@ -63,7 +63,7 @@ public class SummaryJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIncorrect() throws Exception {
+  void incorrect() throws Exception {
     final String[] expected = {
       "24: " + getCheckMessage(MSG_SUMMARY_JAVADOC_MISSING),
       "42: " + getCheckMessage(MSG_SUMMARY_JAVADOC_MISSING),
@@ -85,7 +85,7 @@ public class SummaryJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInlineForbidden() throws Exception {
+  void inlineForbidden() throws Exception {
     final String[] expected = {
       "26: " + getCheckMessage(MSG_SUMMARY_MISSING_PERIOD),
       "31: " + getCheckMessage(MSG_SUMMARY_MISSING_PERIOD),
@@ -103,7 +103,7 @@ public class SummaryJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPeriod() throws Exception {
+  void period() throws Exception {
     final String[] expected = {
       "14: " + getCheckMessage(MSG_SUMMARY_FIRST_SENTENCE),
       "19: " + getCheckMessage(MSG_SUMMARY_FIRST_SENTENCE),
@@ -114,14 +114,14 @@ public class SummaryJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoPeriod() throws Exception {
+  void noPeriod() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputSummaryJavadocNoPeriod.java"), expected);
   }
 
   @Test
-  public void testDefaultConfiguration() throws Exception {
+  void defaultConfiguration() throws Exception {
     final String[] expected = {
       "23: " + getCheckMessage(MSG_SUMMARY_JAVADOC_MISSING),
       "41: " + getCheckMessage(MSG_SUMMARY_JAVADOC_MISSING),
@@ -142,7 +142,7 @@ public class SummaryJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIncorrectUsageOfSummaryTag() throws Exception {
+  void incorrectUsageOfSummaryTag() throws Exception {
     final String[] expected = {
       "34: " + getCheckMessage(MSG_SUMMARY_MISSING_PERIOD),
       "41: " + getCheckMessage(MSG_SUMMARY_JAVADOC_MISSING),
@@ -159,7 +159,7 @@ public class SummaryJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInlineDefaultConfiguration() throws Exception {
+  void inlineDefaultConfiguration() throws Exception {
     final String[] expected = {
       "22: " + getCheckMessage(MSG_SUMMARY_MISSING_PERIOD),
       "26: " + getCheckMessage(MSG_SUMMARY_MISSING_PERIOD),
@@ -181,7 +181,7 @@ public class SummaryJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInlineReturn() throws Exception {
+  void inlineReturn() throws Exception {
     final String[] expected = {
       "74: " + getCheckMessage(MSG_SUMMARY_JAVADOC_MISSING),
     };
@@ -190,7 +190,7 @@ public class SummaryJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInlineReturn2() throws Exception {
+  void inlineReturn2() throws Exception {
     final String[] expected = {
       "15: " + getCheckMessage(MSG_SUMMARY_JAVADOC_MISSING),
     };
@@ -199,7 +199,7 @@ public class SummaryJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInlineReturnForbidden() throws Exception {
+  void inlineReturnForbidden() throws Exception {
     final String[] expected = {
       "14: " + getCheckMessage(MSG_SUMMARY_JAVADOC),
       "21: " + getCheckMessage(MSG_SUMMARY_JAVADOC),
@@ -211,7 +211,7 @@ public class SummaryJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPeriodAtEnd() throws Exception {
+  void periodAtEnd() throws Exception {
     final String[] expected = {
       "19: " + getCheckMessage(MSG_SUMMARY_JAVADOC_MISSING),
       "26: " + getCheckMessage(MSG_SUMMARY_JAVADOC_MISSING),
@@ -224,7 +224,7 @@ public class SummaryJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHtmlFormatSummary() throws Exception {
+  void htmlFormatSummary() throws Exception {
     final String[] expected = {
       "22: " + getCheckMessage(MSG_SUMMARY_MISSING_PERIOD),
       "36: " + getCheckMessage(MSG_SUMMARY_JAVADOC_MISSING),
@@ -235,7 +235,7 @@ public class SummaryJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackageInfo() throws Exception {
+  void packageInfo() throws Exception {
     final String[] expected = {
       "10: " + getCheckMessage(MSG_SUMMARY_JAVADOC_MISSING),
     };
@@ -244,7 +244,7 @@ public class SummaryJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackageInfoWithAnnotation() throws Exception {
+  void packageInfoWithAnnotation() throws Exception {
     final String[] expected = {
       "10: " + getCheckMessage(MSG_SUMMARY_JAVADOC_MISSING),
     };
@@ -253,7 +253,7 @@ public class SummaryJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testForbidden() throws Exception {
+  void forbidden() throws Exception {
     final String[] expected = {
       "14: " + getCheckMessage(MSG_SUMMARY_JAVADOC),
     };
@@ -263,14 +263,14 @@ public class SummaryJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyPeriod() throws Exception {
+  void emptyPeriod() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputSummaryJavadocEmptyPeriod.java"), expected);
   }
 
   @Test
-  public void testForbidden3() throws Exception {
+  void forbidden3() throws Exception {
     final String[] expected = {
       "14: " + getCheckMessage(MSG_SUMMARY_JAVADOC),
     };
@@ -280,7 +280,7 @@ public class SummaryJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testForbidden2() throws Exception {
+  void forbidden2() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -288,14 +288,14 @@ public class SummaryJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSummaryJavaDoc() throws Exception {
+  void summaryJavaDoc() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputSummaryJavadoc1.java"), expected);
   }
 
   @Test
-  public void testSummaryJavaDoc2() throws Exception {
+  void summaryJavaDoc2() throws Exception {
     final String[] expected = {
       "15: " + getCheckMessage(MSG_SUMMARY_JAVADOC),
     };
@@ -304,7 +304,7 @@ public class SummaryJavadocCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInheritDoc() throws Exception {
+  void inheritDoc() throws Exception {
     final String[] expected = {
       "14: " + getCheckMessage(MSG_SUMMARY_FIRST_SENTENCE),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/WriteTagCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/WriteTagCheckTest.java
@@ -23,6 +23,7 @@ import static com.google.common.truth.Truth.assertWithMessage;
 import static com.puppycrawl.tools.checkstyle.checks.javadoc.WriteTagCheck.MSG_MISSING_TAG;
 import static com.puppycrawl.tools.checkstyle.checks.javadoc.WriteTagCheck.MSG_TAG_FORMAT;
 import static com.puppycrawl.tools.checkstyle.checks.javadoc.WriteTagCheck.MSG_WRITE_TAG;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.Checker;
@@ -31,14 +32,13 @@ import java.io.ByteArrayInputStream;
 import java.io.File;
 import java.io.InputStreamReader;
 import java.io.LineNumberReader;
-import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
 /** Unit test for WriteTagCheck. */
-public class WriteTagCheckTest extends AbstractModuleTestSupport {
+final class WriteTagCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -46,13 +46,13 @@ public class WriteTagCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultSettings() throws Exception {
+  void defaultSettings() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputWriteTagDefault.java"), expected);
   }
 
   @Test
-  public void testTag() throws Exception {
+  void tag() throws Exception {
     final String[] expected = {
       "15: " + getCheckMessage(MSG_WRITE_TAG, "@author", "Daniel Grenner"),
     };
@@ -60,7 +60,7 @@ public class WriteTagCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMissingFormat() throws Exception {
+  void missingFormat() throws Exception {
     final String[] expected = {
       "15: " + getCheckMessage(MSG_WRITE_TAG, "@author", "Daniel Grenner"),
     };
@@ -68,7 +68,7 @@ public class WriteTagCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTagIncomplete() throws Exception {
+  void tagIncomplete() throws Exception {
     final String[] expected = {
       "16: " + getCheckMessage(MSG_WRITE_TAG, "@incomplete", "This class needs more code..."),
     };
@@ -76,7 +76,7 @@ public class WriteTagCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDoubleTag() throws Exception {
+  void doubleTag() throws Exception {
     final String[] expected = {
       "18: " + getCheckMessage(MSG_WRITE_TAG, "@doubletag", "first text"),
       "19: " + getCheckMessage(MSG_WRITE_TAG, "@doubletag", "second text"),
@@ -85,7 +85,7 @@ public class WriteTagCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyTag() throws Exception {
+  void emptyTag() throws Exception {
     final String[] expected = {
       "19: " + getCheckMessage(MSG_WRITE_TAG, "@emptytag", ""),
     };
@@ -93,7 +93,7 @@ public class WriteTagCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMissingTag() throws Exception {
+  void missingTag() throws Exception {
     final String[] expected = {
       "20: " + getCheckMessage(MSG_MISSING_TAG, "@missingtag"),
     };
@@ -101,7 +101,7 @@ public class WriteTagCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMethod() throws Exception {
+  void method() throws Exception {
     final String[] expected = {
       "24: " + getCheckMessage(MSG_WRITE_TAG, "@todo", "Add a constructor comment"),
       "36: " + getCheckMessage(MSG_WRITE_TAG, "@todo", "Add a comment"),
@@ -110,7 +110,7 @@ public class WriteTagCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSeverity() throws Exception {
+  void severity() throws Exception {
     final String[] expected = {
       "16: " + getCheckMessage(MSG_WRITE_TAG, "@author", "Daniel Grenner"),
     };
@@ -118,19 +118,19 @@ public class WriteTagCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreMissing() throws Exception {
+  void ignoreMissing() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputWriteTagIgnore.java"), expected);
   }
 
   @Test
-  public void testRegularEx() throws Exception {
+  void regularEx() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputWriteTagRegularExpression.java"), expected);
   }
 
   @Test
-  public void testRegularExError() throws Exception {
+  void regularExError() throws Exception {
     final String[] expected = {
       "15: " + getCheckMessage(MSG_TAG_FORMAT, "@author", "ABC"),
     };
@@ -138,7 +138,7 @@ public class WriteTagCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEnumsAndAnnotations() throws Exception {
+  void enumsAndAnnotations() throws Exception {
     final String[] expected = {
       "16: " + getCheckMessage(MSG_WRITE_TAG, "@incomplete", "This enum needs more code..."),
       "21: "
@@ -152,7 +152,7 @@ public class WriteTagCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoJavadocs() throws Exception {
+  void noJavadocs() throws Exception {
     final String[] expected = {
       "13: " + getCheckMessage(MSG_MISSING_TAG, "null"),
     };
@@ -160,7 +160,7 @@ public class WriteTagCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWriteTagRecordsAndCompactCtors() throws Exception {
+  void writeTagRecordsAndCompactCtors() throws Exception {
     final String[] expected = {
       "15: " + getCheckMessage(MSG_MISSING_TAG, "@incomplete"),
       "19: " + getCheckMessage(MSG_TAG_FORMAT, "@incomplete", "\\S"),
@@ -196,8 +196,7 @@ public class WriteTagCheckTest extends AbstractModuleTestSupport {
 
     // process each of the lines
     try (ByteArrayInputStream localStream = new ByteArrayInputStream(getStream().toByteArray());
-        LineNumberReader lnr =
-            new LineNumberReader(new InputStreamReader(localStream, StandardCharsets.UTF_8))) {
+        LineNumberReader lnr = new LineNumberReader(new InputStreamReader(localStream, UTF_8))) {
       for (int i = 0; i < expected.length; i++) {
         final String expectedResult = messageFileName + ":" + expected[i];
         final String actual = lnr.readLine();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/utils/BlockTagUtilTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/utils/BlockTagUtilTest.java
@@ -25,17 +25,17 @@ import com.puppycrawl.tools.checkstyle.internal.utils.TestUtil;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class BlockTagUtilTest {
+final class BlockTagUtilTest {
 
   @Test
-  public void testHasPrivateConstructor() throws Exception {
+  void hasPrivateConstructor() throws Exception {
     assertWithMessage("Constructor is not private")
         .that(TestUtil.isUtilsClassHasPrivateConstructor(BlockTagUtil.class))
         .isTrue();
   }
 
   @Test
-  public void testExtractBlockTags() {
+  void extractBlockTags() {
     final String[] text = {
       "/** @foo abc ", " * @bar def  ", "   @baz ghi  ", " * @qux jkl", " */",
     };
@@ -57,7 +57,7 @@ public class BlockTagUtilTest {
   }
 
   @Test
-  public void testVersionStringFormat() {
+  void versionStringFormat() {
     final String[] text = {
       "/** ", " * @version 1.0", " */",
     };
@@ -68,7 +68,7 @@ public class BlockTagUtilTest {
   }
 
   @Test
-  public void testOddVersionString() {
+  void oddVersionString() {
     final String[] text = {"/**", " * Foo", " * @version 1.0 */"};
 
     final List<TagInfo> tags = BlockTagUtil.extractBlockTags(text);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/utils/InlineTagUtilTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/javadoc/utils/InlineTagUtilTest.java
@@ -25,17 +25,17 @@ import com.puppycrawl.tools.checkstyle.internal.utils.TestUtil;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class InlineTagUtilTest {
+final class InlineTagUtilTest {
 
   @Test
-  public void testHasPrivateConstructor() throws Exception {
+  void hasPrivateConstructor() throws Exception {
     assertWithMessage("Constructor is not private")
         .that(TestUtil.isUtilsClassHasPrivateConstructor(InlineTagUtil.class))
         .isTrue();
   }
 
   @Test
-  public void testExtractInlineTags() {
+  void testExtractInlineTags() {
     final String[] text = {
       "/** @see elsewhere ",
       " * {@link List }, {@link List link text }",
@@ -54,7 +54,7 @@ public class InlineTagUtilTest {
   }
 
   @Test
-  public void testMultiLineLinkTag() {
+  void multiLineLinkTag() {
     final String[] text = {"/**", " * {@link foo", " *        bar baz}", " */"};
 
     final List<TagInfo> tags = InlineTagUtil.extractInlineTags(text);
@@ -64,7 +64,7 @@ public class InlineTagUtilTest {
   }
 
   @Test
-  public void testCollapseWhitespace() {
+  void collapseWhitespace() {
     final String[] text = {"/**", " * {@code     foo\t\t   bar   baz\t    }", " */"};
 
     final List<TagInfo> tags = InlineTagUtil.extractInlineTags(text);
@@ -74,7 +74,7 @@ public class InlineTagUtilTest {
   }
 
   @Test
-  public void extractInlineTags() {
+  void extractInlineTags() {
     final String[] source = {
       "  {@link foo}",
     };
@@ -88,7 +88,7 @@ public class InlineTagUtilTest {
   }
 
   @Test
-  public void testBadInputExtractInlineTagsLineFeed() {
+  void badInputExtractInlineTagsLineFeed() {
     try {
       InlineTagUtil.extractInlineTags("abc\ndef");
       assertWithMessage("IllegalArgumentException expected").fail();
@@ -98,7 +98,7 @@ public class InlineTagUtilTest {
   }
 
   @Test
-  public void testBadInputExtractInlineTagsCarriageReturn() {
+  void badInputExtractInlineTagsCarriageReturn() {
     try {
       InlineTagUtil.extractInlineTags("abc\rdef");
       assertWithMessage("IllegalArgumentException expected").fail();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/metrics/BooleanExpressionComplexityCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/metrics/BooleanExpressionComplexityCheckTest.java
@@ -29,7 +29,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.antlr.v4.runtime.CommonToken;
 import org.junit.jupiter.api.Test;
 
-public class BooleanExpressionComplexityCheckTest extends AbstractModuleTestSupport {
+final class BooleanExpressionComplexityCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -37,7 +37,7 @@ public class BooleanExpressionComplexityCheckTest extends AbstractModuleTestSupp
   }
 
   @Test
-  public void test() throws Exception {
+  void test() throws Exception {
 
     final String[] expected = {
       "21:9: " + getCheckMessage(MSG_KEY, 4, 3),
@@ -51,7 +51,7 @@ public class BooleanExpressionComplexityCheckTest extends AbstractModuleTestSupp
   }
 
   @Test
-  public void testNoBitwise() throws Exception {
+  void noBitwise() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -59,7 +59,7 @@ public class BooleanExpressionComplexityCheckTest extends AbstractModuleTestSupp
   }
 
   @Test
-  public void testNullPointerException() throws Exception {
+  void nullPointerException() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -67,7 +67,7 @@ public class BooleanExpressionComplexityCheckTest extends AbstractModuleTestSupp
   }
 
   @Test
-  public void testWrongToken() {
+  void wrongToken() {
     final BooleanExpressionComplexityCheck booleanExpressionComplexityCheckObj =
         new BooleanExpressionComplexityCheck();
     final DetailAstImpl ast = new DetailAstImpl();
@@ -83,7 +83,7 @@ public class BooleanExpressionComplexityCheckTest extends AbstractModuleTestSupp
   }
 
   @Test
-  public void testSmall() throws Exception {
+  void small() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -91,7 +91,7 @@ public class BooleanExpressionComplexityCheckTest extends AbstractModuleTestSupp
   }
 
   @Test
-  public void testBooleanExpressionComplexityRecordsAndCompactCtors() throws Exception {
+  void booleanExpressionComplexityRecordsAndCompactCtors() throws Exception {
 
     final int max = 3;
 
@@ -108,7 +108,7 @@ public class BooleanExpressionComplexityCheckTest extends AbstractModuleTestSupp
   }
 
   @Test
-  public void testLeaves() throws Exception {
+  void leaves() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -116,7 +116,7 @@ public class BooleanExpressionComplexityCheckTest extends AbstractModuleTestSupp
   }
 
   @Test
-  public void testRecordLeaves() throws Exception {
+  void recordLeaves() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/metrics/ClassDataAbstractionCouplingCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/metrics/ClassDataAbstractionCouplingCheckTest.java
@@ -31,7 +31,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.antlr.v4.runtime.CommonToken;
 import org.junit.jupiter.api.Test;
 
-public class ClassDataAbstractionCouplingCheckTest extends AbstractModuleTestSupport {
+final class ClassDataAbstractionCouplingCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -39,7 +39,7 @@ public class ClassDataAbstractionCouplingCheckTest extends AbstractModuleTestSup
   }
 
   @Test
-  public void testTokens() {
+  void tokens() {
     final ClassDataAbstractionCouplingCheck check = new ClassDataAbstractionCouplingCheck();
     assertWithMessage("Required tokens should not be null")
         .that(check.getRequiredTokens())
@@ -56,7 +56,7 @@ public class ClassDataAbstractionCouplingCheckTest extends AbstractModuleTestSup
   }
 
   @Test
-  public void test() throws Exception {
+  void test() throws Exception {
 
     final String[] expected = {
       "16:1: " + getCheckMessage(MSG_KEY, 4, 0, "[AnotherInnerClass, HashMap, HashSet, int]"),
@@ -68,7 +68,7 @@ public class ClassDataAbstractionCouplingCheckTest extends AbstractModuleTestSup
   }
 
   @Test
-  public void testExcludedPackageDirectPackages() throws Exception {
+  void excludedPackageDirectPackages() throws Exception {
     final String[] expected = {
       "28:1: " + getCheckMessage(MSG_KEY, 2, 0, "[BasicHttpContext, TlsCiphers]"),
     };
@@ -78,7 +78,7 @@ public class ClassDataAbstractionCouplingCheckTest extends AbstractModuleTestSup
   }
 
   @Test
-  public void testExcludedPackageCommonPackages() throws Exception {
+  void excludedPackageCommonPackages() throws Exception {
     final String[] expected = {
       "28:1: " + getCheckMessage(MSG_KEY, 2, 0, "[BasicHttpContext, TlsCiphers]"),
       "32:5: " + getCheckMessage(MSG_KEY, 2, 0, "[BasicClientTlsStrategy, CommandSupport]"),
@@ -89,7 +89,7 @@ public class ClassDataAbstractionCouplingCheckTest extends AbstractModuleTestSup
   }
 
   @Test
-  public void testExcludedPackageWithEndingDot() throws Exception {
+  void excludedPackageWithEndingDot() throws Exception {
     final DefaultConfiguration checkConfig =
         createModuleConfig(ClassDataAbstractionCouplingCheck.class);
 
@@ -118,20 +118,20 @@ public class ClassDataAbstractionCouplingCheckTest extends AbstractModuleTestSup
   }
 
   @Test
-  public void testExcludedPackageCommonPackagesAllIgnored() throws Exception {
+  void excludedPackageCommonPackagesAllIgnored() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputClassDataAbstractionCouplingExcludedPackagesAllIgnored.java"), expected);
   }
 
   @Test
-  public void testDefaultConfiguration() throws Exception {
+  void defaultConfiguration() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputClassDataAbstractionCoupling2.java"), expected);
   }
 
   @Test
-  public void testWrongToken() {
+  void wrongToken() {
     final ClassDataAbstractionCouplingCheck classDataAbstractionCouplingCheckObj =
         new ClassDataAbstractionCouplingCheck();
     final DetailAstImpl ast = new DetailAstImpl();
@@ -147,7 +147,7 @@ public class ClassDataAbstractionCouplingCheckTest extends AbstractModuleTestSup
   }
 
   @Test
-  public void testRegularExpression() throws Exception {
+  void regularExpression() throws Exception {
 
     final String[] expected = {
       "22:1: " + getCheckMessage(MSG_KEY, 2, 0, "[AnotherInnerClass, int]"),
@@ -158,7 +158,7 @@ public class ClassDataAbstractionCouplingCheckTest extends AbstractModuleTestSup
   }
 
   @Test
-  public void testEmptyRegularExpression() throws Exception {
+  void emptyRegularExpression() throws Exception {
 
     final String[] expected = {
       "22:1: " + getCheckMessage(MSG_KEY, 4, 0, "[AnotherInnerClass, HashMap, HashSet, int]"),
@@ -170,7 +170,7 @@ public class ClassDataAbstractionCouplingCheckTest extends AbstractModuleTestSup
   }
 
   @Test
-  public void testClassDataAbstractionCouplingRecords() throws Exception {
+  void classDataAbstractionCouplingRecords() throws Exception {
 
     final int maxAbstraction = 1;
     final String[] expected = {
@@ -186,7 +186,7 @@ public class ClassDataAbstractionCouplingCheckTest extends AbstractModuleTestSup
   }
 
   @Test
-  public void testNew() throws Exception {
+  void testNew() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/metrics/ClassFanOutComplexityCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/metrics/ClassFanOutComplexityCheckTest.java
@@ -36,7 +36,7 @@ import java.util.Map;
 import java.util.Optional;
 import org.junit.jupiter.api.Test;
 
-public class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
+final class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -44,7 +44,7 @@ public class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test() throws Exception {
+  void test() throws Exception {
 
     final String[] expected = {
       "27:1: " + getCheckMessage(MSG_KEY, 3, 0), "59:1: " + getCheckMessage(MSG_KEY, 1, 0),
@@ -54,7 +54,7 @@ public class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExcludedPackagesDirectPackages() throws Exception {
+  void excludedPackagesDirectPackages() throws Exception {
     final String[] expected = {
       "29:1: " + getCheckMessage(MSG_KEY, 2, 0),
     };
@@ -64,7 +64,7 @@ public class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExcludedPackagesCommonPackages() throws Exception {
+  void excludedPackagesCommonPackages() throws Exception {
     final String[] expected = {
       "28:1: " + getCheckMessage(MSG_KEY, 2, 0),
       "32:5: " + getCheckMessage(MSG_KEY, 2, 0),
@@ -75,7 +75,7 @@ public class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExcludedPackagesCommonPackagesWithEndingDot() throws Exception {
+  void excludedPackagesCommonPackagesWithEndingDot() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(ClassFanOutComplexityCheck.class);
 
     checkConfig.addProperty("max", "0");
@@ -103,14 +103,14 @@ public class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExcludedPackagesAllIgnored() throws Exception {
+  void excludedPackagesAllIgnored() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputClassFanOutComplexityExcludedPackagesAllIgnored.java"), expected);
   }
 
   @Test
-  public void test15() throws Exception {
+  void test15() throws Exception {
 
     final String[] expected = {
       "29:1: " + getCheckMessage(MSG_KEY, 1, 0),
@@ -120,13 +120,13 @@ public class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultConfiguration() throws Exception {
+  void defaultConfiguration() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputClassFanOutComplexity2.java"), expected);
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final ClassFanOutComplexityCheck classFanOutComplexityCheckObj =
         new ClassFanOutComplexityCheck();
     final int[] actual = classFanOutComplexityCheckObj.getAcceptableTokens();
@@ -150,7 +150,7 @@ public class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRegularExpression() throws Exception {
+  void regularExpression() throws Exception {
 
     final String[] expected = {
       "44:1: " + getCheckMessage(MSG_KEY, 2, 0), "76:1: " + getCheckMessage(MSG_KEY, 1, 0),
@@ -160,7 +160,7 @@ public class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyRegularExpression() throws Exception {
+  void emptyRegularExpression() throws Exception {
 
     final String[] expected = {
       "44:1: " + getCheckMessage(MSG_KEY, 3, 0), "76:1: " + getCheckMessage(MSG_KEY, 1, 0),
@@ -170,7 +170,7 @@ public class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithMultiDimensionalArray() throws Exception {
+  void withMultiDimensionalArray() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
@@ -178,14 +178,14 @@ public class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackageName() throws Exception {
+  void packageName() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputClassFanOutComplexityPackageName.java"), expected);
   }
 
   @Test
-  public void testExtends() throws Exception {
+  void testExtends() throws Exception {
     final String[] expected = {
       "23:1: " + getCheckMessage(MSG_KEY, 1, 0),
     };
@@ -193,7 +193,7 @@ public class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testImplements() throws Exception {
+  void testImplements() throws Exception {
     final String[] expected = {
       "23:1: " + getCheckMessage(MSG_KEY, 1, 0),
     };
@@ -201,7 +201,7 @@ public class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotation() throws Exception {
+  void annotation() throws Exception {
     final String[] expected = {
       "29:1: " + getCheckMessage(MSG_KEY, 2, 0),
       "45:5: " + getCheckMessage(MSG_KEY, 2, 0),
@@ -215,7 +215,7 @@ public class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testImplementsAndNestedCount() throws Exception {
+  void implementsAndNestedCount() throws Exception {
     final String[] expected = {
       "26:1: " + getCheckMessage(MSG_KEY, 3, 0),
     };
@@ -224,7 +224,7 @@ public class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClassFanOutComplexityRecords() throws Exception {
+  void classFanOutComplexityRecords() throws Exception {
     final String[] expected = {
       "32:1: " + getCheckMessage(MSG_KEY, 4, 2), "53:1: " + getCheckMessage(MSG_KEY, 4, 2),
     };
@@ -233,27 +233,27 @@ public class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClassFanOutComplexityIgnoreVar() throws Exception {
+  void classFanOutComplexityIgnoreVar() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputClassFanOutComplexityVar.java"), expected);
   }
 
   @Test
-  public void testClassFanOutComplexityRemoveIncorrectAnnotationToken() throws Exception {
+  void classFanOutComplexityRemoveIncorrectAnnotationToken() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputClassFanOutComplexityRemoveIncorrectAnnotationToken.java"), expected);
   }
 
   @Test
-  public void testClassFanOutComplexityRemoveIncorrectTypeParameter() throws Exception {
+  void classFanOutComplexityRemoveIncorrectTypeParameter() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputClassFanOutComplexityRemoveIncorrectTypeParameter.java"), expected);
   }
 
   @Test
-  public void testClassFanOutComplexityMultiCatchBitwiseOr() throws Exception {
+  void classFanOutComplexityMultiCatchBitwiseOr() throws Exception {
     final String[] expected = {
       "27:1: " + getCheckMessage(MSG_KEY, 5, 4),
     };
@@ -263,7 +263,7 @@ public class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testThrows() throws Exception {
+  void testThrows() throws Exception {
     final String[] expected = {
       "25:1: " + getCheckMessage(MSG_KEY, 2, 0),
     };
@@ -277,9 +277,9 @@ public class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
    *
    * @throws Exception when code tested throws exception
    */
-  @Test
   @SuppressWarnings("unchecked")
-  public void testClearStateImportedClassPackages() throws Exception {
+  @Test
+  void clearStateImportedClassPackages() throws Exception {
     final ClassFanOutComplexityCheck check = new ClassFanOutComplexityCheck();
     final DetailAST root =
         JavaParser.parseFile(
@@ -293,7 +293,7 @@ public class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
         .that(
             TestUtil.isStatefulFieldClearedDuringBeginTree(
                 check,
-                importAst.get(),
+                importAst.orElseThrow(),
                 "importedClassPackages",
                 importedClssPackage -> ((Map<String, String>) importedClssPackage).isEmpty()))
         .isTrue();
@@ -306,7 +306,7 @@ public class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
    * @throws Exception when code tested throws exception
    */
   @Test
-  public void testClearStateClassContexts() throws Exception {
+  void clearStateClassContexts() throws Exception {
     final ClassFanOutComplexityCheck check = new ClassFanOutComplexityCheck();
     final DetailAST root =
         JavaParser.parseFile(
@@ -320,7 +320,7 @@ public class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
         .that(
             TestUtil.isStatefulFieldClearedDuringBeginTree(
                 check,
-                classDef.get(),
+                classDef.orElseThrow(),
                 "classesContexts",
                 classContexts -> ((Collection<?>) classContexts).size() == 1))
         .isTrue();
@@ -333,7 +333,7 @@ public class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
    * @throws Exception when code tested throws exception
    */
   @Test
-  public void testClearStatePackageName() throws Exception {
+  void clearStatePackageName() throws Exception {
     final ClassFanOutComplexityCheck check = new ClassFanOutComplexityCheck();
     final DetailAST root =
         JavaParser.parseFile(
@@ -347,7 +347,7 @@ public class ClassFanOutComplexityCheckTest extends AbstractModuleTestSupport {
         .that(
             TestUtil.isStatefulFieldClearedDuringBeginTree(
                 check,
-                packageDef.get(),
+                packageDef.orElseThrow(),
                 "packageName",
                 packageName -> ((String) packageName).isEmpty()))
         .isTrue();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/metrics/CyclomaticComplexityCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/metrics/CyclomaticComplexityCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class CyclomaticComplexityCheckTest extends AbstractModuleTestSupport {
+final class CyclomaticComplexityCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class CyclomaticComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSwitchBlockAsSingleDecisionPointSetToTrue() throws Exception {
+  void switchBlockAsSingleDecisionPointSetToTrue() throws Exception {
 
     final String[] expected = {
       "14:5: " + getCheckMessage(MSG_KEY, 2, 0),
@@ -45,7 +45,7 @@ public class CyclomaticComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSwitchBlockAsSingleDecisionPointSetToFalse() throws Exception {
+  void switchBlockAsSingleDecisionPointSetToFalse() throws Exception {
 
     final String[] expected = {
       "14:5: " + getCheckMessage(MSG_KEY, 5, 0),
@@ -55,7 +55,7 @@ public class CyclomaticComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEqualsMaxComplexity() throws Exception {
+  void equalsMaxComplexity() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -63,7 +63,7 @@ public class CyclomaticComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test() throws Exception {
+  void test() throws Exception {
 
     final String[] expected = {
       "15:5: " + getCheckMessage(MSG_KEY, 2, 0),
@@ -82,7 +82,7 @@ public class CyclomaticComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCyclomaticComplexityRecords() throws Exception {
+  void cyclomaticComplexityRecords() throws Exception {
 
     final int max = 0;
 
@@ -99,7 +99,7 @@ public class CyclomaticComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final CyclomaticComplexityCheck cyclomaticComplexityCheckObj = new CyclomaticComplexityCheck();
     final int[] actual = cyclomaticComplexityCheckObj.getAcceptableTokens();
     final int[] expected = {
@@ -123,7 +123,7 @@ public class CyclomaticComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final CyclomaticComplexityCheck cyclomaticComplexityCheckObj = new CyclomaticComplexityCheck();
     final int[] actual = cyclomaticComplexityCheckObj.getRequiredTokens();
     final int[] expected = {
@@ -137,14 +137,14 @@ public class CyclomaticComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHighMax() throws Exception {
+  void highMax() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputCyclomaticComplexitySwitchBlocks4.java"), expected);
   }
 
   @Test
-  public void testDefaultMax() throws Exception {
+  void defaultMax() throws Exception {
     final String[] expected = {
       "14:5: " + getCheckMessage(MSG_KEY, 12, 10),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/metrics/JavaNCSSCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/metrics/JavaNCSSCheckTest.java
@@ -32,7 +32,7 @@ import org.junit.jupiter.api.Test;
 
 /** Test case for the JavaNCSS-Check. */
 // -@cs[AbbreviationAsWordInName] Test should be named as its main class.
-public class JavaNCSSCheckTest extends AbstractModuleTestSupport {
+final class JavaNCSSCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -40,7 +40,7 @@ public class JavaNCSSCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test() throws Exception {
+  void test() throws Exception {
 
     final String[] expected = {
       "12:1: " + getCheckMessage(MSG_FILE, 39, 2),
@@ -62,7 +62,7 @@ public class JavaNCSSCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEqualToMax() throws Exception {
+  void equalToMax() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -70,13 +70,13 @@ public class JavaNCSSCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultConfiguration() throws Exception {
+  void defaultConfiguration() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJavaNCSS3.java"), expected);
   }
 
   @Test
-  public void testRecordsAndCompactCtors() throws Exception {
+  void recordsAndCompactCtors() throws Exception {
 
     final String[] expected = {
       "12:1: " + getCheckMessage(MSG_FILE, 89, 2),
@@ -99,7 +99,7 @@ public class JavaNCSSCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testForMutation() throws Exception {
+  void forMutation() throws Exception {
     final String[] expected = {
       "13:1: " + getCheckMessage(MSG_CLASS, 84, 80), "16:5: " + getCheckMessage(MSG_CLASS, 83, 80),
     };
@@ -107,7 +107,7 @@ public class JavaNCSSCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRecordMax() throws Exception {
+  void recordMax() throws Exception {
     final String[] expected = {
       "14:1: " + getCheckMessage(MSG_CLASS, 152, 80),
       "15:5: " + getCheckMessage(MSG_RECORD, 151, 150),
@@ -117,7 +117,7 @@ public class JavaNCSSCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final JavaNCSSCheck javaNcssCheckObj = new JavaNCSSCheck();
     final int[] actual = javaNcssCheckObj.getAcceptableTokens();
     final int[] expected = {
@@ -157,7 +157,7 @@ public class JavaNCSSCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final JavaNCSSCheck javaNcssCheckObj = new JavaNCSSCheck();
     final int[] actual = javaNcssCheckObj.getRequiredTokens();
     final int[] expected = {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/metrics/NPathComplexityCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/metrics/NPathComplexityCheckTest.java
@@ -40,7 +40,7 @@ import org.antlr.v4.runtime.CommonToken;
 import org.junit.jupiter.api.Test;
 
 // -@cs[AbbreviationAsWordInName] Can't change check name
-public class NPathComplexityCheckTest extends AbstractModuleTestSupport {
+final class NPathComplexityCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -48,7 +48,7 @@ public class NPathComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCalculation() throws Exception {
+  void calculation() throws Exception {
     final String[] expected = {
       "12:5: " + getCheckMessage(MSG_KEY, 2, 0),
       "17:17: " + getCheckMessage(MSG_KEY, 2, 0),
@@ -70,7 +70,7 @@ public class NPathComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCalculation2() throws Exception {
+  void calculation2() throws Exception {
     final String[] expected = {
       "12:5: " + getCheckMessage(MSG_KEY, 5, 0),
       "18:5: " + getCheckMessage(MSG_KEY, 5, 0),
@@ -92,7 +92,7 @@ public class NPathComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCalculation3() throws Exception {
+  void calculation3() throws Exception {
     final String[] expected = {
       "11:5: " + getCheckMessage(MSG_KEY, 64, 0),
     };
@@ -102,7 +102,7 @@ public class NPathComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIntegerOverflow() throws Exception {
+  void integerOverflow() throws Exception {
 
     final long largerThanMaxInt = 3_486_784_401L;
 
@@ -113,9 +113,9 @@ public class NPathComplexityCheckTest extends AbstractModuleTestSupport {
     verifyWithInlineConfigParser(getPath("InputNPathComplexityOverflow.java"), expected);
   }
 
-  @Test
   @SuppressWarnings("unchecked")
-  public void testStatefulFieldsClearedOnBeginTree1() {
+  @Test
+  void statefulFieldsClearedOnBeginTree1() {
     final DetailAstImpl ast = new DetailAstImpl();
     ast.setType(TokenTypes.LITERAL_ELSE);
 
@@ -151,9 +151,9 @@ public class NPathComplexityCheckTest extends AbstractModuleTestSupport {
         .isTrue();
   }
 
-  @Test
   @SuppressWarnings("unchecked")
-  public void testStatefulFieldsClearedOnBeginTree2() {
+  @Test
+  void statefulFieldsClearedOnBeginTree2() {
     final DetailAstImpl ast = new DetailAstImpl();
     ast.setType(TokenTypes.LITERAL_RETURN);
     ast.setLineNo(5);
@@ -173,7 +173,7 @@ public class NPathComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStatefulFieldsClearedOnBeginTree3() throws Exception {
+  void statefulFieldsClearedOnBeginTree3() throws Exception {
     final NPathComplexityCheck check = new NPathComplexityCheck();
     final Optional<DetailAST> question =
         TestUtil.findTokenInAstByPredicate(
@@ -188,7 +188,7 @@ public class NPathComplexityCheckTest extends AbstractModuleTestSupport {
         .that(
             TestUtil.isStatefulFieldClearedDuringBeginTree(
                 check,
-                question.get(),
+                question.orElseThrow(),
                 "processingTokenEnd",
                 processingTokenEnd -> {
                   return TestUtil.<Integer>getInternalState(processingTokenEnd, "endLineNo") == 0
@@ -198,13 +198,13 @@ public class NPathComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultConfiguration() throws Exception {
+  void defaultConfiguration() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputNPathComplexityDefault2.java"), expected);
   }
 
   @Test
-  public void testNpathComplexityRecords() throws Exception {
+  void npathComplexityRecords() throws Exception {
     final int max = 1;
 
     final String[] expected = {
@@ -219,7 +219,7 @@ public class NPathComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNpathComplexitySwitchExpression() throws Exception {
+  void npathComplexitySwitchExpression() throws Exception {
 
     final int max = 1;
 
@@ -235,7 +235,7 @@ public class NPathComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBranchVisited() throws Exception {
+  void branchVisited() throws Exception {
 
     final String[] expected = {
       "13:3: " + getCheckMessage(MSG_KEY, 37, 20),
@@ -245,7 +245,7 @@ public class NPathComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCount() throws Exception {
+  void count() throws Exception {
 
     final String[] expected = {
       "11:5: " + getCheckMessage(MSG_KEY, 30, 20),
@@ -257,7 +257,7 @@ public class NPathComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final NPathComplexityCheck npathComplexityCheckObj = new NPathComplexityCheck();
     final int[] actual = npathComplexityCheckObj.getAcceptableTokens();
     final int[] expected = {
@@ -285,7 +285,7 @@ public class NPathComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final NPathComplexityCheck npathComplexityCheckObj = new NPathComplexityCheck();
     final int[] actual = npathComplexityCheckObj.getRequiredTokens();
     final int[] expected = {
@@ -313,7 +313,7 @@ public class NPathComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultHooks() {
+  void defaultHooks() {
     final NPathComplexityCheck npathComplexityCheckObj = new NPathComplexityCheck();
     final DetailAstImpl ast = new DetailAstImpl();
     ast.initialize(new CommonToken(TokenTypes.INTERFACE_DEF, "interface"));
@@ -341,7 +341,7 @@ public class NPathComplexityCheckTest extends AbstractModuleTestSupport {
    * @throws Exception if there is an error.
    */
   @Test
-  public void testTokenEndIsAfterSameLineColumn() throws Exception {
+  void tokenEndIsAfterSameLineColumn() throws Exception {
     final NPathComplexityCheck check = new NPathComplexityCheck();
     final Object tokenEnd = TestUtil.getInternalState(check, "processingTokenEnd");
     final DetailAstImpl token = new DetailAstImpl();
@@ -354,7 +354,7 @@ public class NPathComplexityCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testVisitTokenBeforeExpressionRange() {
+  void visitTokenBeforeExpressionRange() {
     // Create first ast
     final DetailAstImpl astIf = mockAST(TokenTypes.LITERAL_IF, "if", 2, 2);
     final DetailAstImpl astIfLeftParen = mockAST(TokenTypes.LPAREN, "(", 3, 3);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/modifier/ClassMemberImpliedModifierCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/modifier/ClassMemberImpliedModifierCheckTest.java
@@ -28,7 +28,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class ClassMemberImpliedModifierCheckTest extends AbstractModuleTestSupport {
+final class ClassMemberImpliedModifierCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -36,7 +36,7 @@ public class ClassMemberImpliedModifierCheckTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testMethodsOnClass() throws Exception {
+  void methodsOnClass() throws Exception {
     final String[] expected = {
       "51:9: " + getCheckMessage(MSG_KEY, "static"),
       "58:9: " + getCheckMessage(MSG_KEY, "static"),
@@ -49,7 +49,7 @@ public class ClassMemberImpliedModifierCheckTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final ClassMemberImpliedModifierCheck check = new ClassMemberImpliedModifierCheck();
     final int[] actual = check.getRequiredTokens();
     final int[] expected = {
@@ -59,7 +59,7 @@ public class ClassMemberImpliedModifierCheckTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testMethodsOnClassNoImpliedStaticEnum() throws Exception {
+  void methodsOnClassNoImpliedStaticEnum() throws Exception {
     final String[] expected = {
       "59:9: " + getCheckMessage(MSG_KEY, "static"),
       "77:9: " + getCheckMessage(MSG_KEY, "static"),
@@ -70,7 +70,7 @@ public class ClassMemberImpliedModifierCheckTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testMethodsOnClassNoImpliedStaticInterface() throws Exception {
+  void methodsOnClassNoImpliedStaticInterface() throws Exception {
     final String[] expected = {
       "52:9: " + getCheckMessage(MSG_KEY, "static"),
       "63:5: " + getCheckMessage(MSG_KEY, "static"),
@@ -81,14 +81,14 @@ public class ClassMemberImpliedModifierCheckTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testMethodsOnClassNoViolationsChecked() throws Exception {
+  void methodsOnClassNoViolationsChecked() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputClassMemberImpliedModifierOnClassNoViolations.java"), expected);
   }
 
   @Test
-  public void testMethodsOnInterface() throws Exception {
+  void methodsOnInterface() throws Exception {
     final String[] expected = {
       "60:13: " + getCheckMessage(MSG_KEY, "static"),
       "67:13: " + getCheckMessage(MSG_KEY, "static"),
@@ -102,7 +102,7 @@ public class ClassMemberImpliedModifierCheckTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testClassMemberImpliedModifierRecords() throws Exception {
+  void classMemberImpliedModifierRecords() throws Exception {
     final String[] expected = {
       "16:5: " + getCheckMessage(MSG_KEY, "static"),
       "20:5: " + getCheckMessage(MSG_KEY, "static"),
@@ -117,7 +117,7 @@ public class ClassMemberImpliedModifierCheckTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testClassMemberImpliedModifierNoViolationRecords() throws Exception {
+  void classMemberImpliedModifierNoViolationRecords() throws Exception {
     final String[] expected = {
       "16:5: " + getCheckMessage(MSG_KEY, "static"),
       "20:5: " + getCheckMessage(MSG_KEY, "static"),
@@ -129,7 +129,7 @@ public class ClassMemberImpliedModifierCheckTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testIllegalState() {
+  void illegalState() {
     final DetailAstImpl init = new DetailAstImpl();
     init.setType(TokenTypes.STATIC_INIT);
     final DetailAstImpl objBlock = new DetailAstImpl();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/modifier/InterfaceMemberImpliedModifierCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/modifier/InterfaceMemberImpliedModifierCheckTest.java
@@ -28,7 +28,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class InterfaceMemberImpliedModifierCheckTest extends AbstractModuleTestSupport {
+final class InterfaceMemberImpliedModifierCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -36,7 +36,7 @@ public class InterfaceMemberImpliedModifierCheckTest extends AbstractModuleTestS
   }
 
   @Test
-  public void testMethodsOnInterfaceNoImpliedPublicAbstract() throws Exception {
+  void methodsOnInterfaceNoImpliedPublicAbstract() throws Exception {
     final String[] expected = {
       "21:5: " + getCheckMessage(MSG_KEY, "public"),
       "27:5: " + getCheckMessage(MSG_KEY, "public"),
@@ -50,7 +50,7 @@ public class InterfaceMemberImpliedModifierCheckTest extends AbstractModuleTestS
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final InterfaceMemberImpliedModifierCheck check = new InterfaceMemberImpliedModifierCheck();
     final int[] actual = check.getRequiredTokens();
     final int[] expected = {
@@ -64,7 +64,7 @@ public class InterfaceMemberImpliedModifierCheckTest extends AbstractModuleTestS
   }
 
   @Test
-  public void testMethodsOnInterfaceNoImpliedAbstractAllowImpliedPublic() throws Exception {
+  void methodsOnInterfaceNoImpliedAbstractAllowImpliedPublic() throws Exception {
     final String[] expected = {
       "36:5: " + getCheckMessage(MSG_KEY, "abstract"),
       "38:5: " + getCheckMessage(MSG_KEY, "abstract"),
@@ -74,7 +74,7 @@ public class InterfaceMemberImpliedModifierCheckTest extends AbstractModuleTestS
   }
 
   @Test
-  public void testMethodsOnInterfaceNoImpliedPublicAllowImpliedAbstract() throws Exception {
+  void methodsOnInterfaceNoImpliedPublicAllowImpliedAbstract() throws Exception {
     final String[] expected = {
       "21:5: " + getCheckMessage(MSG_KEY, "public"),
       "27:5: " + getCheckMessage(MSG_KEY, "public"),
@@ -86,21 +86,21 @@ public class InterfaceMemberImpliedModifierCheckTest extends AbstractModuleTestS
   }
 
   @Test
-  public void testMethodsOnInterfaceAllowImpliedPublicAbstract() throws Exception {
+  void methodsOnInterfaceAllowImpliedPublicAbstract() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputInterfaceMemberImpliedModifierMethodsOnInterface4.java"), expected);
   }
 
   @Test
-  public void testMethodsOnClassIgnored() throws Exception {
+  void methodsOnClassIgnored() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputInterfaceMemberImpliedModifierMethodsOnClass.java"), expected);
   }
 
   @Test
-  public void testMethodsOnInterfaceNestedNoImpliedPublicAbstract() throws Exception {
+  void methodsOnInterfaceNestedNoImpliedPublicAbstract() throws Exception {
     final String[] expected = {
       "23:9: " + getCheckMessage(MSG_KEY, "public"),
       "29:9: " + getCheckMessage(MSG_KEY, "public"),
@@ -114,7 +114,7 @@ public class InterfaceMemberImpliedModifierCheckTest extends AbstractModuleTestS
   }
 
   @Test
-  public void testMethodsOnClassNestedNoImpliedPublicAbstract() throws Exception {
+  void methodsOnClassNestedNoImpliedPublicAbstract() throws Exception {
     final String[] expected = {
       "23:9: " + getCheckMessage(MSG_KEY, "public"),
       "29:9: " + getCheckMessage(MSG_KEY, "public"),
@@ -128,7 +128,7 @@ public class InterfaceMemberImpliedModifierCheckTest extends AbstractModuleTestS
   }
 
   @Test
-  public void testFieldsOnInterfaceNoImpliedPublicStaticFinal() throws Exception {
+  void fieldsOnInterfaceNoImpliedPublicStaticFinal() throws Exception {
     final String[] expected = {
       "20:5: " + getCheckMessage(MSG_KEY, "final"),
       "22:5: " + getCheckMessage(MSG_KEY, "static"),
@@ -148,7 +148,7 @@ public class InterfaceMemberImpliedModifierCheckTest extends AbstractModuleTestS
   }
 
   @Test
-  public void testFieldsOnInterfaceNoImpliedPublicStaticAllowImpliedFinal() throws Exception {
+  void fieldsOnInterfaceNoImpliedPublicStaticAllowImpliedFinal() throws Exception {
     final String[] expected = {
       "22:5: " + getCheckMessage(MSG_KEY, "static"),
       "24:5: " + getCheckMessage(MSG_KEY, "static"),
@@ -164,7 +164,7 @@ public class InterfaceMemberImpliedModifierCheckTest extends AbstractModuleTestS
   }
 
   @Test
-  public void testFieldsOnInterfaceNoImpliedPublicFinalAllowImpliedStatic() throws Exception {
+  void fieldsOnInterfaceNoImpliedPublicFinalAllowImpliedStatic() throws Exception {
     final String[] expected = {
       "20:5: " + getCheckMessage(MSG_KEY, "final"),
       "24:5: " + getCheckMessage(MSG_KEY, "final"),
@@ -180,7 +180,7 @@ public class InterfaceMemberImpliedModifierCheckTest extends AbstractModuleTestS
   }
 
   @Test
-  public void testFieldsOnInterfaceNoImpliedStaticFinalAllowImpliedPublic() throws Exception {
+  void fieldsOnInterfaceNoImpliedStaticFinalAllowImpliedPublic() throws Exception {
     final String[] expected = {
       "20:5: " + getCheckMessage(MSG_KEY, "final"),
       "22:5: " + getCheckMessage(MSG_KEY, "static"),
@@ -196,21 +196,21 @@ public class InterfaceMemberImpliedModifierCheckTest extends AbstractModuleTestS
   }
 
   @Test
-  public void testFieldsOnInterfaceAllowImpliedPublicStaticFinal() throws Exception {
+  void fieldsOnInterfaceAllowImpliedPublicStaticFinal() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputInterfaceMemberImpliedModifierFieldsOnInterface5.java"), expected);
   }
 
   @Test
-  public void testFieldsOnClassIgnored() throws Exception {
+  void fieldsOnClassIgnored() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputInterfaceMemberImpliedModifierFieldsOnClass.java"), expected);
   }
 
   @Test
-  public void testNestedOnInterfaceNoImpliedPublicStatic() throws Exception {
+  void nestedOnInterfaceNoImpliedPublicStatic() throws Exception {
     final String[] expected = {
       "21:5: " + getCheckMessage(MSG_KEY, "static"),
       "24:5: " + getCheckMessage(MSG_KEY, "public"),
@@ -230,7 +230,7 @@ public class InterfaceMemberImpliedModifierCheckTest extends AbstractModuleTestS
   }
 
   @Test
-  public void testNestedOnInterfaceNoImpliedStaticAllowImpliedPublic() throws Exception {
+  void nestedOnInterfaceNoImpliedStaticAllowImpliedPublic() throws Exception {
     final String[] expected = {
       "21:5: " + getCheckMessage(MSG_KEY, "static"),
       "27:5: " + getCheckMessage(MSG_KEY, "static"),
@@ -244,7 +244,7 @@ public class InterfaceMemberImpliedModifierCheckTest extends AbstractModuleTestS
   }
 
   @Test
-  public void testNestedOnInterfaceNoImpliedPublicAllowImpliedStatic() throws Exception {
+  void nestedOnInterfaceNoImpliedPublicAllowImpliedStatic() throws Exception {
     final String[] expected = {
       "24:5: " + getCheckMessage(MSG_KEY, "public"),
       "27:5: " + getCheckMessage(MSG_KEY, "public"),
@@ -258,21 +258,21 @@ public class InterfaceMemberImpliedModifierCheckTest extends AbstractModuleTestS
   }
 
   @Test
-  public void testNestedOnInterfaceAllowImpliedPublicStatic() throws Exception {
+  void nestedOnInterfaceAllowImpliedPublicStatic() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputInterfaceMemberImpliedModifierNestedOnInterface4.java"), expected);
   }
 
   @Test
-  public void testNestedOnClassIgnored() throws Exception {
+  void nestedOnClassIgnored() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputInterfaceMemberImpliedModifierNestedOnClass.java"), expected);
   }
 
   @Test
-  public void testNestedOnInterfaceNestedNoImpliedPublicStatic() throws Exception {
+  void nestedOnInterfaceNestedNoImpliedPublicStatic() throws Exception {
     final String[] expected = {
       "20:9: " + getCheckMessage(MSG_KEY, "public"),
       "20:9: " + getCheckMessage(MSG_KEY, "static"),
@@ -286,7 +286,7 @@ public class InterfaceMemberImpliedModifierCheckTest extends AbstractModuleTestS
   }
 
   @Test
-  public void testNestedOnClassNestedNoImpliedPublicStatic() throws Exception {
+  void nestedOnClassNestedNoImpliedPublicStatic() throws Exception {
     final String[] expected = {
       "20:9: " + getCheckMessage(MSG_KEY, "public"),
       "20:9: " + getCheckMessage(MSG_KEY, "static"),
@@ -300,7 +300,7 @@ public class InterfaceMemberImpliedModifierCheckTest extends AbstractModuleTestS
   }
 
   @Test
-  public void testPackageScopeInterface() throws Exception {
+  void packageScopeInterface() throws Exception {
     final String[] expected = {
       "20:5: " + getCheckMessage(MSG_KEY, "final"),
       "22:5: " + getCheckMessage(MSG_KEY, "static"),
@@ -330,14 +330,14 @@ public class InterfaceMemberImpliedModifierCheckTest extends AbstractModuleTestS
   }
 
   @Test
-  public void testPrivateMethodsOnInterface() throws Exception {
+  void privateMethodsOnInterface() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputInterfaceMemberImpliedModifierPrivateMethods.java"), expected);
   }
 
   @Test
-  public void testIllegalState() {
+  void illegalState() {
     final DetailAstImpl init = new DetailAstImpl();
     init.setType(TokenTypes.STATIC_INIT);
     final DetailAstImpl objBlock = new DetailAstImpl();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/modifier/ModifierOrderCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/modifier/ModifierOrderCheckTest.java
@@ -28,7 +28,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class ModifierOrderCheckTest extends AbstractModuleTestSupport {
+final class ModifierOrderCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -36,7 +36,7 @@ public class ModifierOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final ModifierOrderCheck checkObj = new ModifierOrderCheck();
     final int[] expected = {TokenTypes.MODIFIERS};
     assertWithMessage("Default required tokens are invalid")
@@ -45,7 +45,7 @@ public class ModifierOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIt() throws Exception {
+  void it() throws Exception {
     final String[] expected = {
       "15:10: " + getCheckMessage(MSG_MODIFIER_ORDER, "final"),
       "19:12: " + getCheckMessage(MSG_MODIFIER_ORDER, "private"),
@@ -59,13 +59,13 @@ public class ModifierOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultMethods() throws Exception {
+  void defaultMethods() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputModifierOrderDefaultMethods.java"), expected);
   }
 
   @Test
-  public void testGetDefaultTokens() {
+  void getDefaultTokens() {
     final ModifierOrderCheck modifierOrderCheckObj = new ModifierOrderCheck();
     final int[] actual = modifierOrderCheckObj.getDefaultTokens();
     final int[] expected = {TokenTypes.MODIFIERS};
@@ -82,7 +82,7 @@ public class ModifierOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final ModifierOrderCheck modifierOrderCheckObj = new ModifierOrderCheck();
     final int[] actual = modifierOrderCheckObj.getAcceptableTokens();
     final int[] expected = {TokenTypes.MODIFIERS};
@@ -99,7 +99,7 @@ public class ModifierOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSkipTypeAnnotations() throws Exception {
+  void skipTypeAnnotations() throws Exception {
     final String[] expected = {
       "110:13: " + getCheckMessage(MSG_ANNOTATION_ORDER, "@MethodAnnotation"),
     };
@@ -107,7 +107,7 @@ public class ModifierOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationOnAnnotationDeclaration() throws Exception {
+  void annotationOnAnnotationDeclaration() throws Exception {
     final String[] expected = {
       "9:8: " + getCheckMessage(MSG_ANNOTATION_ORDER, "@InterfaceAnnotation"),
     };
@@ -115,7 +115,7 @@ public class ModifierOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testModifierOrderSealedAndNonSealed() throws Exception {
+  void modifierOrderSealedAndNonSealed() throws Exception {
     final String[] expected = {
       "10:8: " + getCheckMessage(MSG_MODIFIER_ORDER, "public"),
       "26:12: " + getCheckMessage(MSG_MODIFIER_ORDER, "private"),
@@ -129,7 +129,7 @@ public class ModifierOrderCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testModifierOrderSealedAndNonSealedNoViolation() throws Exception {
+  void modifierOrderSealedAndNonSealedNoViolation() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getNonCompilablePath("InputModifierOrderSealedAndNonSealedNoViolation.java"), expected);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/modifier/RedundantModifierCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/modifier/RedundantModifierCheckTest.java
@@ -29,7 +29,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class RedundantModifierCheckTest extends AbstractModuleTestSupport {
+final class RedundantModifierCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -37,7 +37,7 @@ public class RedundantModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClassesInsideOfInterfaces() throws Exception {
+  void classesInsideOfInterfaces() throws Exception {
     final String[] expected = {
       "19:5: " + getCheckMessage(MSG_KEY, "static"),
       "25:5: " + getCheckMessage(MSG_KEY, "public"),
@@ -49,7 +49,7 @@ public class RedundantModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIt() throws Exception {
+  void it() throws Exception {
     final String[] expected = {
       "57:12: " + getCheckMessage(MSG_KEY, "static"),
       "60:9: " + getCheckMessage(MSG_KEY, "public"),
@@ -70,14 +70,14 @@ public class RedundantModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStaticMethodInInterface() throws Exception {
+  void staticMethodInInterface() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputRedundantModifierStaticMethodInInterface.java"), expected);
   }
 
   @Test
-  public void testFinalInInterface() throws Exception {
+  void finalInInterface() throws Exception {
     final String[] expected = {
       "13:9: " + getCheckMessage(MSG_KEY, "final"),
     };
@@ -85,7 +85,7 @@ public class RedundantModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEnumConstructorIsImplicitlyPrivate() throws Exception {
+  void enumConstructorIsImplicitlyPrivate() throws Exception {
     final String[] expected = {
       "14:5: " + getCheckMessage(MSG_KEY, "private"),
     };
@@ -94,7 +94,7 @@ public class RedundantModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInnerTypeInInterfaceIsImplicitlyStatic() throws Exception {
+  void innerTypeInInterfaceIsImplicitlyStatic() throws Exception {
     final String[] expected = {
       "12:5: " + getCheckMessage(MSG_KEY, "static"), "16:5: " + getCheckMessage(MSG_KEY, "static"),
     };
@@ -103,7 +103,7 @@ public class RedundantModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNotPublicClassConstructorHasNotPublicModifier() throws Exception {
+  void notPublicClassConstructorHasNotPublicModifier() throws Exception {
 
     final String[] expected = {
       "22:5: " + getCheckMessage(MSG_KEY, "public"),
@@ -113,7 +113,7 @@ public class RedundantModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNestedClassConsInPublicInterfaceHasValidPublicModifier() throws Exception {
+  void nestedClassConsInPublicInterfaceHasValidPublicModifier() throws Exception {
 
     final String[] expected = {
       "22:17: " + getCheckMessage(MSG_KEY, "public"),
@@ -127,7 +127,7 @@ public class RedundantModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final RedundantModifierCheck redundantModifierCheckObj = new RedundantModifierCheck();
     final int[] actual = redundantModifierCheckObj.getAcceptableTokens();
     final int[] expected = {
@@ -146,7 +146,7 @@ public class RedundantModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWrongTokenType() {
+  void wrongTokenType() {
     final RedundantModifierCheck obj = new RedundantModifierCheck();
     final DetailAstImpl ast = new DetailAstImpl();
     ast.initialize(TokenTypes.LITERAL_NULL, "null");
@@ -165,7 +165,7 @@ public class RedundantModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final RedundantModifierCheck redundantModifierCheckObj = new RedundantModifierCheck();
     final int[] actual = redundantModifierCheckObj.getRequiredTokens();
     final int[] expected = CommonUtil.EMPTY_INT_ARRAY;
@@ -173,7 +173,7 @@ public class RedundantModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNestedStaticEnum() throws Exception {
+  void nestedStaticEnum() throws Exception {
     final String[] expected = {
       "12:5: " + getCheckMessage(MSG_KEY, "static"),
       "16:9: " + getCheckMessage(MSG_KEY, "static"),
@@ -184,7 +184,7 @@ public class RedundantModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFinalInAnonymousClass() throws Exception {
+  void finalInAnonymousClass() throws Exception {
     final String[] expected = {
       "22:20: " + getCheckMessage(MSG_KEY, "final"),
     };
@@ -193,7 +193,7 @@ public class RedundantModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFinalInTryWithResource() throws Exception {
+  void finalInTryWithResource() throws Exception {
     final String[] expected = {
       "38:14: " + getCheckMessage(MSG_KEY, "final"),
       "43:14: " + getCheckMessage(MSG_KEY, "final"),
@@ -204,7 +204,7 @@ public class RedundantModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFinalInAbstractMethods() throws Exception {
+  void finalInAbstractMethods() throws Exception {
     final String[] expected = {
       "12:33: " + getCheckMessage(MSG_KEY, "final"),
       "16:49: " + getCheckMessage(MSG_KEY, "final"),
@@ -217,7 +217,7 @@ public class RedundantModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEnumMethods() throws Exception {
+  void enumMethods() throws Exception {
     final String[] expected = {
       "15:16: " + getCheckMessage(MSG_KEY, "final"), "30:16: " + getCheckMessage(MSG_KEY, "final"),
     };
@@ -226,7 +226,7 @@ public class RedundantModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEnumStaticMethodsInPublicClass() throws Exception {
+  void enumStaticMethodsInPublicClass() throws Exception {
     final String[] expected = {
       "20:23: " + getCheckMessage(MSG_KEY, "final"),
     };
@@ -235,7 +235,7 @@ public class RedundantModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationOnEnumConstructor() throws Exception {
+  void annotationOnEnumConstructor() throws Exception {
     final String[] expected = {
       "22:5: " + getCheckMessage(MSG_KEY, "private"),
     };
@@ -244,7 +244,7 @@ public class RedundantModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPrivateMethodInPrivateClass() throws Exception {
+  void privateMethodInPrivateClass() throws Exception {
     final String[] expected = {
       "13:17: " + getCheckMessage(MSG_KEY, "final"),
     };
@@ -253,7 +253,7 @@ public class RedundantModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTryWithResourcesBlock() throws Exception {
+  void tryWithResourcesBlock() throws Exception {
     final String[] expected = {
       "18:19: " + getCheckMessage(MSG_KEY, "final"),
     };
@@ -261,7 +261,7 @@ public class RedundantModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNestedDef() throws Exception {
+  void nestedDef() throws Exception {
     final String[] expected = {
       "10:5: " + getCheckMessage(MSG_KEY, "public"),
       "11:5: " + getCheckMessage(MSG_KEY, "static"),
@@ -291,7 +291,7 @@ public class RedundantModifierCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRecords() throws Exception {
+  void records() throws Exception {
     final String[] expected = {
       "12:5: " + getCheckMessage(MSG_KEY, "static"),
       "16:9: " + getCheckMessage(MSG_KEY, "final"),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/AbbreviationAsWordInNameCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/AbbreviationAsWordInNameCheckTest.java
@@ -25,7 +25,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport {
+final class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final int expectedCapitalCount = 4;
 
     final String[] expected = {
@@ -51,7 +51,7 @@ public class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testTypeNamesForThreePermittedCapitalLetters() throws Exception {
+  void typeNamesForThreePermittedCapitalLetters() throws Exception {
     final int expectedCapitalCount = 4;
 
     final String[] expected = {
@@ -65,7 +65,7 @@ public class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testTypeNamesForFourPermittedCapitalLetters() throws Exception {
+  void typeNamesForFourPermittedCapitalLetters() throws Exception {
     final int expectedCapitalCount = 5;
 
     final String[] expected = {
@@ -76,7 +76,7 @@ public class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testTypeNamesForFivePermittedCapitalLetters() throws Exception {
+  void typeNamesForFivePermittedCapitalLetters() throws Exception {
     final int expectedCapitalCount = 6;
     final String[] expected = {
       "45:11: " + getWarningMessage("AbstractINNERRClass", expectedCapitalCount),
@@ -87,7 +87,7 @@ public class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testTypeAndVariablesAndMethodNames() throws Exception {
+  void typeAndVariablesAndMethodNames() throws Exception {
     final int expectedCapitalCount = 6;
 
     final String[] expected = {
@@ -102,7 +102,7 @@ public class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testTypeAndVariablesAndMethodNamesWithNoIgnores() throws Exception {
+  void typeAndVariablesAndMethodNamesWithNoIgnores() throws Exception {
     final int expectedCapitalCount = 6;
 
     final String[] expected = {
@@ -122,7 +122,7 @@ public class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testTypeAndVariablesAndMethodNamesWithIgnores() throws Exception {
+  void typeAndVariablesAndMethodNamesWithIgnores() throws Exception {
     final int expectedCapitalCount = 6;
 
     final String[] expected = {
@@ -138,7 +138,7 @@ public class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testTypeAndVariablesAndMethodNamesWithIgnoresFinal() throws Exception {
+  void typeAndVariablesAndMethodNamesWithIgnoresFinal() throws Exception {
     final int expectedCapitalCount = 5;
 
     final String[] expected = {
@@ -155,7 +155,7 @@ public class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testTypeAndVariablesAndMethodNamesWithIgnoresStatic() throws Exception {
+  void typeAndVariablesAndMethodNamesWithIgnoresStatic() throws Exception {
     final int expectedCapitalCount = 5;
 
     final String[] expected = {
@@ -172,7 +172,7 @@ public class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testTypeAndVariablesAndMethodNamesWithIgnoresStaticFinal() throws Exception {
+  void typeAndVariablesAndMethodNamesWithIgnoresStaticFinal() throws Exception {
     final int expectedCapitalCount = 5;
 
     final String[] expected = {
@@ -190,7 +190,7 @@ public class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testTypeAndVariablesAndMethodNamesWithIgnoresNonStaticFinal() throws Exception {
+  void typeAndVariablesAndMethodNamesWithIgnoresNonStaticFinal() throws Exception {
     final int expectedCapitalCount = 5;
 
     final String[] expected = {
@@ -219,7 +219,7 @@ public class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testTypeAndVariablesAndMethodNamesWithIgnoresFinalKeepStaticFinal() throws Exception {
+  void typeAndVariablesAndMethodNamesWithIgnoresFinalKeepStaticFinal() throws Exception {
     final int expectedCapitalCount = 5;
 
     final String[] expected = {
@@ -242,8 +242,7 @@ public class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testTypeAndVariablesAndMethodNamesWithIgnoresStaticKeepStaticFinal()
-      throws Exception {
+  void typeAndVariablesAndMethodNamesWithIgnoresStaticKeepStaticFinal() throws Exception {
     final int expectedCapitalCount = 5;
 
     final String[] expected = {
@@ -266,7 +265,7 @@ public class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testTypeNamesForThreePermittedCapitalLettersWithOverriddenMethod() throws Exception {
+  void typeNamesForThreePermittedCapitalLettersWithOverriddenMethod() throws Exception {
     final int expectedCapitalCount = 4;
 
     final String[] expected = {
@@ -278,7 +277,7 @@ public class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testOverriddenMethod() throws Exception {
+  void overriddenMethod() throws Exception {
     final int expectedCapitalCount = 4;
 
     final String[] expected = {
@@ -293,7 +292,7 @@ public class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testTypeNamesForZeroPermittedCapitalLetter() throws Exception {
+  void typeNamesForZeroPermittedCapitalLetter() throws Exception {
     final int expectedCapitalCount = 1;
     final String[] expected = {
       "20:16: " + getWarningMessage("NonAAAAbstractClassName6", expectedCapitalCount),
@@ -329,7 +328,7 @@ public class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testNullPointerException() throws Exception {
+  void nullPointerException() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -338,7 +337,7 @@ public class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testAbbreviationAsWordInNameCheckEnhancedInstanceof() throws Exception {
+  void abbreviationAsWordInNameCheckEnhancedInstanceof() throws Exception {
 
     final int expectedCapitalCount = 4;
 
@@ -355,8 +354,7 @@ public class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testAbbreviationAsWordInNameCheckEnhancedInstanceofAllowXmlLength1()
-      throws Exception {
+  void abbreviationAsWordInNameCheckEnhancedInstanceofAllowXmlLength1() throws Exception {
 
     final int expectedCapitalCount = 2;
 
@@ -375,7 +373,7 @@ public class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testAbbreviationAsWordInNameCheckRecords() throws Exception {
+  void abbreviationAsWordInNameCheckRecords() throws Exception {
 
     final int expectedCapitalCount = 4;
 
@@ -406,14 +404,14 @@ public class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testReceiver() throws Exception {
+  void receiver() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputAbbreviationAsWordInNameReceiver.java"), expected);
   }
 
   @Test
-  public void testInputAbbreviationAsWordInNameTypeSnakeStyle() throws Exception {
+  void inputAbbreviationAsWordInNameTypeSnakeStyle() throws Exception {
     final String[] expected = {
       "13:20: " + getWarningMessage("FLAG_IS_FIRST_RUN", 4),
       "16:17: " + getWarningMessage("HYBRID_LOCK_PATH", 4),
@@ -431,7 +429,7 @@ public class AbbreviationAsWordInNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testAnnotation() throws Exception {
+  void annotation() throws Exception {
     final String[] expected = {
       "16:12: " + getWarningMessage("readMETHOD", 4),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/AbstractClassNameCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/AbstractClassNameCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class AbstractClassNameCheckTest extends AbstractModuleTestSupport {
+final class AbstractClassNameCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class AbstractClassNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalAbstractClassName() throws Exception {
+  void illegalAbstractClassName() throws Exception {
 
     final String pattern = "^Abstract.+$";
 
@@ -50,7 +50,7 @@ public class AbstractClassNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCustomFormat() throws Exception {
+  void customFormat() throws Exception {
 
     final String[] expected = {
       "13:1: "
@@ -68,7 +68,7 @@ public class AbstractClassNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalClassType() throws Exception {
+  void illegalClassType() throws Exception {
 
     final String[] expected = {
       "18:1: " + getCheckMessage(MSG_NO_ABSTRACT_CLASS_MODIFIER, "AbstractClassType"),
@@ -79,7 +79,7 @@ public class AbstractClassNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllVariants() throws Exception {
+  void allVariants() throws Exception {
 
     final String pattern = "^Abstract.+$";
 
@@ -99,7 +99,7 @@ public class AbstractClassNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFalsePositive() throws Exception {
+  void falsePositive() throws Exception {
     final String pattern = "^Abstract.+$";
     final String[] expected = {
       "13:1: "
@@ -118,7 +118,7 @@ public class AbstractClassNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final AbstractClassNameCheck classNameCheckObj = new AbstractClassNameCheck();
     final int[] actual = classNameCheckObj.getAcceptableTokens();
     final int[] expected = {
@@ -128,7 +128,7 @@ public class AbstractClassNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final AbstractClassNameCheck classNameCheckObj = new AbstractClassNameCheck();
     final int[] actual = classNameCheckObj.getRequiredTokens();
     final int[] expected = {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/AccessModifierOptionTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/AccessModifierOptionTest.java
@@ -23,10 +23,10 @@ import static com.google.common.truth.Truth.assertWithMessage;
 
 import org.junit.jupiter.api.Test;
 
-public class AccessModifierOptionTest {
+final class AccessModifierOptionTest {
 
   @Test
-  public void testDefaultCase() {
+  void defaultCase() {
     assertWithMessage("Case mismatch.")
         .that(AccessModifierOption.PUBLIC.name())
         .isEqualTo("PUBLIC");
@@ -42,7 +42,7 @@ public class AccessModifierOptionTest {
   }
 
   @Test
-  public void testCase() {
+  void testCase() {
     assertWithMessage("Case mismatch.")
         .that(AccessModifierOption.PUBLIC.toString())
         .isEqualTo("public");
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/CatchParameterNameCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/CatchParameterNameCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class CatchParameterNameCheckTest extends AbstractModuleTestSupport {
+final class CatchParameterNameCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class CatchParameterNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTokens() {
+  void tokens() {
     final CatchParameterNameCheck catchParameterNameCheck = new CatchParameterNameCheck();
     final int[] expected = {TokenTypes.PARAMETER_DEF};
 
@@ -48,14 +48,14 @@ public class CatchParameterNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultConfigurationOnCorrectFile() throws Exception {
+  void defaultConfigurationOnCorrectFile() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputCatchParameterNameSimple.java"), expected);
   }
 
   @Test
-  public void testDefaultConfigurationOnFileWithViolations() throws Exception {
+  void defaultConfigurationOnFileWithViolations() throws Exception {
     final String defaultFormat = "^(e|t|ex|[a-z][a-z][a-zA-Z]+)$";
 
     final String[] expected = {
@@ -73,7 +73,7 @@ public class CatchParameterNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCustomFormatFromJavadoc() throws Exception {
+  void customFormatFromJavadoc() throws Exception {
 
     final String[] expected = {
       "13:28: " + getCheckMessage(MSG_INVALID_PATTERN, "e", "^[a-z][a-zA-Z0-9]+$"),
@@ -84,7 +84,7 @@ public class CatchParameterNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCustomFormatWithNoAnchors() throws Exception {
+  void customFormatWithNoAnchors() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/ClassTypeParameterNameCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/ClassTypeParameterNameCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class ClassTypeParameterNameCheckTest extends AbstractModuleTestSupport {
+final class ClassTypeParameterNameCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class ClassTypeParameterNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetClassRequiredTokens() {
+  void getClassRequiredTokens() {
     final ClassTypeParameterNameCheck checkObj = new ClassTypeParameterNameCheck();
     final int[] expected = {TokenTypes.TYPE_PARAMETER};
     assertWithMessage("Default required tokens are invalid")
@@ -43,7 +43,7 @@ public class ClassTypeParameterNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClassDefault() throws Exception {
+  void classDefault() throws Exception {
 
     final String pattern = "^[A-Z]$";
 
@@ -56,7 +56,7 @@ public class ClassTypeParameterNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClassFooName() throws Exception {
+  void classFooName() throws Exception {
 
     final String pattern = "^foo$";
 
@@ -68,7 +68,7 @@ public class ClassTypeParameterNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final ClassTypeParameterNameCheck typeParameterNameCheckObj = new ClassTypeParameterNameCheck();
     final int[] actual = typeParameterNameCheckObj.getAcceptableTokens();
     final int[] expected = {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/ConstantNameCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/ConstantNameCheckTest.java
@@ -29,7 +29,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class ConstantNameCheckTest extends AbstractModuleTestSupport {
+final class ConstantNameCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -37,7 +37,7 @@ public class ConstantNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final ConstantNameCheck checkObj = new ConstantNameCheck();
     final int[] expected = {TokenTypes.VARIABLE_DEF};
     assertWithMessage("Default required tokens are invalid")
@@ -46,7 +46,7 @@ public class ConstantNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalRegexp() throws Exception {
+  void illegalRegexp() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(ConstantNameCheck.class);
     checkConfig.addProperty("format", "\\");
     try {
@@ -64,7 +64,7 @@ public class ConstantNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
 
     final String pattern = "^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$";
 
@@ -76,7 +76,7 @@ public class ConstantNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAccessControlTuning() throws Exception {
+  void accessControlTuning() throws Exception {
 
     final String pattern = "^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$";
 
@@ -87,7 +87,7 @@ public class ConstantNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInterfaceAndAnnotation() throws Exception {
+  void interfaceAndAnnotation() throws Exception {
 
     final String pattern = "^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$";
 
@@ -99,13 +99,13 @@ public class ConstantNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault1() throws Exception {
+  void default1() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputConstantName.java"), expected);
   }
 
   @Test
-  public void testIntoInterface() throws Exception {
+  void intoInterface() throws Exception {
 
     final String pattern = "^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$";
 
@@ -123,21 +123,21 @@ public class ConstantNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIntoInterfaceExcludePublic() throws Exception {
+  void intoInterfaceExcludePublic() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputConstantNameInterfaceIgnorePublic.java"), expected);
   }
 
   @Test
-  public void testStaticMethodInInterface() throws Exception {
+  void staticMethodInInterface() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputConstantNameStaticModifierInInterface.java"), expected);
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final ConstantNameCheck constantNameCheckObj = new ConstantNameCheck();
     final int[] actual = constantNameCheckObj.getAcceptableTokens();
     final int[] expected = {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/IllegalIdentifierNameCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/IllegalIdentifierNameCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class IllegalIdentifierNameCheckTest extends AbstractModuleTestSupport {
+final class IllegalIdentifierNameCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class IllegalIdentifierNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final IllegalIdentifierNameCheck illegalIdentifierNameCheck = new IllegalIdentifierNameCheck();
     final int[] expected = {
       TokenTypes.CLASS_DEF,
@@ -59,7 +59,7 @@ public class IllegalIdentifierNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final IllegalIdentifierNameCheck illegalIdentifierNameCheck = new IllegalIdentifierNameCheck();
     final int[] expected = CommonUtil.EMPTY_INT_ARRAY;
 
@@ -69,7 +69,7 @@ public class IllegalIdentifierNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalIdentifierNameDefault() throws Exception {
+  void illegalIdentifierNameDefault() throws Exception {
 
     final String format = "(?i)^(?!(record|yield|var|permits|sealed|_)$).+$";
 
@@ -92,7 +92,7 @@ public class IllegalIdentifierNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalIdentifierNameOpenTransitive() throws Exception {
+  void illegalIdentifierNameOpenTransitive() throws Exception {
     final String format = "(?i)^(?!(record|yield|var|permits|sealed|open|transitive)$).+$";
 
     final String[] expected = {
@@ -116,7 +116,7 @@ public class IllegalIdentifierNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalIdentifierNameParameterReceiver() throws Exception {
+  void illegalIdentifierNameParameterReceiver() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -125,7 +125,7 @@ public class IllegalIdentifierNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalIdentifierNameUnderscore() throws Exception {
+  void illegalIdentifierNameUnderscore() throws Exception {
     final String format = "(?i)^(?!(record|yield|var|permits|sealed|_)$).+$";
 
     final String[] expected = {
@@ -136,7 +136,7 @@ public class IllegalIdentifierNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalIdentifierNameLambda() throws Exception {
+  void illegalIdentifierNameLambda() throws Exception {
     final String format = "(?i)^(?!(record|yield|var|permits|sealed|_)$).+$";
 
     final String[] expected = {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/InterfaceTypeParameterNameCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/InterfaceTypeParameterNameCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class InterfaceTypeParameterNameCheckTest extends AbstractModuleTestSupport {
+final class InterfaceTypeParameterNameCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class InterfaceTypeParameterNameCheckTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final InterfaceTypeParameterNameCheck interfaceTypeParameterNameCheck =
         new InterfaceTypeParameterNameCheck();
     final int[] expected = {TokenTypes.TYPE_PARAMETER};
@@ -45,7 +45,7 @@ public class InterfaceTypeParameterNameCheckTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final InterfaceTypeParameterNameCheck checkObj = new InterfaceTypeParameterNameCheck();
     final int[] expected = {TokenTypes.TYPE_PARAMETER};
     assertWithMessage("Default required tokens are invalid")
@@ -54,7 +54,7 @@ public class InterfaceTypeParameterNameCheckTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testInterfaceDefault() throws Exception {
+  void interfaceDefault() throws Exception {
 
     final String pattern = "^[A-Z]$";
 
@@ -65,7 +65,7 @@ public class InterfaceTypeParameterNameCheckTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testInterfaceFooName() throws Exception {
+  void interfaceFooName() throws Exception {
 
     final String pattern = "^foo$";
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/LambdaParameterNameCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/LambdaParameterNameCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class LambdaParameterNameCheckTest extends AbstractModuleTestSupport {
+final class LambdaParameterNameCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class LambdaParameterNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final int[] expected = {
       TokenTypes.LAMBDA,
     };
@@ -45,7 +45,7 @@ public class LambdaParameterNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAcceptableTokens() {
+  void acceptableTokens() {
     final int[] expected = {
       TokenTypes.LAMBDA,
     };
@@ -56,7 +56,7 @@ public class LambdaParameterNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testParametersInLambda() throws Exception {
+  void parametersInLambda() throws Exception {
 
     final String pattern = "^(id)|([a-z][a-z0-9][a-zA-Z0-9]+)$";
 
@@ -71,7 +71,7 @@ public class LambdaParameterNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLambdaParameterNameSwitchExpression() throws Exception {
+  void lambdaParameterNameSwitchExpression() throws Exception {
 
     final String pattern = "^[a-z][a-zA-Z0-9]*$";
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/LocalFinalVariableNameCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/LocalFinalVariableNameCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class LocalFinalVariableNameCheckTest extends AbstractModuleTestSupport {
+final class LocalFinalVariableNameCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class LocalFinalVariableNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final LocalFinalVariableNameCheck checkObj = new LocalFinalVariableNameCheck();
     assertWithMessage(
             "LocalFinalVariableNameCheck#getRequiredTokens should return empty array "
@@ -45,7 +45,7 @@ public class LocalFinalVariableNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
 
     final String pattern = "^[a-z][a-zA-Z0-9]*$";
 
@@ -56,7 +56,7 @@ public class LocalFinalVariableNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSet() throws Exception {
+  void set() throws Exception {
 
     final String pattern = "[A-Z]+";
 
@@ -67,13 +67,13 @@ public class LocalFinalVariableNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInnerClass() throws Exception {
+  void innerClass() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputLocalFinalVariableNameInnerClass.java"), expected);
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final LocalFinalVariableNameCheck localFinalVariableNameCheckObj =
         new LocalFinalVariableNameCheck();
     final int[] actual = localFinalVariableNameCheckObj.getAcceptableTokens();
@@ -84,7 +84,7 @@ public class LocalFinalVariableNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTryWithResources() throws Exception {
+  void tryWithResources() throws Exception {
 
     final String pattern = "[A-Z]+";
 
@@ -99,7 +99,7 @@ public class LocalFinalVariableNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTryWithResourcesJava9() throws Exception {
+  void tryWithResourcesJava9() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/LocalVariableNameCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/LocalVariableNameCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class LocalVariableNameCheckTest extends AbstractModuleTestSupport {
+final class LocalVariableNameCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class LocalVariableNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final LocalVariableNameCheck localVariableNameCheck = new LocalVariableNameCheck();
     final int[] expected = {TokenTypes.VARIABLE_DEF};
 
@@ -45,7 +45,7 @@ public class LocalVariableNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
 
     final String pattern = "^[a-z][a-zA-Z0-9]*$";
 
@@ -59,13 +59,13 @@ public class LocalVariableNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInnerClass() throws Exception {
+  void innerClass() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputLocalVariableNameInnerClass.java"), expected);
   }
 
   @Test
-  public void testLoopVariables() throws Exception {
+  void loopVariables() throws Exception {
 
     final String pattern = "^[a-z]{2,}[a-zA-Z0-9]*$";
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/MemberNameCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/MemberNameCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class MemberNameCheckTest extends AbstractModuleTestSupport {
+final class MemberNameCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class MemberNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final MemberNameCheck checkObj = new MemberNameCheck();
     final int[] expected = {TokenTypes.VARIABLE_DEF};
     assertWithMessage("Default required tokens are invalid")
@@ -43,7 +43,7 @@ public class MemberNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSpecified() throws Exception {
+  void specified() throws Exception {
 
     final String pattern = "^m[A-Z][a-zA-Z0-9]*$";
 
@@ -55,7 +55,7 @@ public class MemberNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInnerClass() throws Exception {
+  void innerClass() throws Exception {
 
     final String pattern = "^[a-z][a-zA-Z0-9]*$";
 
@@ -66,7 +66,7 @@ public class MemberNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaults() throws Exception {
+  void defaults() throws Exception {
 
     final String pattern = "^[a-z][a-zA-Z0-9]*$";
 
@@ -80,7 +80,7 @@ public class MemberNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUnderlined() throws Exception {
+  void underlined() throws Exception {
 
     final String pattern = "^_[a-z]*$";
 
@@ -94,7 +94,7 @@ public class MemberNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPublicOnly() throws Exception {
+  void publicOnly() throws Exception {
 
     final String pattern = "^_[a-z]*$";
 
@@ -105,7 +105,7 @@ public class MemberNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testProtectedOnly() throws Exception {
+  void protectedOnly() throws Exception {
 
     final String pattern = "^_[a-z]*$";
 
@@ -116,7 +116,7 @@ public class MemberNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackageOnly() throws Exception {
+  void packageOnly() throws Exception {
 
     final String pattern = "^_[a-z]*$";
 
@@ -127,7 +127,7 @@ public class MemberNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPrivateOnly() throws Exception {
+  void privateOnly() throws Exception {
 
     final String pattern = "^_[a-z]*$";
 
@@ -138,7 +138,7 @@ public class MemberNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNotPrivate() throws Exception {
+  void notPrivate() throws Exception {
 
     final String pattern = "^[a-z][a-zA-Z0-9]*$";
 
@@ -151,7 +151,7 @@ public class MemberNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void memberNameExtended() throws Exception {
+  void memberNameExtended() throws Exception {
 
     final String pattern = "^[a-z][a-z0-9][a-zA-Z0-9]*$";
 
@@ -193,7 +193,7 @@ public class MemberNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final MemberNameCheck memberNameCheckObj = new MemberNameCheck();
     final int[] actual = memberNameCheckObj.getAcceptableTokens();
     final int[] expected = {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/MethodNameCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/MethodNameCheckTest.java
@@ -28,7 +28,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class MethodNameCheckTest extends AbstractModuleTestSupport {
+final class MethodNameCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -36,7 +36,7 @@ public class MethodNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final MethodNameCheck checkObj = new MethodNameCheck();
     final int[] expected = {TokenTypes.METHOD_DEF};
     assertWithMessage("Default required tokens are invalid")
@@ -45,7 +45,7 @@ public class MethodNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
 
     final String pattern = "^[a-z][a-zA-Z0-9]*$";
 
@@ -56,7 +56,7 @@ public class MethodNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMethodEqClass() throws Exception {
+  void methodEqClass() throws Exception {
 
     final String pattern = "^[a-z][a-zA-Z0-9]*$";
 
@@ -80,7 +80,7 @@ public class MethodNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMethodEqClassAllow() throws Exception {
+  void methodEqClassAllow() throws Exception {
     final String pattern = "^[a-z][a-zA-Z0-9]*$";
 
     final String[] expected = {
@@ -98,7 +98,7 @@ public class MethodNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAccessTuning() throws Exception {
+  void accessTuning() throws Exception {
     final String pattern = "^[a-z][a-zA-Z0-9]*$";
 
     final String[] expected = {
@@ -114,7 +114,7 @@ public class MethodNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testForNpe() throws Exception {
+  void forNpe() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -122,7 +122,7 @@ public class MethodNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOverriddenMethods() throws Exception {
+  void overriddenMethods() throws Exception {
 
     final String pattern = "^[a-z][a-zA-Z0-9]*$";
 
@@ -135,7 +135,7 @@ public class MethodNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInterfacesExcludePublic() throws Exception {
+  void interfacesExcludePublic() throws Exception {
     final String pattern = "^[a-z][a-zA-Z0-9]*$";
 
     final String[] expected = {
@@ -148,7 +148,7 @@ public class MethodNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInterfacesExcludePrivate() throws Exception {
+  void interfacesExcludePrivate() throws Exception {
     final String pattern = "^[a-z][a-zA-Z0-9]*$";
 
     final String[] expected = {
@@ -163,7 +163,7 @@ public class MethodNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final MethodNameCheck methodNameCheckObj = new MethodNameCheck();
     final int[] actual = methodNameCheckObj.getAcceptableTokens();
     final int[] expected = {
@@ -173,7 +173,7 @@ public class MethodNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRecordInInterfaceBody() throws Exception {
+  void recordInInterfaceBody() throws Exception {
 
     final String pattern = "^[a-z][a-zA-Z0-9]*$";
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/MethodTypeParameterNameCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/MethodTypeParameterNameCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class MethodTypeParameterNameCheckTest extends AbstractModuleTestSupport {
+final class MethodTypeParameterNameCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class MethodTypeParameterNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final MethodTypeParameterNameCheck methodTypeParameterNameCheck =
         new MethodTypeParameterNameCheck();
     final int[] expected = {TokenTypes.TYPE_PARAMETER};
@@ -45,7 +45,7 @@ public class MethodTypeParameterNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final MethodTypeParameterNameCheck checkObj = new MethodTypeParameterNameCheck();
     final int[] expected = {TokenTypes.TYPE_PARAMETER};
     assertWithMessage("Default required tokens are invalid")
@@ -54,7 +54,7 @@ public class MethodTypeParameterNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testMethodDefault() throws Exception {
+  void methodDefault() throws Exception {
 
     final String pattern = "^[A-Z]$";
 
@@ -69,7 +69,7 @@ public class MethodTypeParameterNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testMethodFooName() throws Exception {
+  void methodFooName() throws Exception {
 
     final String pattern = "^foo$";
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/PackageNameCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/PackageNameCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class PackageNameCheckTest extends AbstractModuleTestSupport {
+final class PackageNameCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class PackageNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final PackageNameCheck checkObj = new PackageNameCheck();
     final int[] expected = {TokenTypes.PACKAGE_DEF};
     assertWithMessage("Default required tokens are invalid")
@@ -44,7 +44,7 @@ public class PackageNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSpecified() throws Exception {
+  void specified() throws Exception {
 
     final String pattern = "[A-Z]+";
 
@@ -57,13 +57,13 @@ public class PackageNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputPackageNameSimple.java"), expected);
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final PackageNameCheck packageNameCheckObj = new PackageNameCheck();
     final int[] actual = packageNameCheckObj.getAcceptableTokens();
     final int[] expected = {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/ParameterNameCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/ParameterNameCheckTest.java
@@ -28,7 +28,7 @@ import com.puppycrawl.tools.checkstyle.internal.utils.TestUtil;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class ParameterNameCheckTest extends AbstractModuleTestSupport {
+final class ParameterNameCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -36,7 +36,7 @@ public class ParameterNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final ParameterNameCheck checkObj = new ParameterNameCheck();
     final int[] expected = {TokenTypes.PARAMETER_DEF};
     assertWithMessage("Default required tokens are invalid")
@@ -45,13 +45,13 @@ public class ParameterNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCatch() throws Exception {
+  void testCatch() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputParameterNameCatchOnly.java"), expected);
   }
 
   @Test
-  public void testSpecified() throws Exception {
+  void specified() throws Exception {
 
     final String pattern = "^a[A-Z][a-zA-Z0-9]*$";
 
@@ -64,7 +64,7 @@ public class ParameterNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWhitespaceInAccessModifierProperty() throws Exception {
+  void whitespaceInAccessModifierProperty() throws Exception {
     final String pattern = "^h$";
     final String[] expected = {
       "14:69: " + getCheckMessage(MSG_INVALID_PATTERN, "parameter1", pattern),
@@ -75,13 +75,13 @@ public class ParameterNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputParameterName.java"), expected);
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final ParameterNameCheck parameterNameCheckObj = new ParameterNameCheck();
     final int[] actual = parameterNameCheckObj.getAcceptableTokens();
     final int[] expected = {
@@ -91,7 +91,7 @@ public class ParameterNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSkipMethodsWithOverrideAnnotationTrue() throws Exception {
+  void skipMethodsWithOverrideAnnotationTrue() throws Exception {
 
     final String pattern = "^h$";
 
@@ -108,7 +108,7 @@ public class ParameterNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSkipMethodsWithOverrideAnnotationFalse() throws Exception {
+  void skipMethodsWithOverrideAnnotationFalse() throws Exception {
 
     final String pattern = "^h$";
 
@@ -126,7 +126,7 @@ public class ParameterNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPublicAccessModifier() throws Exception {
+  void publicAccessModifier() throws Exception {
 
     final String pattern = "^h$";
 
@@ -142,32 +142,32 @@ public class ParameterNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIsOverriddenNoNullPointerException() throws Exception {
+  void isOverriddenNoNullPointerException() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputParameterNameOverrideAnnotationNoNPE.java"), expected);
   }
 
   @Test
-  public void testReceiverParameter() throws Exception {
+  void receiverParameter() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputParameterNameReceiver.java"), expected);
   }
 
   @Test
-  public void testLambdaParameterNoViolationAtAll() throws Exception {
+  void lambdaParameterNoViolationAtAll() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputParameterNameLambda.java"), expected);
   }
 
   @Test
-  public void testWhitespaceInConfig() throws Exception {
+  void whitespaceInConfig() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputParameterNameWhitespaceInConfig.java"), expected);
   }
 
   @Test
-  public void testSetAccessModifiers() throws Exception {
+  void setAccessModifiers() throws Exception {
     final AccessModifierOption[] input = {
       AccessModifierOption.PACKAGE,
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/PatternVariableNameCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/PatternVariableNameCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class PatternVariableNameCheckTest extends AbstractModuleTestSupport {
+final class PatternVariableNameCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class PatternVariableNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final PatternVariableNameCheck patternVariableNameCheck = new PatternVariableNameCheck();
     final int[] expected = {TokenTypes.PATTERN_VARIABLE_DEF};
 
@@ -44,7 +44,7 @@ public class PatternVariableNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
 
     final String pattern = "^[a-z][a-zA-Z0-9]*$";
 
@@ -65,7 +65,7 @@ public class PatternVariableNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPatternVariableNameNoSingleChar() throws Exception {
+  void patternVariableNameNoSingleChar() throws Exception {
 
     final String pattern = "^[a-z][a-zA-Z0-9]+$";
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/RecordComponentNameCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/RecordComponentNameCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class RecordComponentNameCheckTest extends AbstractModuleTestSupport {
+final class RecordComponentNameCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class RecordComponentNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetClassRequiredTokens() {
+  void getClassRequiredTokens() {
     final RecordComponentNameCheck checkObj = new RecordComponentNameCheck();
     final int[] expected = {TokenTypes.RECORD_COMPONENT_DEF};
     assertWithMessage("Default required tokens are invalid")
@@ -43,7 +43,7 @@ public class RecordComponentNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRecordDefault() throws Exception {
+  void recordDefault() throws Exception {
 
     final String pattern = "^[a-z][a-zA-Z0-9]*$";
 
@@ -58,7 +58,7 @@ public class RecordComponentNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClassFooName() throws Exception {
+  void classFooName() throws Exception {
 
     final String pattern = "^[a-z0-9]+$";
 
@@ -73,7 +73,7 @@ public class RecordComponentNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final RecordComponentNameCheck typeParameterNameCheckObj = new RecordComponentNameCheck();
     final int[] actual = typeParameterNameCheckObj.getAcceptableTokens();
     final int[] expected = {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/RecordTypeParameterNameCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/RecordTypeParameterNameCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class RecordTypeParameterNameCheckTest extends AbstractModuleTestSupport {
+final class RecordTypeParameterNameCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class RecordTypeParameterNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testGetClassRequiredTokens() {
+  void getClassRequiredTokens() {
     final RecordTypeParameterNameCheck checkObj = new RecordTypeParameterNameCheck();
     final int[] expected = {TokenTypes.TYPE_PARAMETER};
     assertWithMessage("Default required tokens are invalid")
@@ -43,7 +43,7 @@ public class RecordTypeParameterNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testRecordDefault() throws Exception {
+  void recordDefault() throws Exception {
 
     final String pattern = "^[A-Z]$";
 
@@ -57,7 +57,7 @@ public class RecordTypeParameterNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testClassFooName() throws Exception {
+  void classFooName() throws Exception {
 
     final String pattern = "^foo$";
 
@@ -71,7 +71,7 @@ public class RecordTypeParameterNameCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final RecordTypeParameterNameCheck typeParameterNameCheckObj =
         new RecordTypeParameterNameCheck();
     final int[] actual = typeParameterNameCheckObj.getAcceptableTokens();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/StaticVariableNameCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/StaticVariableNameCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class StaticVariableNameCheckTest extends AbstractModuleTestSupport {
+final class StaticVariableNameCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class StaticVariableNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final StaticVariableNameCheck checkObj = new StaticVariableNameCheck();
     final int[] expected = {TokenTypes.VARIABLE_DEF};
     assertWithMessage("Default required tokens are invalid")
@@ -44,7 +44,7 @@ public class StaticVariableNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSpecified() throws Exception {
+  void specified() throws Exception {
 
     final String pattern = "^s[A-Z][a-zA-Z0-9]*$";
 
@@ -55,19 +55,19 @@ public class StaticVariableNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAccessTuning() throws Exception {
+  void accessTuning() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputStaticVariableName2.java"), expected);
   }
 
   @Test
-  public void testInterfaceOrAnnotationBlock() throws Exception {
+  void interfaceOrAnnotationBlock() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputStaticVariableName.java"), expected);
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final StaticVariableNameCheck staticVariableNameCheckObj = new StaticVariableNameCheck();
     final int[] actual = staticVariableNameCheckObj.getAcceptableTokens();
     final int[] expected = {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/TypeNameCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/naming/TypeNameCheckTest.java
@@ -25,7 +25,7 @@ import static com.puppycrawl.tools.checkstyle.checks.naming.TypeNameCheck.DEFAUL
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class TypeNameCheckTest extends AbstractModuleTestSupport {
+final class TypeNameCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class TypeNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSpecified() throws Exception {
+  void specified() throws Exception {
     final String[] expected = {
       "25:14: " + getCheckMessage(MSG_INVALID_PATTERN, "InputTypeName", "^inputHe"),
     };
@@ -41,7 +41,7 @@ public class TypeNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "15:7: " + getCheckMessage(MSG_INVALID_PATTERN, "inputHeaderClass2", DEFAULT_PATTERN),
       "17:22: " + getCheckMessage(MSG_INVALID_PATTERN, "inputHeaderInterface", DEFAULT_PATTERN),
@@ -52,7 +52,7 @@ public class TypeNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClassSpecific() throws Exception {
+  void classSpecific() throws Exception {
     final String[] expected = {
       "15:7: " + getCheckMessage(MSG_INVALID_PATTERN, "inputHeaderClass3", DEFAULT_PATTERN),
     };
@@ -60,7 +60,7 @@ public class TypeNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInterfaceSpecific() throws Exception {
+  void interfaceSpecific() throws Exception {
     final String[] expected = {
       "17:22: " + getCheckMessage(MSG_INVALID_PATTERN, "inputHeaderInterface", DEFAULT_PATTERN),
     };
@@ -68,7 +68,7 @@ public class TypeNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEnumSpecific() throws Exception {
+  void enumSpecific() throws Exception {
     final String[] expected = {
       "19:17: " + getCheckMessage(MSG_INVALID_PATTERN, "inputHeaderEnum", DEFAULT_PATTERN),
     };
@@ -76,7 +76,7 @@ public class TypeNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationSpecific() throws Exception {
+  void annotationSpecific() throws Exception {
     final String[] expected = {
       "21:23: " + getCheckMessage(MSG_INVALID_PATTERN, "inputHeaderAnnotation", DEFAULT_PATTERN),
     };
@@ -84,7 +84,7 @@ public class TypeNameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTypeNameRecords() throws Exception {
+  void typeNameRecords() throws Exception {
 
     final String[] expected = {
       "23:10: " + getCheckMessage(MSG_INVALID_PATTERN, "Third_Name", DEFAULT_PATTERN),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpCheckTest.java
@@ -24,12 +24,13 @@ import static com.puppycrawl.tools.checkstyle.checks.regexp.RegexpCheck.MSG_DUPL
 import static com.puppycrawl.tools.checkstyle.checks.regexp.RegexpCheck.MSG_ILLEGAL_REGEXP;
 import static com.puppycrawl.tools.checkstyle.checks.regexp.RegexpCheck.MSG_REQUIRED_REGEXP;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class RegexpCheckTest extends AbstractModuleTestSupport {
+final class RegexpCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -37,7 +38,7 @@ public class RegexpCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final RegexpCheck regexpCheck = new RegexpCheck();
     assertWithMessage("RegexpCheck#getAcceptableTokens should return empty array by default")
         .that(regexpCheck.getAcceptableTokens())
@@ -45,7 +46,7 @@ public class RegexpCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final RegexpCheck checkObj = new RegexpCheck();
     assertWithMessage("RegexpCheck#getRequiredTokens should return empty array by default")
         .that(checkObj.getRequiredTokens())
@@ -53,13 +54,13 @@ public class RegexpCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRequiredPass() throws Exception {
+  void requiredPass() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRegexpSemantic.java"), expected);
   }
 
   @Test
-  public void testRequiredFail() throws Exception {
+  void requiredFail() throws Exception {
     final String[] expected = {
       "1: " + getCheckMessage(MSG_REQUIRED_REGEXP, "This\\stext is not in the file"),
     };
@@ -67,25 +68,25 @@ public class RegexpCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRegexpCheckDefault.java"), expected);
   }
 
   @Test
-  public void testRequiredNoDuplicatesPass() throws Exception {
+  void requiredNoDuplicatesPass() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRegexpSemantic3.java"), expected);
   }
 
   @Test
-  public void testSetDuplicatesTrue() throws Exception {
+  void setDuplicatesTrue() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRegexpSemantic4.java"), expected);
   }
 
   @Test
-  public void testRequiredNoDuplicatesFail() throws Exception {
+  void requiredNoDuplicatesFail() throws Exception {
     final String[] expected = {
       "27: " + getCheckMessage(MSG_DUPLICATE_REGEXP, "Boolean x = new Boolean"),
       "32: " + getCheckMessage(MSG_DUPLICATE_REGEXP, "Boolean x = new Boolean"),
@@ -94,19 +95,19 @@ public class RegexpCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalPass() throws Exception {
+  void illegalPass() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRegexpSemantic6.java"), expected);
   }
 
   @Test
-  public void testStopEarly() throws Exception {
+  void stopEarly() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRegexpCheckStopEarly.java"), expected);
   }
 
   @Test
-  public void testIllegalFailBelowErrorLimit() throws Exception {
+  void illegalFailBelowErrorLimit() throws Exception {
     final String[] expected = {
       "15: " + getCheckMessage(MSG_ILLEGAL_REGEXP, "^import"),
       "16: " + getCheckMessage(MSG_ILLEGAL_REGEXP, "^import"),
@@ -116,7 +117,7 @@ public class RegexpCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIllegalFailAboveErrorLimit() throws Exception {
+  void illegalFailAboveErrorLimit() throws Exception {
     final String error =
         "The error limit has been exceeded, "
             + "the check is aborting, there may be more unreported errors.";
@@ -128,7 +129,7 @@ public class RegexpCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMessagePropertyGood() throws Exception {
+  void messagePropertyGood() throws Exception {
     final String[] expected = {
       "78: " + getCheckMessage(MSG_ILLEGAL_REGEXP, "Bad line :("),
     };
@@ -136,7 +137,7 @@ public class RegexpCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMessagePropertyBad() throws Exception {
+  void messagePropertyBad() throws Exception {
     final String[] expected = {
       "78: " + getCheckMessage(MSG_ILLEGAL_REGEXP, "System\\.(out)|(err)\\.print(ln)?\\("),
     };
@@ -144,7 +145,7 @@ public class RegexpCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMessagePropertyBad2() throws Exception {
+  void messagePropertyBad2() throws Exception {
     final String[] expected = {
       "78: " + getCheckMessage(MSG_ILLEGAL_REGEXP, "System\\.(out)|(err)\\.print(ln)?\\("),
     };
@@ -152,7 +153,7 @@ public class RegexpCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreCaseTrue() throws Exception {
+  void ignoreCaseTrue() throws Exception {
     final String[] expected = {
       "78: " + getCheckMessage(MSG_ILLEGAL_REGEXP, "(?i)SYSTEM\\.(OUT)|(ERR)\\.PRINT(LN)?\\("),
     };
@@ -160,7 +161,7 @@ public class RegexpCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreCaseFalse() throws Exception {
+  void ignoreCaseFalse() throws Exception {
     final String[] expectedTrue = {
       "78: " + getCheckMessage(MSG_ILLEGAL_REGEXP, "(?i)SYSTEM\\.(OUT)|(ERR)\\.PRINT(LN)?\\("),
     };
@@ -171,14 +172,14 @@ public class RegexpCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreCommentsCppStyle() throws Exception {
+  void ignoreCommentsCppStyle() throws Exception {
     // See if the comment is removed properly
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRegexpTrailingComment.java"), expected);
   }
 
   @Test
-  public void testIgnoreCommentsFalseCppStyle() throws Exception {
+  void ignoreCommentsFalseCppStyle() throws Exception {
     // See if the comment is removed properly
     final String[] expected = {
       "16: " + getCheckMessage(MSG_ILLEGAL_REGEXP, "don't\\suse trailing comments"),
@@ -187,14 +188,14 @@ public class RegexpCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreCommentsBlockStyle() throws Exception {
+  void ignoreCommentsBlockStyle() throws Exception {
     // See if the comment is removed properly
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRegexpTrailingComment3.java"), expected);
   }
 
   @Test
-  public void testIgnoreCommentsFalseBlockStyle() throws Exception {
+  void ignoreCommentsFalseBlockStyle() throws Exception {
     final String[] expected = {
       "31: " + getCheckMessage(MSG_ILLEGAL_REGEXP, "c-style\\s1"),
     };
@@ -202,26 +203,26 @@ public class RegexpCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreCommentsMultipleBlockStyle() throws Exception {
+  void ignoreCommentsMultipleBlockStyle() throws Exception {
     // See if a second comment on the same line is removed properly
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRegexpTrailingComment5.java"), expected);
   }
 
   @Test
-  public void testIgnoreCommentsMultiLine() throws Exception {
+  void ignoreCommentsMultiLine() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRegexpTrailingComment6.java"), expected);
   }
 
   @Test
-  public void testIgnoreCommentsInlineStart() throws Exception {
+  void ignoreCommentsInlineStart() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRegexpTrailingComment7.java"), expected);
   }
 
   @Test
-  public void testIgnoreCommentsInlineEnd() throws Exception {
+  void ignoreCommentsInlineEnd() throws Exception {
     final String[] expected = {
       "34: " + getCheckMessage(MSG_ILLEGAL_REGEXP, "int z"),
     };
@@ -229,7 +230,7 @@ public class RegexpCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreCommentsInlineMiddle() throws Exception {
+  void ignoreCommentsInlineMiddle() throws Exception {
     final String[] expected = {
       "35: " + getCheckMessage(MSG_ILLEGAL_REGEXP, "int y"),
     };
@@ -237,20 +238,20 @@ public class RegexpCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreCommentsNoSpaces() throws Exception {
+  void ignoreCommentsNoSpaces() throws Exception {
     // make sure the comment is not turned into spaces
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRegexpTrailingComment10.java"), expected);
   }
 
   @Test
-  public void testOnFileStartingWithEmptyLine() throws Exception {
+  void onFileStartingWithEmptyLine() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRegexpStartingWithEmptyLine.java"), expected);
   }
 
   @Test
-  public void testIgnoreCommentsCppStyleWithIllegalPatternFalse() throws Exception {
+  void ignoreCommentsCppStyleWithIllegalPatternFalse() throws Exception {
     // See if the comment is removed properly
     final String[] expected = {
       "1: " + getCheckMessage(MSG_REQUIRED_REGEXP, "don't use trailing comments"),
@@ -259,18 +260,18 @@ public class RegexpCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStateIsClearedOnBeginTreeErrorCount() throws Exception {
+  void stateIsClearedOnBeginTreeErrorCount() throws Exception {
     final String file1 = getPath("InputRegexpCheckB2.java");
     final String file2 = getPath("InputRegexpCheckB1.java");
     final List<String> expectedFromFile1 =
-        List.of("12: " + getCheckMessage(MSG_ILLEGAL_REGEXP, "^import"));
+        ImmutableList.of("12: " + getCheckMessage(MSG_ILLEGAL_REGEXP, "^import"));
     final List<String> expectedFromFile2 =
-        List.of("12: " + getCheckMessage(MSG_ILLEGAL_REGEXP, "^import"));
+        ImmutableList.of("12: " + getCheckMessage(MSG_ILLEGAL_REGEXP, "^import"));
     verifyWithInlineConfigParser(file1, file2, expectedFromFile1, expectedFromFile2);
   }
 
   @Test
-  public void testStateIsClearedOnBeginTreeMatchCount() throws Exception {
+  void stateIsClearedOnBeginTreeMatchCount() throws Exception {
     final String file1 = getPath("InputRegexpCheckB3.java");
     final String file2 = getPath("InputRegexpCheckB4.java");
     final List<String> expectedFirstInput = List.of(CommonUtil.EMPTY_STRING_ARRAY);
@@ -279,7 +280,7 @@ public class RegexpCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOnFileStartingWithEmptyLine2() throws Exception {
+  void onFileStartingWithEmptyLine2() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRegexpCheckEmptyLine2.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpMultilineCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpMultilineCheckTest.java
@@ -24,6 +24,7 @@ import static com.puppycrawl.tools.checkstyle.checks.regexp.MultilineDetector.MS
 import static com.puppycrawl.tools.checkstyle.checks.regexp.MultilineDetector.MSG_REGEXP_EXCEEDED;
 import static com.puppycrawl.tools.checkstyle.checks.regexp.MultilineDetector.MSG_REGEXP_MINIMUM;
 import static com.puppycrawl.tools.checkstyle.checks.regexp.MultilineDetector.MSG_STACKOVERFLOW;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
@@ -36,7 +37,7 @@ import java.nio.file.Files;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
 
-public class RegexpMultilineCheckTest extends AbstractModuleTestSupport {
+final class RegexpMultilineCheckTest extends AbstractModuleTestSupport {
 
   @TempDir public File temporaryFolder;
 
@@ -46,7 +47,7 @@ public class RegexpMultilineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIt() throws Exception {
+  void it() throws Exception {
     final String[] expected = {
       "78: " + getCheckMessage(MSG_REGEXP_EXCEEDED, "System\\.(out)|(err)\\.print(ln)?\\("),
     };
@@ -54,7 +55,7 @@ public class RegexpMultilineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMessageProperty() throws Exception {
+  void messageProperty() throws Exception {
     final String[] expected = {
       "79: " + "Bad line :(",
     };
@@ -62,7 +63,7 @@ public class RegexpMultilineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreCaseTrue() throws Exception {
+  void ignoreCaseTrue() throws Exception {
     final String[] expected = {
       "79: " + getCheckMessage(MSG_REGEXP_EXCEEDED, "SYSTEM\\.(OUT)|(ERR)\\.PRINT(LN)?\\("),
     };
@@ -70,13 +71,13 @@ public class RegexpMultilineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreCaseFalse() throws Exception {
+  void ignoreCaseFalse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRegexpMultilineSemantic4.java"), expected);
   }
 
   @Test
-  public void testIllegalFailBelowErrorLimit() throws Exception {
+  void illegalFailBelowErrorLimit() throws Exception {
     final String[] expected = {
       "16: " + getCheckMessage(MSG_REGEXP_EXCEEDED, "^import"),
       "17: " + getCheckMessage(MSG_REGEXP_EXCEEDED, "^import"),
@@ -86,7 +87,7 @@ public class RegexpMultilineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCarriageReturn() throws Exception {
+  void carriageReturn() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpMultilineCheck.class);
     checkConfig.addProperty("format", "\\r");
     checkConfig.addProperty("maximum", "0");
@@ -96,15 +97,13 @@ public class RegexpMultilineCheckTest extends AbstractModuleTestSupport {
     };
 
     final File file = File.createTempFile("junit", null, temporaryFolder);
-    Files.write(
-        file.toPath(),
-        "first line \r\n second line \n\r third line".getBytes(StandardCharsets.UTF_8));
+    Files.write(file.toPath(), "first line \r\n second line \n\r third line".getBytes(UTF_8));
 
     verify(checkConfig, file.getPath(), expected);
   }
 
   @Test
-  public void testMaximum() throws Exception {
+  void maximum() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpMultilineCheck.class);
     checkConfig.addProperty("format", "\\r");
     checkConfig.addProperty("maximum", "1");
@@ -113,9 +112,7 @@ public class RegexpMultilineCheckTest extends AbstractModuleTestSupport {
     };
 
     final File file = File.createTempFile("junit", null, temporaryFolder);
-    Files.write(
-        file.toPath(),
-        "first line \r\n second line \n\r third line".getBytes(StandardCharsets.UTF_8));
+    Files.write(file.toPath(), "first line \r\n second line \n\r third line".getBytes(UTF_8));
 
     verify(checkConfig, file.getPath(), expected);
   }
@@ -126,16 +123,14 @@ public class RegexpMultilineCheckTest extends AbstractModuleTestSupport {
    * @throws Exception some Exception
    */
   @Test
-  public void testStateIsBeingReset() throws Exception {
+  void stateIsBeingReset() throws Exception {
     final TestLoggingReporter reporter = new TestLoggingReporter();
     final DetectorOptions detectorOptions =
         DetectorOptions.newBuilder().reporter(reporter).format("\\r").maximum(1).build();
 
     final MultilineDetector detector = new MultilineDetector(detectorOptions);
     final File file = File.createTempFile("junit", null, temporaryFolder);
-    Files.write(
-        file.toPath(),
-        "first line \r\n second line \n\r third line".getBytes(StandardCharsets.UTF_8));
+    Files.write(file.toPath(), "first line \r\n second line \n\r third line".getBytes(UTF_8));
 
     detector.processLines(new FileText(file, StandardCharsets.UTF_8.name()));
     detector.processLines(new FileText(file, StandardCharsets.UTF_8.name()));
@@ -145,13 +140,13 @@ public class RegexpMultilineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultConfiguration() throws Exception {
+  void defaultConfiguration() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRegexpMultilineSemantic6.java"), expected);
   }
 
   @Test
-  public void testNullFormat() throws Exception {
+  void nullFormat() throws Exception {
     final String[] expected = {
       "1: " + getCheckMessage(MSG_EMPTY),
     };
@@ -159,7 +154,7 @@ public class RegexpMultilineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyFormat() throws Exception {
+  void emptyFormat() throws Exception {
     final String[] expected = {
       "1: " + getCheckMessage(MSG_EMPTY),
     };
@@ -167,7 +162,7 @@ public class RegexpMultilineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoStackOverflowError() throws Exception {
+  void noStackOverflowError() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpMultilineCheck.class);
     // http://madbean.com/2004/mb2004-20/
     checkConfig.addProperty("format", "(x|y)*");
@@ -177,13 +172,13 @@ public class RegexpMultilineCheckTest extends AbstractModuleTestSupport {
     };
 
     final File file = File.createTempFile("junit", null, temporaryFolder);
-    Files.write(file.toPath(), makeLargeXyString().toString().getBytes(StandardCharsets.UTF_8));
+    Files.write(file.toPath(), makeLargeXyString().toString().getBytes(UTF_8));
 
     verify(checkConfig, file.getPath(), expected);
   }
 
   @Test
-  public void testMinimum() throws Exception {
+  void minimum() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpMultilineCheck.class);
     checkConfig.addProperty("format", "\\r");
     checkConfig.addProperty("minimum", "5");
@@ -192,13 +187,13 @@ public class RegexpMultilineCheckTest extends AbstractModuleTestSupport {
     };
 
     final File file = File.createTempFile("junit", null, temporaryFolder);
-    Files.write(file.toPath(), "".getBytes(StandardCharsets.UTF_8));
+    Files.write(file.toPath(), "".getBytes(UTF_8));
 
     verify(checkConfig, file.getPath(), expected);
   }
 
   @Test
-  public void testMinimumWithCustomMessage() throws Exception {
+  void minimumWithCustomMessage() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpMultilineCheck.class);
     checkConfig.addProperty("format", "\\r");
     checkConfig.addProperty("minimum", "5");
@@ -208,7 +203,7 @@ public class RegexpMultilineCheckTest extends AbstractModuleTestSupport {
     };
 
     final File file = File.createTempFile("junit", null, temporaryFolder);
-    Files.write(file.toPath(), "".getBytes(StandardCharsets.UTF_8));
+    Files.write(file.toPath(), "".getBytes(UTF_8));
 
     verify(checkConfig, file.getPath(), expected);
   }
@@ -221,13 +216,13 @@ public class RegexpMultilineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGoodLimit() throws Exception {
+  void goodLimit() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRegexpMultilineSemantic9.java"), expected);
   }
 
   @Test
-  public void testMultilineSupport() throws Exception {
+  void multilineSupport() throws Exception {
     final String[] expected = {
       "22: " + getCheckMessage(MSG_REGEXP_EXCEEDED, "(a)bc.*def"),
     };
@@ -235,7 +230,7 @@ public class RegexpMultilineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMultilineSupportNotGreedy() throws Exception {
+  void multilineSupportNotGreedy() throws Exception {
     final String[] expected = {
       "22: " + getCheckMessage(MSG_REGEXP_EXCEEDED, "(a)bc.*?def"),
       "24: " + getCheckMessage(MSG_REGEXP_EXCEEDED, "(a)bc.*?def"),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpOnFilenameCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpOnFilenameCheckTest.java
@@ -24,17 +24,17 @@ import static com.puppycrawl.tools.checkstyle.checks.regexp.RegexpOnFilenameChec
 import static com.puppycrawl.tools.checkstyle.checks.regexp.RegexpOnFilenameCheck.MSG_MISMATCH;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
 import com.puppycrawl.tools.checkstyle.api.FileText;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.io.File;
-import java.util.Collections;
 import java.util.regex.Pattern;
 import org.junit.jupiter.api.Test;
 
-public class RegexpOnFilenameCheckTest extends AbstractModuleTestSupport {
+final class RegexpOnFilenameCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -42,14 +42,14 @@ public class RegexpOnFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultConfigurationOnValidInput() throws Exception {
+  void defaultConfigurationOnValidInput() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpOnFilenameCheck.class);
     verify(
         checkConfig, getPath("InputRegexpOnFilenameSemantic.java"), CommonUtil.EMPTY_STRING_ARRAY);
   }
 
   @Test
-  public void testDefaultProperties() throws Exception {
+  void defaultProperties() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpOnFilenameCheck.class);
     final String path = getPath("InputRegexpOnFilename Space.properties");
     final String[] expected = {
@@ -59,7 +59,7 @@ public class RegexpOnFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMatchFileMatches() throws Exception {
+  void matchFileMatches() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpOnFilenameCheck.class);
     checkConfig.addProperty("match", "true");
     checkConfig.addProperty("fileNamePattern", ".*\\.java");
@@ -71,7 +71,7 @@ public class RegexpOnFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMatchFileNotMatches() throws Exception {
+  void matchFileNotMatches() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpOnFilenameCheck.class);
     checkConfig.addProperty("match", "true");
     checkConfig.addProperty("fileNamePattern", "BAD.*");
@@ -80,7 +80,7 @@ public class RegexpOnFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNotMatchFileMatches() throws Exception {
+  void notMatchFileMatches() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpOnFilenameCheck.class);
     checkConfig.addProperty("match", "false");
     checkConfig.addProperty("fileNamePattern", ".*\\.properties");
@@ -92,7 +92,7 @@ public class RegexpOnFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNotMatchFileNotMatches() throws Exception {
+  void notMatchFileNotMatches() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpOnFilenameCheck.class);
     checkConfig.addProperty("match", "false");
     checkConfig.addProperty("fileNamePattern", ".*\\.java");
@@ -101,7 +101,7 @@ public class RegexpOnFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMatchFolderMatches() throws Exception {
+  void matchFolderMatches() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpOnFilenameCheck.class);
     checkConfig.addProperty("match", "true");
     checkConfig.addProperty("folderPattern", ".*[\\\\/]resources[\\\\/].*");
@@ -113,7 +113,7 @@ public class RegexpOnFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMatchFolderNotMatches() throws Exception {
+  void matchFolderNotMatches() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpOnFilenameCheck.class);
     checkConfig.addProperty("match", "true");
     checkConfig.addProperty("folderPattern", "BAD.*");
@@ -122,7 +122,7 @@ public class RegexpOnFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNotMatchFolderMatches() throws Exception {
+  void notMatchFolderMatches() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpOnFilenameCheck.class);
     checkConfig.addProperty("match", "false");
     checkConfig.addProperty("folderPattern", ".*[\\\\/]gov[\\\\/].*");
@@ -134,7 +134,7 @@ public class RegexpOnFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNotMatchFolderNotMatches() throws Exception {
+  void notMatchFolderNotMatches() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpOnFilenameCheck.class);
     checkConfig.addProperty("match", "false");
     checkConfig.addProperty("folderPattern", ".*[\\\\/]resources[\\\\/].*");
@@ -143,7 +143,7 @@ public class RegexpOnFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMatchFolderAndFileMatches() throws Exception {
+  void matchFolderAndFileMatches() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpOnFilenameCheck.class);
     checkConfig.addProperty("match", "true");
     checkConfig.addProperty("folderPattern", ".*[\\\\/]resources[\\\\/].*");
@@ -156,7 +156,7 @@ public class RegexpOnFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMatchFolderAndFileNotMatchesBoth() throws Exception {
+  void matchFolderAndFileNotMatchesBoth() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpOnFilenameCheck.class);
     checkConfig.addProperty("match", "true");
     checkConfig.addProperty("folderPattern", "BAD.*");
@@ -166,7 +166,7 @@ public class RegexpOnFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMatchFolderAndFileNotMatchesFile() throws Exception {
+  void matchFolderAndFileNotMatchesFile() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpOnFilenameCheck.class);
     checkConfig.addProperty("match", "true");
     checkConfig.addProperty("folderPattern", ".*[\\\\/]resources[\\\\/].*");
@@ -176,7 +176,7 @@ public class RegexpOnFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMatchFolderAndFileNotMatchesFolder() throws Exception {
+  void matchFolderAndFileNotMatchesFolder() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpOnFilenameCheck.class);
     checkConfig.addProperty("match", "true");
     checkConfig.addProperty("folderPattern", "BAD.*");
@@ -186,7 +186,7 @@ public class RegexpOnFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNotMatchFolderAndFileMatches() throws Exception {
+  void notMatchFolderAndFileMatches() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpOnFilenameCheck.class);
     checkConfig.addProperty("match", "false");
     checkConfig.addProperty("folderPattern", ".*[\\\\/]com[\\\\/].*");
@@ -199,7 +199,7 @@ public class RegexpOnFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNotMatchFolderAndFileNotMatchesFolder() throws Exception {
+  void notMatchFolderAndFileNotMatchesFolder() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpOnFilenameCheck.class);
     checkConfig.addProperty("match", "false");
     checkConfig.addProperty("folderPattern", ".*[\\\\/]javastrangefolder[\\\\/].*");
@@ -209,7 +209,7 @@ public class RegexpOnFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNotMatchFolderAndFileNotMatchesFile() throws Exception {
+  void notMatchFolderAndFileNotMatchesFile() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpOnFilenameCheck.class);
     checkConfig.addProperty("match", "false");
     checkConfig.addProperty("folderPattern", ".*[\\\\/]govstrangefolder[\\\\/].*");
@@ -219,7 +219,7 @@ public class RegexpOnFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreExtension() throws Exception {
+  void ignoreExtension() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpOnFilenameCheck.class);
     checkConfig.addProperty("fileNamePattern", ".*\\.java");
     checkConfig.addProperty("ignoreFileNameExtensions", "true");
@@ -228,7 +228,7 @@ public class RegexpOnFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreExtensionNoExtension() throws Exception {
+  void ignoreExtensionNoExtension() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(RegexpOnFilenameCheck.class);
     checkConfig.addProperty("fileNamePattern", "\\.");
     checkConfig.addProperty("ignoreFileNameExtensions", "true");
@@ -236,7 +236,7 @@ public class RegexpOnFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testException() throws Exception {
+  void exception() throws Exception {
     // escape character needed for testing IOException from File.getCanonicalPath on all OSes
     final File file = new File(getPath("") + "\u0000" + File.separatorChar + "Test");
     final RegexpOnFilenameCheck check = new RegexpOnFilenameCheck();
@@ -244,7 +244,7 @@ public class RegexpOnFilenameCheckTest extends AbstractModuleTestSupport {
     final CheckstyleException ex =
         assertThrows(
             CheckstyleException.class,
-            () -> check.process(file, new FileText(file, Collections.emptyList())),
+            () -> check.process(file, new FileText(file, ImmutableList.of())),
             "CheckstyleException expected");
     assertWithMessage("Invalid exception message")
         .that(ex)
@@ -253,7 +253,7 @@ public class RegexpOnFilenameCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithFileWithoutParent() throws Exception {
+  void withFileWithoutParent() throws Exception {
     final DefaultConfiguration moduleConfig = createModuleConfig(RegexpOnFilenameCheck.class);
     final String path = getPath("package-info.java");
     final File fileWithoutParent = new MockFile(path);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpSinglelineCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpSinglelineCheckTest.java
@@ -31,7 +31,7 @@ import java.io.File;
 import java.nio.charset.StandardCharsets;
 import org.junit.jupiter.api.Test;
 
-public class RegexpSinglelineCheckTest extends AbstractModuleTestSupport {
+final class RegexpSinglelineCheckTest extends AbstractModuleTestSupport {
 
   private static final String[] EMPTY = {};
 
@@ -41,7 +41,7 @@ public class RegexpSinglelineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIt() throws Exception {
+  void it() throws Exception {
     final String[] expected = {
       "77: " + getCheckMessage(MSG_REGEXP_EXCEEDED, "System\\.(out)|(err)\\.print(ln)?\\("),
     };
@@ -49,7 +49,7 @@ public class RegexpSinglelineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMessageProperty() throws Exception {
+  void messageProperty() throws Exception {
     final String[] expected = {
       "78: Bad line :(",
     };
@@ -57,7 +57,7 @@ public class RegexpSinglelineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreCaseTrue() throws Exception {
+  void ignoreCaseTrue() throws Exception {
 
     final String[] expected = {
       "78: " + getCheckMessage(MSG_REGEXP_EXCEEDED, "SYSTEM\\.(OUT)|(ERR)\\.PRINT(LN)?\\("),
@@ -66,13 +66,13 @@ public class RegexpSinglelineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreCaseFalse() throws Exception {
+  void ignoreCaseFalse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRegexpSinglelineSemantic4.java"), expected);
   }
 
   @Test
-  public void testMinimum() throws Exception {
+  void minimum() throws Exception {
     final String[] expected = {
       "1: " + getCheckMessage(MSG_REGEXP_MINIMUM, "500", "\\r"),
     };
@@ -81,7 +81,7 @@ public class RegexpSinglelineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSetMessage() throws Exception {
+  void setMessage() throws Exception {
     final String[] expected = {
       "1: someMessage",
     };
@@ -90,7 +90,7 @@ public class RegexpSinglelineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMaximum() throws Exception {
+  void maximum() throws Exception {
     verifyWithInlineConfigParser(getPath("InputRegexpSinglelineSemantic7.java"), EMPTY);
   }
 
@@ -100,7 +100,7 @@ public class RegexpSinglelineCheckTest extends AbstractModuleTestSupport {
    * @throws Exception some Exception
    */
   @Test
-  public void testStateIsBeingReset() throws Exception {
+  void stateIsBeingReset() throws Exception {
     final String illegal = "System\\.(out)|(err)\\.print(ln)?\\(";
     final TestLoggingReporter reporter = new TestLoggingReporter();
     final DetectorOptions detectorOptions =
@@ -117,12 +117,12 @@ public class RegexpSinglelineCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     verifyWithInlineConfigParser(getPath("InputRegexpSinglelineSemantic9.java"), EMPTY);
   }
 
   @Test
-  public void testMessage() throws Exception {
+  void message() throws Exception {
 
     final String[] expected = {
       "17: " + getCheckMessage(MSG_REGEXP_EXCEEDED, "SYSTEM\\.(OUT)|(ERR)\\.PRINT(LN)?\\("),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpSinglelineJavaCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpSinglelineJavaCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class RegexpSinglelineJavaCheckTest extends AbstractModuleTestSupport {
+final class RegexpSinglelineJavaCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class RegexpSinglelineJavaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final RegexpSinglelineJavaCheck regexpSinglelineJavaCheck = new RegexpSinglelineJavaCheck();
     assertWithMessage("Default acceptable tokens are invalid")
         .that(regexpSinglelineJavaCheck.getAcceptableTokens())
@@ -43,7 +43,7 @@ public class RegexpSinglelineJavaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final RegexpSinglelineJavaCheck checkObj = new RegexpSinglelineJavaCheck();
     assertWithMessage("Default required tokens are invalid")
         .that(checkObj.getRequiredTokens())
@@ -51,7 +51,7 @@ public class RegexpSinglelineJavaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIt() throws Exception {
+  void it() throws Exception {
     final String[] expected = {
       "77: " + getCheckMessage(MSG_REGEXP_EXCEEDED, "System\\.(out)|(err)\\.print(ln)?\\("),
     };
@@ -59,7 +59,7 @@ public class RegexpSinglelineJavaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMessageProperty() throws Exception {
+  void messageProperty() throws Exception {
     final String[] expected = {
       "78: " + "Bad line :(",
     };
@@ -67,7 +67,7 @@ public class RegexpSinglelineJavaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreCaseTrue() throws Exception {
+  void ignoreCaseTrue() throws Exception {
     final String[] expected = {
       "78: " + getCheckMessage(MSG_REGEXP_EXCEEDED, "SYSTEM\\.(OUT)|(ERR)\\.PRINT(LN)?\\("),
     };
@@ -75,13 +75,13 @@ public class RegexpSinglelineJavaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreCaseFalse() throws Exception {
+  void ignoreCaseFalse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRegexpSinglelineJavaSemantic4.java"), expected);
   }
 
   @Test
-  public void testIgnoreCommentsCppStyle() throws Exception {
+  void ignoreCommentsCppStyle() throws Exception {
     // See if the comment is removed properly
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
@@ -89,7 +89,7 @@ public class RegexpSinglelineJavaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreCommentsFalseCppStyle() throws Exception {
+  void ignoreCommentsFalseCppStyle() throws Exception {
     // See if the comment is removed properly
     final String[] expected = {
       "16: " + getCheckMessage(MSG_REGEXP_EXCEEDED, "don't\\suse trailing comments"),
@@ -99,7 +99,7 @@ public class RegexpSinglelineJavaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreCommentsBlockStyle() throws Exception {
+  void ignoreCommentsBlockStyle() throws Exception {
     // See if the comment is removed properly
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
@@ -107,7 +107,7 @@ public class RegexpSinglelineJavaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreCommentsFalseBlockStyle() throws Exception {
+  void ignoreCommentsFalseBlockStyle() throws Exception {
     final String[] expected = {
       "31: " + getCheckMessage(MSG_REGEXP_EXCEEDED, "c-style\\s1"),
     };
@@ -116,7 +116,7 @@ public class RegexpSinglelineJavaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreCommentsMultipleBlockStyle() throws Exception {
+  void ignoreCommentsMultipleBlockStyle() throws Exception {
     // See if a second comment on the same line is removed properly
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
@@ -124,21 +124,21 @@ public class RegexpSinglelineJavaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreCommentsMultiLine() throws Exception {
+  void ignoreCommentsMultiLine() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputRegexpSinglelineJavaTrailingComment6.java"), expected);
   }
 
   @Test
-  public void testIgnoreCommentsInlineStart() throws Exception {
+  void ignoreCommentsInlineStart() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputRegexpSinglelineJavaTrailingComment7.java"), expected);
   }
 
   @Test
-  public void testIgnoreCommentsInlineEnd() throws Exception {
+  void ignoreCommentsInlineEnd() throws Exception {
     final String[] expected = {
       "34: " + getCheckMessage(MSG_REGEXP_EXCEEDED, "int z"),
     };
@@ -147,7 +147,7 @@ public class RegexpSinglelineJavaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreCommentsInlineMiddle() throws Exception {
+  void ignoreCommentsInlineMiddle() throws Exception {
     final String[] expected = {
       "35: " + getCheckMessage(MSG_REGEXP_EXCEEDED, "int y"),
     };
@@ -156,7 +156,7 @@ public class RegexpSinglelineJavaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreCommentsNoSpaces() throws Exception {
+  void ignoreCommentsNoSpaces() throws Exception {
     // make sure the comment is not turned into spaces
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
@@ -164,7 +164,7 @@ public class RegexpSinglelineJavaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test1371588() throws Exception {
+  void test1371588() throws Exception {
     // StackOverflowError with trailing space and ignoreComments
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
@@ -172,19 +172,19 @@ public class RegexpSinglelineJavaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExistingInDoc() throws Exception {
+  void existingInDoc() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRegexpSinglelineJavaSemantic5.java"), expected);
   }
 
   @Test
-  public void testExistingInCode() throws Exception {
+  void existingInCode() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRegexpSinglelineJavaSemantic6.java"), expected);
   }
 
   @Test
-  public void testMissing() throws Exception {
+  void missing() throws Exception {
     final String[] expected = {
       "1: " + getCheckMessage(MSG_REGEXP_MINIMUM, 1, "This\\stext is not in the file"),
     };
@@ -192,7 +192,7 @@ public class RegexpSinglelineJavaCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputRegexpSinglelineJavaSemantic8.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/sizes/AnonInnerLengthCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/sizes/AnonInnerLengthCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
 /** Unit test for AnonInnerLengthCheck. */
-public class AnonInnerLengthCheckTest extends AbstractModuleTestSupport {
+final class AnonInnerLengthCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class AnonInnerLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final AnonInnerLengthCheck checkObj = new AnonInnerLengthCheck();
     final int[] expected = {TokenTypes.LITERAL_NEW};
     assertWithMessage("Default required tokens are invalid")
@@ -44,7 +44,7 @@ public class AnonInnerLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final AnonInnerLengthCheck anonInnerLengthCheckObj = new AnonInnerLengthCheck();
     final int[] actual = anonInnerLengthCheckObj.getAcceptableTokens();
     final int[] expected = {TokenTypes.LITERAL_NEW};
@@ -53,7 +53,7 @@ public class AnonInnerLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "53:35: " + getCheckMessage(MSG_KEY, 21, 20),
     };
@@ -61,7 +61,7 @@ public class AnonInnerLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonDefault() throws Exception {
+  void nonDefault() throws Exception {
     final String[] expected = {
       "54:35: " + getCheckMessage(MSG_KEY, 21, 6), "79:35: " + getCheckMessage(MSG_KEY, 20, 6),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/sizes/ExecutableStatementCountCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/sizes/ExecutableStatementCountCheckTest.java
@@ -32,16 +32,16 @@ import java.util.Collection;
 import org.antlr.v4.runtime.CommonToken;
 import org.junit.jupiter.api.Test;
 
-public class ExecutableStatementCountCheckTest extends AbstractModuleTestSupport {
+final class ExecutableStatementCountCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/sizes/executablestatementcount";
   }
 
-  @Test
   @SuppressWarnings("unchecked")
-  public void testStatefulFieldsClearedOnBeginTree() {
+  @Test
+  void statefulFieldsClearedOnBeginTree() {
     final DetailAstImpl ast = new DetailAstImpl();
     ast.setType(TokenTypes.STATIC_INIT);
     final ExecutableStatementCountCheck check = new ExecutableStatementCountCheck();
@@ -56,7 +56,7 @@ public class ExecutableStatementCountCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testMaxZero() throws Exception {
+  void maxZero() throws Exception {
 
     final String[] expected = {
       "12:5: " + getCheckMessage(MSG_KEY, 3, 0),
@@ -76,7 +76,7 @@ public class ExecutableStatementCountCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testMethodDef() throws Exception {
+  void methodDef() throws Exception {
 
     final String[] expected = {
       "12:5: " + getCheckMessage(MSG_KEY, 3, 0),
@@ -91,7 +91,7 @@ public class ExecutableStatementCountCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testCtorDef() throws Exception {
+  void ctorDef() throws Exception {
 
     final String[] expected = {
       "12:5: " + getCheckMessage(MSG_KEY, 2, 0), "22:5: " + getCheckMessage(MSG_KEY, 2, 0),
@@ -101,7 +101,7 @@ public class ExecutableStatementCountCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testStaticInit() throws Exception {
+  void staticInit() throws Exception {
 
     final String[] expected = {
       "13:5: " + getCheckMessage(MSG_KEY, 2, 0),
@@ -111,7 +111,7 @@ public class ExecutableStatementCountCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testInstanceInit() throws Exception {
+  void instanceInit() throws Exception {
 
     final String[] expected = {
       "13:5: " + getCheckMessage(MSG_KEY, 2, 0),
@@ -122,7 +122,7 @@ public class ExecutableStatementCountCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testVisitTokenWithWrongTokenType() {
+  void visitTokenWithWrongTokenType() {
     final ExecutableStatementCountCheck checkObj = new ExecutableStatementCountCheck();
     final DetailAstImpl ast = new DetailAstImpl();
     ast.initialize(new CommonToken(TokenTypes.ENUM, "ENUM"));
@@ -135,7 +135,7 @@ public class ExecutableStatementCountCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testLeaveTokenWithWrongTokenType() {
+  void leaveTokenWithWrongTokenType() {
     final ExecutableStatementCountCheck checkObj = new ExecutableStatementCountCheck();
     final DetailAstImpl ast = new DetailAstImpl();
     ast.initialize(new CommonToken(TokenTypes.ENUM, "ENUM"));
@@ -148,7 +148,7 @@ public class ExecutableStatementCountCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testDefaultConfiguration() throws Exception {
+  void defaultConfiguration() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
@@ -156,7 +156,7 @@ public class ExecutableStatementCountCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testExecutableStatementCountRecords() throws Exception {
+  void executableStatementCountRecords() throws Exception {
 
     final int max = 1;
 
@@ -174,7 +174,7 @@ public class ExecutableStatementCountCheckTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testExecutableStatementCountLambdas() throws Exception {
+  void executableStatementCountLambdas() throws Exception {
 
     final int max = 1;
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/sizes/FileLengthCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/sizes/FileLengthCheckTest.java
@@ -28,7 +28,7 @@ import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class FileLengthCheckTest extends AbstractModuleTestSupport {
+final class FileLengthCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -36,7 +36,7 @@ public class FileLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAlarm() throws Exception {
+  void alarm() throws Exception {
     final String[] expected = {
       "1: " + getCheckMessage(MSG_KEY, 228, 20),
     };
@@ -44,25 +44,25 @@ public class FileLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAlarmDefault() throws Exception {
+  void alarmDefault() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputFileLengthDefault.java"), expected);
   }
 
   @Test
-  public void testFileLengthEqualToMaxLength() throws Exception {
+  void fileLengthEqualToMaxLength() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputFileLength2.java"), expected);
   }
 
   @Test
-  public void testOk() throws Exception {
+  void ok() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputFileLength3.java"), expected);
   }
 
   @Test
-  public void testArgs() throws Exception {
+  void args() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(FileLengthCheck.class);
     try {
       checkConfig.addProperty("max", "abc");
@@ -79,14 +79,14 @@ public class FileLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoAlarmByExtension() throws Exception {
+  void noAlarmByExtension() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputFileLength4.java"), expected);
   }
 
   @Test
-  public void testExtensions() {
+  void extensions() {
     final FileLengthCheck check = new FileLengthCheck();
     check.setFileExtensions("java");
     assertWithMessage("extension should be the same")
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/sizes/LambdaBodyLengthCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/sizes/LambdaBodyLengthCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class LambdaBodyLengthCheckTest extends AbstractModuleTestSupport {
+final class LambdaBodyLengthCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class LambdaBodyLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final LambdaBodyLengthCheck checkObj = new LambdaBodyLengthCheck();
     final int[] expected = {TokenTypes.LAMBDA};
     assertWithMessage("Default required tokens are invalid")
@@ -44,7 +44,7 @@ public class LambdaBodyLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final LambdaBodyLengthCheck lambdaBodyLengthCheckObj = new LambdaBodyLengthCheck();
     final int[] actual = lambdaBodyLengthCheckObj.getAcceptableTokens();
     final int[] expected = {TokenTypes.LAMBDA};
@@ -53,7 +53,7 @@ public class LambdaBodyLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "16:27: " + getCheckMessage(MSG_KEY, 12, 10),
       "28:27: " + getCheckMessage(MSG_KEY, 12, 10),
@@ -66,14 +66,14 @@ public class LambdaBodyLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultSwitchExpressions() throws Exception {
+  void defaultSwitchExpressions() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getNonCompilablePath("InputLambdaBodyLengthSwitchExps.java"), expected);
   }
 
   @Test
-  public void testMaxLimitIsDifferent() throws Exception {
+  void maxLimitIsDifferent() throws Exception {
     final String[] expected = {
       "16:27: " + getCheckMessage(MSG_KEY, 4, 3),
       "20:27: " + getCheckMessage(MSG_KEY, 4, 3),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/sizes/LineLengthCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/sizes/LineLengthCheckTest.java
@@ -27,7 +27,7 @@ import de.thetaphi.forbiddenapis.SuppressForbidden;
 import java.nio.charset.CodingErrorAction;
 import org.junit.jupiter.api.Test;
 
-public class LineLengthCheckTest extends AbstractModuleTestSupport {
+final class LineLengthCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class LineLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSimple() throws Exception {
+  void simple() throws Exception {
     final String[] expected = {
       "22: " + getCheckMessage(MSG_KEY, 80, 81), "149: " + getCheckMessage(MSG_KEY, 80, 83),
     };
@@ -43,7 +43,7 @@ public class LineLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void shouldLogActualLineLength() throws Exception {
+  void shouldLogActualLineLength() throws Exception {
     final String[] expected = {
       "23: 80,81", "150: 80,83",
     };
@@ -51,7 +51,7 @@ public class LineLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void shouldNotLogLongImportStatements() throws Exception {
+  void shouldNotLogLongImportStatements() throws Exception {
     final String[] expected = {
       "18: " + getCheckMessage(MSG_KEY, 80, 100),
     };
@@ -59,7 +59,7 @@ public class LineLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void shouldNotLogLongPackageStatements() throws Exception {
+  void shouldNotLogLongPackageStatements() throws Exception {
     final String[] expected = {
       "17: " + getCheckMessage(MSG_KEY, 80, 100),
     };
@@ -68,7 +68,7 @@ public class LineLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void shouldNotLogLongLinks() throws Exception {
+  void shouldNotLogLongLinks() throws Exception {
     final String[] expected = {
       "13: " + getCheckMessage(MSG_KEY, 80, 111),
     };
@@ -76,7 +76,7 @@ public class LineLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void countUnicodePointsOnce() throws Exception {
+  void countUnicodePointsOnce() throws Exception {
     final String[] expected = {
       "15: " + getCheckMessage(MSG_KEY, 100, 149), "16: " + getCheckMessage(MSG_KEY, 100, 149),
     };
@@ -84,7 +84,7 @@ public class LineLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLineLengthIgnoringPackageStatements() throws Exception {
+  void lineLengthIgnoringPackageStatements() throws Exception {
     final String[] expected = {
       "13: " + getCheckMessage(MSG_KEY, 75, 76),
       "22: " + getCheckMessage(MSG_KEY, 75, 86),
@@ -97,7 +97,7 @@ public class LineLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLineLengthIgnoringImportStatements() throws Exception {
+  void lineLengthIgnoringImportStatements() throws Exception {
     final String[] expected = {
       "12: " + getCheckMessage(MSG_KEY, 75, 79),
       "21: " + getCheckMessage(MSG_KEY, 75, 81),
@@ -119,7 +119,7 @@ public class LineLengthCheckTest extends AbstractModuleTestSupport {
    */
   @SuppressForbidden
   @Test
-  public void testUnmappableCharacters() throws Exception {
+  void unmappableCharacters() throws Exception {
     final String[] expected = {
       "4: " + getCheckMessage(MSG_KEY, 75, 238),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/sizes/MethodCountCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/sizes/MethodCountCheckTest.java
@@ -31,7 +31,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class MethodCountCheckTest extends AbstractModuleTestSupport {
+final class MethodCountCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -39,7 +39,7 @@ public class MethodCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final MethodCountCheck checkObj = new MethodCountCheck();
     final int[] expected = {TokenTypes.METHOD_DEF};
     assertWithMessage("Default required tokens are invalid")
@@ -48,7 +48,7 @@ public class MethodCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final MethodCountCheck methodCountCheckObj = new MethodCountCheck();
     final int[] actual = methodCountCheckObj.getAcceptableTokens();
     final int[] expected = {
@@ -65,7 +65,7 @@ public class MethodCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaults() throws Exception {
+  void defaults() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -73,7 +73,7 @@ public class MethodCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testThreesOne() throws Exception {
+  void threesOne() throws Exception {
 
     final String[] expected = {
       "15:1: " + getCheckMessage(MSG_PACKAGE_METHODS, 4, 3),
@@ -87,7 +87,7 @@ public class MethodCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testThreesTwo() throws Exception {
+  void threesTwo() throws Exception {
 
     final String[] expected = {
       "14:1: " + getCheckMessage(MSG_PACKAGE_METHODS, 4, 3),
@@ -103,7 +103,7 @@ public class MethodCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEnum() throws Exception {
+  void testEnum() throws Exception {
 
     final String[] expected = {
       "21:5: " + getCheckMessage(MSG_PRIVATE_METHODS, 1, 0),
@@ -114,7 +114,7 @@ public class MethodCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithPackageModifier() throws Exception {
+  void withPackageModifier() throws Exception {
 
     final String[] expected = {
       "15:1: " + getCheckMessage(MSG_MANY_METHODS, 5, 2),
@@ -124,7 +124,7 @@ public class MethodCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOnInterfaceDefinitionWithField() throws Exception {
+  void onInterfaceDefinitionWithField() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -132,7 +132,7 @@ public class MethodCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithInterfaceDefinitionInClass() throws Exception {
+  void withInterfaceDefinitionInClass() throws Exception {
 
     final String[] expected = {
       "15:1: " + getCheckMessage(MSG_MANY_METHODS, 2, 1),
@@ -142,7 +142,7 @@ public class MethodCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPartialTokens() throws Exception {
+  void partialTokens() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -150,7 +150,7 @@ public class MethodCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCountMethodToCorrectDefinition() throws Exception {
+  void countMethodToCorrectDefinition() throws Exception {
 
     final String[] expected = {
       "22:5: " + getCheckMessage(MSG_MANY_METHODS, 2, 1),
@@ -160,7 +160,7 @@ public class MethodCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInterfaceMemberScopeIsPublic() throws Exception {
+  void interfaceMemberScopeIsPublic() throws Exception {
 
     final String[] expected = {
       "17:5: " + getCheckMessage(MSG_PUBLIC_METHODS, 2, 1),
@@ -172,7 +172,7 @@ public class MethodCountCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMethodCountRecords() throws Exception {
+  void methodCountRecords() throws Exception {
     final int max = 2;
 
     final String[] expected = {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/sizes/MethodLengthCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/sizes/MethodLengthCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class MethodLengthCheckTest extends AbstractModuleTestSupport {
+final class MethodLengthCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class MethodLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final MethodLengthCheck checkObj = new MethodLengthCheck();
     assertWithMessage(
             "MethodLengthCheck#getRequiredTokens should return empty array " + "by default")
@@ -44,7 +44,7 @@ public class MethodLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final MethodLengthCheck methodLengthCheckObj = new MethodLengthCheck();
     final int[] actual = methodLengthCheckObj.getAcceptableTokens();
     final int[] expected = {
@@ -55,13 +55,13 @@ public class MethodLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testItOne() throws Exception {
+  void itOne() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMethodLengthSimpleOne.java"), expected);
   }
 
   @Test
-  public void testItTwo() throws Exception {
+  void itTwo() throws Exception {
     final String[] expected = {
       "16:5: " + getCheckMessage(MSG_KEY, 20, 19, "longMethod"),
     };
@@ -69,13 +69,13 @@ public class MethodLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCountEmptyIsFalse() throws Exception {
+  void countEmptyIsFalse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMethodLengthCountEmptyIsFalse.java"), expected);
   }
 
   @Test
-  public void testWithComments() throws Exception {
+  void withComments() throws Exception {
     final String[] expected = {
       "34:5: " + getCheckMessage(MSG_KEY, 8, 7, "visit"),
     };
@@ -83,7 +83,7 @@ public class MethodLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCountEmpty() throws Exception {
+  void countEmpty() throws Exception {
     final int max = 2;
     final String[] expected = {
       "24:5: " + getCheckMessage(MSG_KEY, 3, max, "AA"),
@@ -96,19 +96,19 @@ public class MethodLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAbstractOne() throws Exception {
+  void abstractOne() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMethodLengthModifierOne.java"), expected);
   }
 
   @Test
-  public void testAbstractTwo() throws Exception {
+  void abstractTwo() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMethodLengthModifierTwo.java"), expected);
   }
 
   @Test
-  public void testTextBlocks() throws Exception {
+  void textBlocks() throws Exception {
     final int max = 2;
 
     final String[] expected = {
@@ -123,7 +123,7 @@ public class MethodLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRecordsAndCompactCtors() throws Exception {
+  void recordsAndCompactCtors() throws Exception {
 
     final int max = 2;
 
@@ -140,7 +140,7 @@ public class MethodLengthCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRecordsAndCompactCtorsCountEmpty() throws Exception {
+  void recordsAndCompactCtorsCountEmpty() throws Exception {
     final int max = 2;
 
     final String[] expected = {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/sizes/OuterTypeNumberCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/sizes/OuterTypeNumberCheckTest.java
@@ -32,7 +32,7 @@ import java.io.File;
 import java.util.Optional;
 import org.junit.jupiter.api.Test;
 
-public class OuterTypeNumberCheckTest extends AbstractModuleTestSupport {
+final class OuterTypeNumberCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -40,7 +40,7 @@ public class OuterTypeNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final OuterTypeNumberCheck checkObj = new OuterTypeNumberCheck();
     final int[] expected = {
       TokenTypes.CLASS_DEF,
@@ -55,7 +55,7 @@ public class OuterTypeNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final OuterTypeNumberCheck outerTypeNumberObj = new OuterTypeNumberCheck();
     final int[] actual = outerTypeNumberObj.getAcceptableTokens();
     final int[] expected = {
@@ -70,7 +70,7 @@ public class OuterTypeNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "8:1: " + getCheckMessage(MSG_KEY, 3, 1),
     };
@@ -78,19 +78,19 @@ public class OuterTypeNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMax30() throws Exception {
+  void max30() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputOuterTypeNumberSimple1.java"), expected);
   }
 
   @Test
-  public void testWithInnerClass() throws Exception {
+  void withInnerClass() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputOuterTypeNumberEmptyInner.java"), expected);
   }
 
   @Test
-  public void testWithRecords() throws Exception {
+  void withRecords() throws Exception {
 
     final int max = 1;
 
@@ -109,7 +109,7 @@ public class OuterTypeNumberCheckTest extends AbstractModuleTestSupport {
    * @throws Exception if there is an error.
    */
   @Test
-  public void testClearState() throws Exception {
+  void clearState() throws Exception {
     final OuterTypeNumberCheck check = new OuterTypeNumberCheck();
     final DetailAST root =
         JavaParser.parseFile(
@@ -123,14 +123,17 @@ public class OuterTypeNumberCheckTest extends AbstractModuleTestSupport {
         .that(
             TestUtil.isStatefulFieldClearedDuringBeginTree(
                 check,
-                classDef.get(),
+                classDef.orElseThrow(),
                 "currentDepth",
                 currentDepth -> ((Number) currentDepth).intValue() == 0))
         .isTrue();
     assertWithMessage("State is not cleared on beginTree")
         .that(
             TestUtil.isStatefulFieldClearedDuringBeginTree(
-                check, classDef.get(), "outerNum", outerNum -> ((Number) outerNum).intValue() == 0))
+                check,
+                classDef.orElseThrow(),
+                "outerNum",
+                outerNum -> ((Number) outerNum).intValue() == 0))
         .isTrue();
   }
 }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/sizes/ParameterNumberCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/sizes/ParameterNumberCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class ParameterNumberCheckTest extends AbstractModuleTestSupport {
+final class ParameterNumberCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class ParameterNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final ParameterNumberCheck checkObj = new ParameterNumberCheck();
     assertWithMessage(
             "ParameterNumberCheck#getRequiredTokens should return empty array " + "by default")
@@ -44,7 +44,7 @@ public class ParameterNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final ParameterNumberCheck paramNumberCheckObj = new ParameterNumberCheck();
     final int[] actual = paramNumberCheckObj.getAcceptableTokens();
     final int[] expected = {
@@ -55,7 +55,7 @@ public class ParameterNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "198:10: " + getCheckMessage(MSG_KEY, 7, 9),
     };
@@ -63,7 +63,7 @@ public class ParameterNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNum() throws Exception {
+  void num() throws Exception {
     final String[] expected = {
       "75:9: " + getCheckMessage(MSG_KEY, 2, 3), "198:10: " + getCheckMessage(MSG_KEY, 2, 9),
     };
@@ -71,13 +71,13 @@ public class ParameterNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMaxParam() throws Exception {
+  void maxParam() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputParameterNumberSimple3.java"), expected);
   }
 
   @Test
-  public void shouldLogActualParameterNumber() throws Exception {
+  void shouldLogActualParameterNumber() throws Exception {
     final String[] expected = {
       "199:10: 7,9",
     };
@@ -85,7 +85,7 @@ public class ParameterNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreOverriddenMethods() throws Exception {
+  void ignoreOverriddenMethods() throws Exception {
     final String[] expected = {
       "15:10: " + getCheckMessage(MSG_KEY, 7, 8), "20:10: " + getCheckMessage(MSG_KEY, 7, 8),
     };
@@ -93,7 +93,7 @@ public class ParameterNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreOverriddenMethodsFalse() throws Exception {
+  void ignoreOverriddenMethodsFalse() throws Exception {
     final String[] expected = {
       "15:10: " + getCheckMessage(MSG_KEY, 7, 8),
       "20:10: " + getCheckMessage(MSG_KEY, 7, 8),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/sizes/RecordComponentNumberCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/sizes/RecordComponentNumberCheckTest.java
@@ -29,7 +29,7 @@ import com.puppycrawl.tools.checkstyle.internal.utils.TestUtil;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class RecordComponentNumberCheckTest extends AbstractModuleTestSupport {
+final class RecordComponentNumberCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -37,7 +37,7 @@ public class RecordComponentNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final RecordComponentNumberCheck checkObj = new RecordComponentNumberCheck();
     final int[] actual = checkObj.getRequiredTokens();
     final int[] expected = {
@@ -48,7 +48,7 @@ public class RecordComponentNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final RecordComponentNumberCheck checkObj = new RecordComponentNumberCheck();
     final int[] actual = checkObj.getAcceptableTokens();
     final int[] expected = {
@@ -59,7 +59,7 @@ public class RecordComponentNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
 
     final int max = 8;
 
@@ -77,7 +77,7 @@ public class RecordComponentNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRecordComponentNumberTopLevel1() throws Exception {
+  void recordComponentNumberTopLevel1() throws Exception {
 
     final int max = 8;
 
@@ -90,7 +90,7 @@ public class RecordComponentNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRecordComponentNumberTopLevel2() throws Exception {
+  void recordComponentNumberTopLevel2() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -99,7 +99,7 @@ public class RecordComponentNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRecordComponentNumberMax1() throws Exception {
+  void recordComponentNumberMax1() throws Exception {
 
     final int max = 1;
 
@@ -125,7 +125,7 @@ public class RecordComponentNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRecordComponentNumberMax20() throws Exception {
+  void recordComponentNumberMax20() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(
@@ -133,7 +133,7 @@ public class RecordComponentNumberCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRecordComponentNumberPrivateModifier() throws Exception {
+  void recordComponentNumberPrivateModifier() throws Exception {
 
     final int max = 8;
 
@@ -155,7 +155,7 @@ public class RecordComponentNumberCheckTest extends AbstractModuleTestSupport {
    * @throws Exception if an error occurs.
    */
   @Test
-  public void testCloneInAccessModifiersProperty() throws Exception {
+  void cloneInAccessModifiersProperty() throws Exception {
     final AccessModifierOption[] input = {
       AccessModifierOption.PACKAGE,
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/EmptyForInitializerPadCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/EmptyForInitializerPadCheckTest.java
@@ -30,7 +30,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class EmptyForInitializerPadCheckTest extends AbstractModuleTestSupport {
+final class EmptyForInitializerPadCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -38,7 +38,7 @@ public class EmptyForInitializerPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final EmptyForInitializerPadCheck checkObj = new EmptyForInitializerPadCheck();
     final int[] expected = {TokenTypes.FOR_INIT};
     assertWithMessage("Default required tokens are invalid")
@@ -47,7 +47,7 @@ public class EmptyForInitializerPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "51:15: " + getCheckMessage(MSG_PRECEDED, ";"),
     };
@@ -56,7 +56,7 @@ public class EmptyForInitializerPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSpaceOption() throws Exception {
+  void spaceOption() throws Exception {
     final String[] expected = {
       "54:14: " + getCheckMessage(MSG_NOT_PRECEDED, ";"),
     };
@@ -64,7 +64,7 @@ public class EmptyForInitializerPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final EmptyForInitializerPadCheck emptyForInitializerPadCheckObj =
         new EmptyForInitializerPadCheck();
     final int[] actual = emptyForInitializerPadCheckObj.getAcceptableTokens();
@@ -79,7 +79,7 @@ public class EmptyForInitializerPadCheckTest extends AbstractModuleTestSupport {
    * valueOf() is uncovered.
    */
   @Test
-  public void testPadOptionValueOf() {
+  void padOptionValueOf() {
     final PadOption option = PadOption.valueOf("NOSPACE");
     assertWithMessage("Result of valueOf is invalid").that(option).isEqualTo(PadOption.NOSPACE);
   }
@@ -89,13 +89,13 @@ public class EmptyForInitializerPadCheckTest extends AbstractModuleTestSupport {
    * valueOf() is uncovered.
    */
   @Test
-  public void testWrapOptionValueOf() {
+  void wrapOptionValueOf() {
     final WrapOption option = WrapOption.valueOf("EOL");
     assertWithMessage("Result of valueOf is invalid").that(option).isEqualTo(WrapOption.EOL);
   }
 
   @Test
-  public void testWithEmoji() throws Exception {
+  void withEmoji() throws Exception {
     final String[] expected = {
       "23:13: " + getCheckMessage(MSG_NOT_PRECEDED, ";"),
       "28:25: " + getCheckMessage(MSG_NOT_PRECEDED, ";"),
@@ -104,7 +104,7 @@ public class EmptyForInitializerPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidOption() throws Exception {
+  void invalidOption() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(EmptyForInitializerPadCheck.class);
     checkConfig.addProperty("option", "invalid_option");
 
@@ -125,7 +125,7 @@ public class EmptyForInitializerPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTrimOptionProperty() throws Exception {
+  void trimOptionProperty() throws Exception {
     final String[] expected = {
       "15:14: " + getCheckMessage(MSG_NOT_PRECEDED, ";"),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/EmptyForIteratorPadCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/EmptyForIteratorPadCheckTest.java
@@ -29,7 +29,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class EmptyForIteratorPadCheckTest extends AbstractModuleTestSupport {
+final class EmptyForIteratorPadCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -37,7 +37,7 @@ public class EmptyForIteratorPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final EmptyForIteratorPadCheck checkObj = new EmptyForIteratorPadCheck();
     final int[] expected = {TokenTypes.FOR_ITERATOR};
     assertWithMessage("Default required tokens are invalid")
@@ -46,7 +46,7 @@ public class EmptyForIteratorPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "30:32: " + getCheckMessage(MSG_WS_FOLLOWED, ";"),
       "46:33: " + getCheckMessage(MSG_WS_FOLLOWED, ";"),
@@ -56,7 +56,7 @@ public class EmptyForIteratorPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSpaceOption() throws Exception {
+  void spaceOption() throws Exception {
     final String[] expected = {
       "26:31: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, ";"),
     };
@@ -64,7 +64,7 @@ public class EmptyForIteratorPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithEmoji() throws Exception {
+  void withEmoji() throws Exception {
     final String[] expected = {
       "24:40: " + getCheckMessage(MSG_WS_FOLLOWED, ";"),
     };
@@ -72,7 +72,7 @@ public class EmptyForIteratorPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final EmptyForIteratorPadCheck emptyForIteratorPadCheckObj = new EmptyForIteratorPadCheck();
     final int[] actual = emptyForIteratorPadCheckObj.getAcceptableTokens();
     final int[] expected = {
@@ -82,7 +82,7 @@ public class EmptyForIteratorPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidOption() throws Exception {
+  void invalidOption() throws Exception {
     try {
       final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -100,7 +100,7 @@ public class EmptyForIteratorPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTrimOptionProperty() throws Exception {
+  void trimOptionProperty() throws Exception {
     final String[] expected = {
       "20:31: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, ";"),
     };
@@ -109,7 +109,7 @@ public class EmptyForIteratorPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUppercaseOptionProperty() throws Exception {
+  void uppercaseOptionProperty() throws Exception {
     final String[] expected = {
       "20:31: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, ";"),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/EmptyLineSeparatorCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/EmptyLineSeparatorCheckTest.java
@@ -31,7 +31,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
+final class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -39,7 +39,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final EmptyLineSeparatorCheck checkObj = new EmptyLineSeparatorCheck();
     assertWithMessage(
             "EmptyLineSeparatorCheck#getRequiredTokens should return empty array " + "by default")
@@ -48,7 +48,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
 
     final String[] expected = {
       "14:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "import"),
@@ -65,7 +65,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowNoEmptyLineBetweenFields() throws Exception {
+  void allowNoEmptyLineBetweenFields() throws Exception {
 
     final String[] expected = {
       "14:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "import"),
@@ -81,7 +81,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testHeader() throws Exception {
+  void header() throws Exception {
     final String[] expected = {
       "12:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "package"),
     };
@@ -89,7 +89,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMultipleEmptyLinesBetweenClassMembers() throws Exception {
+  void multipleEmptyLinesBetweenClassMembers() throws Exception {
     final String[] expected = {
       "14:1: " + getCheckMessage(MSG_MULTIPLE_LINES, "package"),
       "17:1: " + getCheckMessage(MSG_MULTIPLE_LINES, "import"),
@@ -104,20 +104,20 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFormerArrayIndexOutOfBounds() throws Exception {
+  void formerArrayIndexOutOfBounds() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputEmptyLineSeparatorFormerException.java"), expected);
   }
 
   @Test
-  public void testAllowMultipleFieldInClass() throws Exception {
+  void allowMultipleFieldInClass() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputEmptyLineSeparatorMultipleFieldsInClass.java"), expected);
   }
 
   @Test
-  public void testAllowMultipleImportSeparatedFromPackage() throws Exception {
+  void allowMultipleImportSeparatedFromPackage() throws Exception {
     final String[] expected = {
       "13:78: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "import"),
     };
@@ -126,14 +126,14 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testImportSeparatedFromPackage() throws Exception {
+  void importSeparatedFromPackage() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputEmptyLineSeparatorImportSeparatedFromPackage.java"), expected);
   }
 
   @Test
-  public void testStaticImport() throws Exception {
+  void staticImport() throws Exception {
     final String[] expected = {
       "17:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "CLASS_DEF"),
     };
@@ -141,7 +141,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBlockCommentNotSeparatedFromPackage() throws Exception {
+  void blockCommentNotSeparatedFromPackage() throws Exception {
     final String[] expected = {
       "14:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "/*"),
     };
@@ -150,7 +150,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSingleCommentNotSeparatedFromPackage() throws Exception {
+  void singleCommentNotSeparatedFromPackage() throws Exception {
     final String[] expected = {
       "14:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "//"),
     };
@@ -159,7 +159,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClassDefinitionNotSeparatedFromPackage() throws Exception {
+  void classDefinitionNotSeparatedFromPackage() throws Exception {
     final String[] expected = {
       "14:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "CLASS_DEF"),
     };
@@ -168,7 +168,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommentAfterPackageWithImports() throws Exception {
+  void commentAfterPackageWithImports() throws Exception {
     final String[] expected = {
       "14:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "//"),
     };
@@ -177,7 +177,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadocCommentAfterPackageWithImports() throws Exception {
+  void javadocCommentAfterPackageWithImports() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(EmptyLineSeparatorCheck.class);
     final String[] expected = {
       "2:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "/*"),
@@ -187,7 +187,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackageImportsClassInSingleLine() throws Exception {
+  void packageImportsClassInSingleLine() throws Exception {
     final String[] expected = {
       "13:79: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "import"),
       "13:101: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "CLASS_DEF"),
@@ -197,7 +197,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyLineAfterPackageForPackageAst() throws Exception {
+  void emptyLineAfterPackageForPackageAst() throws Exception {
     final String[] expected = {
       "12:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "/*"),
     };
@@ -206,14 +206,14 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyLineAfterPackageForImportAst() throws Exception {
+  void emptyLineAfterPackageForImportAst() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputEmptyLineSeparatorEmptyLineAfterPackageForImportAst.java"), expected);
   }
 
   @Test
-  public void testClassDefinitionAndCommentNotSeparatedFromPackage() throws Exception {
+  void classDefinitionAndCommentNotSeparatedFromPackage() throws Exception {
     final String[] expected = {
       "14:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "//"),
       "15:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "CLASS_DEF"),
@@ -224,21 +224,21 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBlockCommentSeparatedFromPackage() throws Exception {
+  void blockCommentSeparatedFromPackage() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputEmptyLineSeparatorBlockCommentSeparatedFromPackage.java"), expected);
   }
 
   @Test
-  public void testSingleCommentSeparatedFromPackage() throws Exception {
+  void singleCommentSeparatedFromPackage() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputEmptyLineSeparatorSingleCommentSeparatedFromPackage.java"), expected);
   }
 
   @Test
-  public void testEnumMembers() throws Exception {
+  void enumMembers() throws Exception {
     final String[] expected = {
       "22:5: " + getCheckMessage(MSG_MULTIPLE_LINES, "VARIABLE_DEF"),
       "27:5: " + getCheckMessage(MSG_MULTIPLE_LINES, "VARIABLE_DEF"),
@@ -251,7 +251,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInterfaceFields() throws Exception {
+  void interfaceFields() throws Exception {
     final String[] expected = {
       "21:5: " + getCheckMessage(MSG_MULTIPLE_LINES, "VARIABLE_DEF"),
       "25:5: " + getCheckMessage(MSG_MULTIPLE_LINES, "VARIABLE_DEF"),
@@ -263,7 +263,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final EmptyLineSeparatorCheck emptyLineSeparatorCheckObj = new EmptyLineSeparatorCheck();
     final int[] actual = emptyLineSeparatorCheckObj.getAcceptableTokens();
     final int[] expected = {
@@ -285,7 +285,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPrePreviousLineEmptiness() throws Exception {
+  void prePreviousLineEmptiness() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(EmptyLineSeparatorCheck.class);
     checkConfig.addProperty("allowMultipleEmptyLines", "false");
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -293,7 +293,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPrePreviousLineIsEmpty() throws Exception {
+  void prePreviousLineIsEmpty() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(EmptyLineSeparatorCheck.class);
     checkConfig.addProperty("allowMultipleEmptyLines", "false");
     final String[] expected = {
@@ -303,7 +303,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPreviousLineEmptiness() throws Exception {
+  void previousLineEmptiness() throws Exception {
     final String[] expected = {
       "21:30: " + getCheckMessage(MSG_MULTIPLE_LINES_INSIDE),
       "26:5: " + getCheckMessage(MSG_MULTIPLE_LINES_INSIDE),
@@ -316,7 +316,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDisAllowMultipleEmptyLinesInsideClassMembers() throws Exception {
+  void disAllowMultipleEmptyLinesInsideClassMembers() throws Exception {
     final String[] expected = {
       "18:11: " + getCheckMessage(MSG_MULTIPLE_LINES_INSIDE),
       "30:11: " + getCheckMessage(MSG_MULTIPLE_LINES_INSIDE),
@@ -330,7 +330,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowMultipleEmptyLinesInsideClassMembers() throws Exception {
+  void allowMultipleEmptyLinesInsideClassMembers() throws Exception {
     final String[] expected = {
       "53:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "CLASS_DEF"),
     };
@@ -339,25 +339,25 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testImportsAndStaticImports() throws Exception {
+  void importsAndStaticImports() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputEmptyLineSeparatorImports.java"), expected);
   }
 
   @Test
-  public void testAllowPackageAnnotation() throws Exception {
+  void allowPackageAnnotation() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("packageinfo/test1/package-info.java"), expected);
   }
 
   @Test
-  public void testAllowJavadocBeforePackage() throws Exception {
+  void allowJavadocBeforePackage() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("packageinfo/test2/package-info.java"), expected);
   }
 
   @Test
-  public void testDisAllowBlockCommentBeforePackage() throws Exception {
+  void disAllowBlockCommentBeforePackage() throws Exception {
     final String[] expected = {
       "15:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "package"),
     };
@@ -365,7 +365,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowSingleLineCommentPackage() throws Exception {
+  void allowSingleLineCommentPackage() throws Exception {
     final String[] expected = {
       "16:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "package"),
     };
@@ -373,7 +373,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonPackageInfoWithJavadocBeforePackage() throws Exception {
+  void nonPackageInfoWithJavadocBeforePackage() throws Exception {
     final String[] expected = {
       "15:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "package"),
     };
@@ -382,7 +382,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClassOnly() throws Exception {
+  void classOnly() throws Exception {
     final String[] expected = {
       "51:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "CLASS_DEF"),
     };
@@ -391,7 +391,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLineSeparationBeforeComments() throws Exception {
+  void lineSeparationBeforeComments() throws Exception {
     final String[] expected = {
       "12:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "package"),
       "16:1: " + getCheckMessage(MSG_MULTIPLE_LINES, "//"),
@@ -436,7 +436,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreEmptyLinesBeforeCommentsWhenItIsAllowed() throws Exception {
+  void ignoreEmptyLinesBeforeCommentsWhenItIsAllowed() throws Exception {
     final String[] expected = {
       "12:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "package"),
       "239:5: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "INTERFACE_DEF"),
@@ -445,14 +445,14 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoViolationsOnEmptyLinesBeforeComments() throws Exception {
+  void noViolationsOnEmptyLinesBeforeComments() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputEmptyLineSeparatorNoViolationOnEmptyLineBeforeComments.java"), expected);
   }
 
   @Test
-  public void testEmptyLineSeparatorRecordsAndCompactCtors() throws Exception {
+  void emptyLineSeparatorRecordsAndCompactCtors() throws Exception {
     final String[] expected = {
       "14:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "package"),
       "18:5: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "RECORD_DEF"),
@@ -476,7 +476,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyLineSeparatorRecordsAndCompactCtorsNoEmptyLines() throws Exception {
+  void emptyLineSeparatorRecordsAndCompactCtorsNoEmptyLines() throws Exception {
 
     final String[] expected = {
       "14:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "package"),
@@ -490,7 +490,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyLineSeparatorMultipleSingleTypeVariables() throws Exception {
+  void emptyLineSeparatorMultipleSingleTypeVariables() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -499,7 +499,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyLineSeparatorEmptyLinesInsideClassMembersRecursive() throws Exception {
+  void emptyLineSeparatorEmptyLinesInsideClassMembersRecursive() throws Exception {
     final String[] expected = {
       "27:15: " + getCheckMessage(MSG_MULTIPLE_LINES_INSIDE),
     };
@@ -507,7 +507,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyLineSeparatorNewMethodDef() throws Exception {
+  void emptyLineSeparatorNewMethodDef() throws Exception {
     final String[] expected = {
       "29:34: " + getCheckMessage(MSG_MULTIPLE_LINES_INSIDE),
       "38:26: " + getCheckMessage(MSG_MULTIPLE_LINES_INSIDE),
@@ -516,7 +516,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyLineSeparatorPostFixCornerCases() throws Exception {
+  void emptyLineSeparatorPostFixCornerCases() throws Exception {
     final String[] expected = {
       "18:19: " + getCheckMessage(MSG_MULTIPLE_LINES_INSIDE),
       "32:29: " + getCheckMessage(MSG_MULTIPLE_LINES_INSIDE),
@@ -527,7 +527,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyLineSeparatorAnnotation() throws Exception {
+  void emptyLineSeparatorAnnotation() throws Exception {
     final String[] expected = {
       "18:22: " + getCheckMessage(MSG_MULTIPLE_LINES_AFTER, "}"),
     };
@@ -535,7 +535,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyLineSeparatorWithEmoji() throws Exception {
+  void emptyLineSeparatorWithEmoji() throws Exception {
 
     final String[] expected = {
       "22:5: " + getCheckMessage(MSG_MULTIPLE_LINES, "VARIABLE_DEF"),
@@ -547,13 +547,13 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMultipleLines() throws Exception {
+  void multipleLines() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputEmptyLineSeparatorMultipleLines.java"), expected);
   }
 
   @Test
-  public void testMultipleLines2() throws Exception {
+  void multipleLines2() throws Exception {
     final String[] expected = {
       "15:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "CLASS_DEF"),
     };
@@ -561,7 +561,7 @@ public class EmptyLineSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMultipleLines3() throws Exception {
+  void multipleLines3() throws Exception {
     final String[] expected = {
       "24:5: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "VARIABLE_DEF"),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/FileTabCharacterCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/FileTabCharacterCheckTest.java
@@ -25,7 +25,7 @@ import static com.puppycrawl.tools.checkstyle.checks.whitespace.FileTabCharacter
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class FileTabCharacterCheckTest extends AbstractModuleTestSupport {
+final class FileTabCharacterCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class FileTabCharacterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "22:25: " + getCheckMessage(MSG_FILE_CONTAINS_TAB),
     };
@@ -41,7 +41,7 @@ public class FileTabCharacterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCustomMessage() throws Exception {
+  void customMessage() throws Exception {
     final String msgFileContainsTab =
         "File contains tab characters (this is the first instance) :)";
     final String[] expected = {
@@ -51,7 +51,7 @@ public class FileTabCharacterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testVerbose() throws Exception {
+  void verbose() throws Exception {
     final String[] expected = {
       "22:25: " + getCheckMessage(MSG_CONTAINS_TAB),
       "148:35: " + getCheckMessage(MSG_CONTAINS_TAB),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/GenericWhitespaceCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/GenericWhitespaceCheckTest.java
@@ -40,7 +40,7 @@ import java.util.Optional;
 import org.antlr.v4.runtime.CommonToken;
 import org.junit.jupiter.api.Test;
 
-public class GenericWhitespaceCheckTest extends AbstractModuleTestSupport {
+final class GenericWhitespaceCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -48,7 +48,7 @@ public class GenericWhitespaceCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final GenericWhitespaceCheck checkObj = new GenericWhitespaceCheck();
     final int[] expected = {
       TokenTypes.GENERIC_START, TokenTypes.GENERIC_END,
@@ -59,7 +59,7 @@ public class GenericWhitespaceCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "22:14: " + getCheckMessage(MSG_WS_PRECEDED, "<"),
       "22:14: " + getCheckMessage(MSG_WS_FOLLOWED, "<"),
@@ -100,7 +100,7 @@ public class GenericWhitespaceCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAtTheStartOfTheLine() throws Exception {
+  void atTheStartOfTheLine() throws Exception {
     final String[] expected = {
       "16:2: " + getCheckMessage(MSG_WS_PRECEDED, ">"),
       "18:2: " + getCheckMessage(MSG_WS_PRECEDED, "<"),
@@ -109,7 +109,7 @@ public class GenericWhitespaceCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNestedGeneric() throws Exception {
+  void nestedGeneric() throws Exception {
     final String[] expected = {
       "17:1: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "&"),
     };
@@ -117,25 +117,25 @@ public class GenericWhitespaceCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testList() throws Exception {
+  void list() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputGenericWhitespaceList.java"), expected);
   }
 
   @Test
-  public void testInnerClass() throws Exception {
+  void innerClass() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputGenericWhitespaceInnerClass.java"), expected);
   }
 
   @Test
-  public void testMethodReferences() throws Exception {
+  void methodReferences() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputGenericWhitespaceMethodRef1.java"), expected);
   }
 
   @Test
-  public void testMethodReferences2() throws Exception {
+  void methodReferences2() throws Exception {
     final String[] expected = {
       "16:37: " + getCheckMessage(MSG_WS_FOLLOWED, ">"),
     };
@@ -143,13 +143,13 @@ public class GenericWhitespaceCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGenericEndsTheLine() throws Exception {
+  void genericEndsTheLine() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputGenericWhitespaceEndsTheLine.java"), expected);
   }
 
   @Test
-  public void testGenericWhitespaceWithEmoji() throws Exception {
+  void genericWhitespaceWithEmoji() throws Exception {
     final String[] expected = {
       "35:2: " + getCheckMessage(MSG_WS_PRECEDED, '>'),
       "40:35: " + getCheckMessage(MSG_WS_PRECEDED, '<'),
@@ -167,7 +167,7 @@ public class GenericWhitespaceCheckTest extends AbstractModuleTestSupport {
    * @throws Exception if there is an error.
    */
   @Test
-  public void testClearState() throws Exception {
+  void clearState() throws Exception {
     final GenericWhitespaceCheck check = new GenericWhitespaceCheck();
     final FileText fileText =
         new FileText(
@@ -181,12 +181,15 @@ public class GenericWhitespaceCheckTest extends AbstractModuleTestSupport {
     assertWithMessage("State is not cleared on beginTree")
         .that(
             TestUtil.isStatefulFieldClearedDuringBeginTree(
-                check, genericStart.get(), "depth", depth -> ((Number) depth).intValue() == 0))
+                check,
+                genericStart.orElseThrow(),
+                "depth",
+                depth -> ((Number) depth).intValue() == 0))
         .isTrue();
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final GenericWhitespaceCheck genericWhitespaceCheckObj = new GenericWhitespaceCheck();
     final int[] actual = genericWhitespaceCheckObj.getAcceptableTokens();
     final int[] expected = {
@@ -196,7 +199,7 @@ public class GenericWhitespaceCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWrongTokenType() {
+  void wrongTokenType() {
     final GenericWhitespaceCheck genericWhitespaceCheckObj = new GenericWhitespaceCheck();
     final DetailAstImpl ast = new DetailAstImpl();
     ast.initialize(new CommonToken(TokenTypes.INTERFACE_DEF, "interface"));
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/MethodParamPadCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/MethodParamPadCheckTest.java
@@ -30,7 +30,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class MethodParamPadCheckTest extends AbstractModuleTestSupport {
+final class MethodParamPadCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -38,7 +38,7 @@ public class MethodParamPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final MethodParamPadCheck checkObj = new MethodParamPadCheck();
     assertWithMessage(
             "MethodParamPadCheck#getRequiredTokens should return empty array " + "by default")
@@ -47,7 +47,7 @@ public class MethodParamPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "21:32: " + getCheckMessage(MSG_WS_PRECEDED, "("),
       "23:15: " + getCheckMessage(MSG_WS_PRECEDED, "("),
@@ -72,7 +72,7 @@ public class MethodParamPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowLineBreaks() throws Exception {
+  void allowLineBreaks() throws Exception {
     final String[] expected = {
       "21:33: " + getCheckMessage(MSG_WS_PRECEDED, "("),
       "23:15: " + getCheckMessage(MSG_WS_PRECEDED, "("),
@@ -88,7 +88,7 @@ public class MethodParamPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSpaceOption() throws Exception {
+  void spaceOption() throws Exception {
     final String[] expected = {
       "16:32: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "("),
       "18:14: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "("),
@@ -117,7 +117,7 @@ public class MethodParamPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMethodParamPadRecords() throws Exception {
+  void methodParamPadRecords() throws Exception {
     final String[] expected = {
       "19:16: " + getCheckMessage(MSG_WS_PRECEDED, "("),
       "20:34: " + getCheckMessage(MSG_WS_PRECEDED, "("),
@@ -134,13 +134,13 @@ public class MethodParamPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test1322879() throws Exception {
+  void test1322879() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMethodParamPadWhitespaceAround.java"), expected);
   }
 
   @Test
-  public void testMethodParamPadCheckWithEmoji() throws Exception {
+  void methodParamPadCheckWithEmoji() throws Exception {
     final String[] expected = {
       "19:31: " + getCheckMessage(MSG_WS_PRECEDED, "("),
       "21:30: " + getCheckMessage(MSG_WS_PRECEDED, "("),
@@ -156,7 +156,7 @@ public class MethodParamPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final MethodParamPadCheck methodParamPadCheckObj = new MethodParamPadCheck();
     final int[] actual = methodParamPadCheckObj.getAcceptableTokens();
     final int[] expected = {
@@ -172,7 +172,7 @@ public class MethodParamPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidOption() throws Exception {
+  void invalidOption() throws Exception {
     try {
       final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -190,7 +190,7 @@ public class MethodParamPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTrimOptionProperty() throws Exception {
+  void trimOptionProperty() throws Exception {
     final String[] expected = {
       "15:24: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "("),
       "26:27: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "("),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/NoLineWrapCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/NoLineWrapCheckTest.java
@@ -25,7 +25,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class NoLineWrapCheckTest extends AbstractModuleTestSupport {
+final class NoLineWrapCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,13 +33,13 @@ public class NoLineWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCaseWithoutLineWrapping() throws Exception {
+  void caseWithoutLineWrapping() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputNoLineWrapGood.java"), expected);
   }
 
   @Test
-  public void testDefaultTokensLineWrapping() throws Exception {
+  void defaultTokensLineWrapping() throws Exception {
     final String[] expected = {
       "8:1: " + getCheckMessage(MSG_KEY, "package"),
       "13:1: " + getCheckMessage(MSG_KEY, "import"),
@@ -49,7 +49,7 @@ public class NoLineWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCustomTokensLineWrapping() throws Exception {
+  void customTokensLineWrapping() throws Exception {
     final String[] expected = {
       "13:1: " + getCheckMessage(MSG_KEY, "import"),
       "17:1: " + getCheckMessage(MSG_KEY, "import"),
@@ -61,7 +61,7 @@ public class NoLineWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoLineWrapRecordsAndCompactCtors() throws Exception {
+  void noLineWrapRecordsAndCompactCtors() throws Exception {
 
     final String[] expected = {
       "13:9: " + getCheckMessage(MSG_KEY, "CTOR_DEF"),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/NoWhitespaceAfterCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/NoWhitespaceAfterCheckTest.java
@@ -29,7 +29,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.antlr.v4.runtime.CommonToken;
 import org.junit.jupiter.api.Test;
 
-public class NoWhitespaceAfterCheckTest extends AbstractModuleTestSupport {
+final class NoWhitespaceAfterCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -37,7 +37,7 @@ public class NoWhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "10:13: " + getCheckMessage(MSG_KEY, "."),
       "11:11: " + getCheckMessage(MSG_KEY, "."),
@@ -61,13 +61,13 @@ public class NoWhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAssignment() throws Exception {
+  void assignment() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputNoWhitespaceAfterTestAssignment.java"), expected);
   }
 
   @Test
-  public void testDotAllowLineBreaks() throws Exception {
+  void dotAllowLineBreaks() throws Exception {
     final String[] expected = {
       "9:13: " + getCheckMessage(MSG_KEY, "."),
       "129:23: " + getCheckMessage(MSG_KEY, "."),
@@ -78,7 +78,7 @@ public class NoWhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTypecast() throws Exception {
+  void typecast() throws Exception {
     final String[] expected = {
       "87:20: " + getCheckMessage(MSG_KEY, ")"),
       "89:13: " + getCheckMessage(MSG_KEY, ")"),
@@ -88,7 +88,7 @@ public class NoWhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testArrayDeclarations() throws Exception {
+  void arrayDeclarations() throws Exception {
     final String[] expected = {
       "14:12: " + getCheckMessage(MSG_KEY, "Object"),
       "16:23: " + getCheckMessage(MSG_KEY, "someStuff3"),
@@ -116,7 +116,7 @@ public class NoWhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testArrayDeclarations2() throws Exception {
+  void arrayDeclarations2() throws Exception {
     final String[] expected = {
       "20:31: " + getCheckMessage(MSG_KEY, "]"),
       "25:41: " + getCheckMessage(MSG_KEY, "create"),
@@ -166,12 +166,12 @@ public class NoWhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testArrayDeclarations3() throws Exception {
+  void arrayDeclarations3() throws Exception {
     verifyWithInlineConfigParser(getPath("InputNoWhitespaceAfterArrayDeclarations3.java"));
   }
 
   @Test
-  public void testSynchronized() throws Exception {
+  void testSynchronized() throws Exception {
     final String[] expected = {
       "22:9: " + getCheckMessage(MSG_KEY, "synchronized"),
     };
@@ -179,12 +179,12 @@ public class NoWhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNpe() throws Exception {
+  void npe() throws Exception {
     verifyWithInlineConfigParser(getPath("InputNoWhitespaceAfterTestNpe.java"));
   }
 
   @Test
-  public void testMethodReference() throws Exception {
+  void methodReference() throws Exception {
     final String[] expected = {
       "17:41: " + getCheckMessage(MSG_KEY, "int"), "18:62: " + getCheckMessage(MSG_KEY, "String"),
     };
@@ -192,7 +192,7 @@ public class NoWhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMethodReferenceAfter() throws Exception {
+  void methodReferenceAfter() throws Exception {
     final String[] expected = {
       "25:35: " + getCheckMessage(MSG_KEY, "::"), "26:64: " + getCheckMessage(MSG_KEY, "::"),
     };
@@ -201,7 +201,7 @@ public class NoWhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testArrayDeclarator() throws Exception {
+  void arrayDeclarator() throws Exception {
     final String[] expected = {
       "19:32: " + getCheckMessage(MSG_KEY, "Entry"),
     };
@@ -210,7 +210,7 @@ public class NoWhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testVisitTokenSwitchReflection() {
+  void visitTokenSwitchReflection() {
     // unexpected parent for ARRAY_DECLARATOR token
     final DetailAstImpl astImport = mockAST(TokenTypes.IMPORT, "import");
     final DetailAstImpl astArrayDeclarator = mockAST(TokenTypes.ARRAY_DECLARATOR, "[");
@@ -230,7 +230,7 @@ public class NoWhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllTokens() throws Exception {
+  void allTokens() throws Exception {
     final String[] expected = {
       "10:13: " + getCheckMessage(MSG_KEY, "."),
       "11:11: " + getCheckMessage(MSG_KEY, "."),
@@ -259,14 +259,14 @@ public class NoWhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testArrayDeclarationsAndAnnotations() throws Exception {
+  void arrayDeclarationsAndAnnotations() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputNoWhitespaceAfterArrayDeclarationsAndAnno.java"), expected);
   }
 
   @Test
-  public void testArrayNewTypeStructure() throws Exception {
+  void arrayNewTypeStructure() throws Exception {
     final String[] expected = {
       "53:17: " + getCheckMessage(MSG_KEY, "ci"),
       "54:27: " + getCheckMessage(MSG_KEY, "int"),
@@ -297,7 +297,7 @@ public class NoWhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testArrayNewGenericTypeArgument() throws Exception {
+  void arrayNewGenericTypeArgument() throws Exception {
 
     final String[] expected = {
       "59:15: " + getCheckMessage(MSG_KEY, "i"),
@@ -323,7 +323,7 @@ public class NoWhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoWhitespaceAfterWithEmoji() throws Exception {
+  void noWhitespaceAfterWithEmoji() throws Exception {
 
     final String[] expected = {
       "16:16: " + getCheckMessage(MSG_KEY, "String"),
@@ -339,7 +339,7 @@ public class NoWhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoWhitespaceAfterSynchronized() throws Exception {
+  void noWhitespaceAfterSynchronized() throws Exception {
     final String[] expected = {
       "18:9: " + getCheckMessage(MSG_KEY, "synchronized"),
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/NoWhitespaceBeforeCaseDefaultColonCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/NoWhitespaceBeforeCaseDefaultColonCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class NoWhitespaceBeforeCaseDefaultColonCheckTest extends AbstractModuleTestSupport {
+final class NoWhitespaceBeforeCaseDefaultColonCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class NoWhitespaceBeforeCaseDefaultColonCheckTest extends AbstractModuleT
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     createModuleConfig(NoWhitespaceBeforeCaseDefaultColonCheck.class);
     final String[] expected = {
       "15:20: " + getCheckMessage(MSG_KEY, ":"),
@@ -56,7 +56,7 @@ public class NoWhitespaceBeforeCaseDefaultColonCheckTest extends AbstractModuleT
   }
 
   @Test
-  public void testDefaultNonCompilable() throws Exception {
+  void defaultNonCompilable() throws Exception {
     createModuleConfig(NoWhitespaceBeforeCaseDefaultColonCheck.class);
     final String[] expected = {
       "36:22: " + getCheckMessage(MSG_KEY, ":"),
@@ -74,7 +74,7 @@ public class NoWhitespaceBeforeCaseDefaultColonCheckTest extends AbstractModuleT
   }
 
   @Test
-  public void testAcceptableTokenIsColon() {
+  void acceptableTokenIsColon() {
     final NoWhitespaceBeforeCaseDefaultColonCheck check =
         new NoWhitespaceBeforeCaseDefaultColonCheck();
     assertWithMessage("Acceptable token should be colon")
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/NoWhitespaceBeforeCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/NoWhitespaceBeforeCheckTest.java
@@ -25,7 +25,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class NoWhitespaceBeforeCheckTest extends AbstractModuleTestSupport {
+final class NoWhitespaceBeforeCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class NoWhitespaceBeforeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "34:15: " + getCheckMessage(MSG_KEY, "++"),
       "34:22: " + getCheckMessage(MSG_KEY, "--"),
@@ -53,7 +53,7 @@ public class NoWhitespaceBeforeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDot() throws Exception {
+  void dot() throws Exception {
     final String[] expected = {
       "9:13: " + getCheckMessage(MSG_KEY, "."),
       "10:5: " + getCheckMessage(MSG_KEY, "."),
@@ -66,7 +66,7 @@ public class NoWhitespaceBeforeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDotAllowLineBreaks() throws Exception {
+  void dotAllowLineBreaks() throws Exception {
     final String[] expected = {
       "9:13: " + getCheckMessage(MSG_KEY, "."),
       "133:18: " + getCheckMessage(MSG_KEY, "."),
@@ -77,7 +77,7 @@ public class NoWhitespaceBeforeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMethodReference() throws Exception {
+  void methodReference() throws Exception {
     final String[] expected = {
       "25:32: " + getCheckMessage(MSG_KEY, "::"), "26:61: " + getCheckMessage(MSG_KEY, "::"),
     };
@@ -85,7 +85,7 @@ public class NoWhitespaceBeforeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDotAtTheStartOfTheLine() throws Exception {
+  void dotAtTheStartOfTheLine() throws Exception {
     final String[] expected = {
       "10:1: " + getCheckMessage(MSG_KEY, "."),
     };
@@ -93,7 +93,7 @@ public class NoWhitespaceBeforeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMethodRefAtTheStartOfTheLine() throws Exception {
+  void methodRefAtTheStartOfTheLine() throws Exception {
     final String[] expected = {
       "22:3: " + getCheckMessage(MSG_KEY, "::"),
     };
@@ -102,7 +102,7 @@ public class NoWhitespaceBeforeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyForLoop() throws Exception {
+  void emptyForLoop() throws Exception {
     final String[] expected = {
       "20:24: " + getCheckMessage(MSG_KEY, ";"), "26:32: " + getCheckMessage(MSG_KEY, ";"),
     };
@@ -110,7 +110,7 @@ public class NoWhitespaceBeforeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoWhitespaceBeforeTextBlocksWithTabIndent() throws Exception {
+  void noWhitespaceBeforeTextBlocksWithTabIndent() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -119,7 +119,7 @@ public class NoWhitespaceBeforeCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoWhitespaceBeforeWithEmoji() throws Exception {
+  void noWhitespaceBeforeWithEmoji() throws Exception {
     final String[] expected = {
       "13:15: " + getCheckMessage(MSG_KEY, ","),
       "14:17: " + getCheckMessage(MSG_KEY, ","),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/OperatorWrapCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/OperatorWrapCheckTest.java
@@ -28,7 +28,7 @@ import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class OperatorWrapCheckTest extends AbstractModuleTestSupport {
+final class OperatorWrapCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -36,7 +36,7 @@ public class OperatorWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "23:19: " + getCheckMessage(MSG_LINE_NEW, "+"),
       "24:15: " + getCheckMessage(MSG_LINE_NEW, "-"),
@@ -48,7 +48,7 @@ public class OperatorWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOpWrapEol() throws Exception {
+  void opWrapEol() throws Exception {
     final String[] expected = {
       "26:13: " + getCheckMessage(MSG_LINE_PREVIOUS, "-"),
       "30:13: " + getCheckMessage(MSG_LINE_PREVIOUS, "&&"),
@@ -58,7 +58,7 @@ public class OperatorWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonDefOpsDefault() throws Exception {
+  void nonDefOpsDefault() throws Exception {
     final String[] expected = {
       "37:33: " + getCheckMessage(MSG_LINE_NEW, "::"),
     };
@@ -66,7 +66,7 @@ public class OperatorWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonDefOpsWrapEol() throws Exception {
+  void nonDefOpsWrapEol() throws Exception {
     final String[] expected = {
       "35:21: " + getCheckMessage(MSG_LINE_PREVIOUS, "::"),
       "40:21: " + getCheckMessage(MSG_LINE_PREVIOUS, "::"),
@@ -75,7 +75,7 @@ public class OperatorWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAssignEol() throws Exception {
+  void assignEol() throws Exception {
     final String[] expected = {
       "46:13: " + getCheckMessage(MSG_LINE_PREVIOUS, "="),
     };
@@ -83,7 +83,7 @@ public class OperatorWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEol() throws Exception {
+  void eol() throws Exception {
     final String[] expected = {
       "21:17: " + getCheckMessage(MSG_LINE_PREVIOUS, "="),
       "22:17: " + getCheckMessage(MSG_LINE_PREVIOUS, "*"),
@@ -99,7 +99,7 @@ public class OperatorWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNl() throws Exception {
+  void nl() throws Exception {
     final String[] expected = {
       "20:16: " + getCheckMessage(MSG_LINE_NEW, "="),
       "21:19: " + getCheckMessage(MSG_LINE_NEW, "*"),
@@ -114,7 +114,7 @@ public class OperatorWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testArraysAssign() throws Exception {
+  void arraysAssign() throws Exception {
     final String[] expected = {
       "18:22: " + getCheckMessage(MSG_LINE_NEW, "="),
       "36:28: " + getCheckMessage(MSG_LINE_NEW, "="),
@@ -124,7 +124,7 @@ public class OperatorWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGuardedPattern() throws Exception {
+  void guardedPattern() throws Exception {
     final String[] expected = {
       "52:30: " + getCheckMessage(MSG_LINE_NEW, "&&"),
       "54:31: " + getCheckMessage(MSG_LINE_NEW, "&&"),
@@ -142,13 +142,13 @@ public class OperatorWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTryWithResources() throws Exception {
+  void tryWithResources() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputOperatorWrapTryWithResources.java"), expected);
   }
 
   @Test
-  public void testInvalidOption() throws Exception {
+  void invalidOption() throws Exception {
 
     try {
       final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -167,7 +167,7 @@ public class OperatorWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTrimOptionProperty() throws Exception {
+  void trimOptionProperty() throws Exception {
     final String[] expected = {
       "18:21: " + getCheckMessage(MSG_LINE_PREVIOUS, ":"),
       "19:21: " + getCheckMessage(MSG_LINE_PREVIOUS, "?"),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/ParenPadCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/ParenPadCheckTest.java
@@ -33,7 +33,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
 import org.junit.jupiter.api.Test;
 
-public class ParenPadCheckTest extends AbstractModuleTestSupport {
+final class ParenPadCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -41,7 +41,7 @@ public class ParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "65:11: " + getCheckMessage(MSG_WS_FOLLOWED, "("),
       "65:37: " + getCheckMessage(MSG_WS_PRECEDED, ")"),
@@ -57,7 +57,7 @@ public class ParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSpace() throws Exception {
+  void space() throws Exception {
     final String[] expected = {
       "36:19: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "("),
       "36:23: " + getCheckMessage(MSG_WS_NOT_PRECEDED, ")"),
@@ -99,7 +99,7 @@ public class ParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultForIterator() throws Exception {
+  void defaultForIterator() throws Exception {
     final String[] expected = {
       "24:35: " + getCheckMessage(MSG_WS_PRECEDED, ")"),
       "27:36: " + getCheckMessage(MSG_WS_PRECEDED, ")"),
@@ -113,7 +113,7 @@ public class ParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSpaceEmptyForIterator() throws Exception {
+  void spaceEmptyForIterator() throws Exception {
     final String[] expected = {
       "18:13: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "("),
       "18:35: " + getCheckMessage(MSG_WS_NOT_PRECEDED, ")"),
@@ -129,20 +129,20 @@ public class ParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test1322879() throws Exception {
+  void test1322879() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputParenPadWithSpace.java"), expected);
   }
 
   @Test
-  public void testTrimOptionProperty() throws Exception {
+  void trimOptionProperty() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getPath("InputParenPadToCheckTrimFunctionInOptionProperty.java"), expected);
   }
 
   @Test
-  public void testNospaceWithComplexInput() throws Exception {
+  void nospaceWithComplexInput() throws Exception {
     final String[] expected = {
       "55:26: " + getCheckMessage(MSG_WS_FOLLOWED, "("),
       "55:28: " + getCheckMessage(MSG_WS_PRECEDED, ")"),
@@ -270,7 +270,7 @@ public class ParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testConfigureTokens() throws Exception {
+  void configureTokens() throws Exception {
     final String[] expected = {
       "98:39: " + getCheckMessage(MSG_WS_PRECEDED, ")"),
       "121:22: " + getCheckMessage(MSG_WS_FOLLOWED, "("),
@@ -303,7 +303,7 @@ public class ParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidOption() throws Exception {
+  void invalidOption() throws Exception {
 
     try {
       final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -322,7 +322,7 @@ public class ParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLambdaAssignment() throws Exception {
+  void lambdaAssignment() throws Exception {
     final String[] expected = {
       "20:41: " + getCheckMessage(MSG_WS_FOLLOWED, "("),
       "20:45: " + getCheckMessage(MSG_WS_PRECEDED, ")"),
@@ -341,7 +341,7 @@ public class ParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLambdaAssignmentWithSpace() throws Exception {
+  void lambdaAssignmentWithSpace() throws Exception {
     final String[] expected = {
       "20:41: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "("),
       "20:43: " + getCheckMessage(MSG_WS_NOT_PRECEDED, ")"),
@@ -358,7 +358,7 @@ public class ParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLambdaCheckDisabled() throws Exception {
+  void lambdaCheckDisabled() throws Exception {
     final String[] expected = {
       "27:61: " + getCheckMessage(MSG_WS_FOLLOWED, "("),
       "27:63: " + getCheckMessage(MSG_WS_PRECEDED, ")"),
@@ -369,7 +369,7 @@ public class ParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLambdaCheckDisabledWithSpace() throws Exception {
+  void lambdaCheckDisabledWithSpace() throws Exception {
     final String[] expected = {
       "30:20: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "("),
       "30:33: " + getCheckMessage(MSG_WS_NOT_PRECEDED, ")"),
@@ -378,7 +378,7 @@ public class ParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLambdaCheckOnly() throws Exception {
+  void lambdaCheckOnly() throws Exception {
     final String[] expected = {
       "17:41: " + getCheckMessage(MSG_WS_FOLLOWED, "("),
       "17:45: " + getCheckMessage(MSG_WS_PRECEDED, ")"),
@@ -393,7 +393,7 @@ public class ParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLambdaCheckOnlyWithSpace() throws Exception {
+  void lambdaCheckOnlyWithSpace() throws Exception {
     final String[] expected = {
       "17:41: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "("),
       "17:43: " + getCheckMessage(MSG_WS_NOT_PRECEDED, ")"),
@@ -408,7 +408,7 @@ public class ParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLambdaCheckOnlyWithSpace1() throws Exception {
+  void lambdaCheckOnlyWithSpace1() throws Exception {
     final String[] expected = {
       "16:2: " + getCheckMessage(MSG_WS_NOT_PRECEDED, ")"),
     };
@@ -416,7 +416,7 @@ public class ParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTryWithResources() throws Exception {
+  void tryWithResources() throws Exception {
     final String[] expected = {
       "20:37: " + getCheckMessage(MSG_WS_PRECEDED, ")"),
       "21:61: " + getCheckMessage(MSG_WS_PRECEDED, ")"),
@@ -426,7 +426,7 @@ public class ParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTryWithResourcesAndSuppression() throws Exception {
+  void tryWithResourcesAndSuppression() throws Exception {
     final String[] expectedFiltered = CommonUtil.EMPTY_STRING_ARRAY;
     final String[] expectedUnfiltered = {
       "23:13: " + getCheckMessage(MSG_WS_FOLLOWED, "("),
@@ -438,13 +438,13 @@ public class ParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoStackoverflowError() throws Exception {
+  void noStackoverflowError() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithLimitedResources(getPath("InputParenPadNoStackoverflowError.java"), expected);
   }
 
   @Test
-  public void testParenPadCheckRecords() throws Exception {
+  void parenPadCheckRecords() throws Exception {
 
     final String[] expected = {
       "20:21: " + getCheckMessage(MSG_WS_FOLLOWED, "("),
@@ -465,7 +465,7 @@ public class ParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testParenPadCheckRecordsWithSpace() throws Exception {
+  void parenPadCheckRecordsWithSpace() throws Exception {
 
     final String[] expected = {
       "25:19: " + getCheckMessage(MSG_WS_NOT_PRECEDED, ")"),
@@ -486,7 +486,7 @@ public class ParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testParenPadCheckEmoji() throws Exception {
+  void parenPadCheckEmoji() throws Exception {
 
     final String[] expected = {
       "25:45: " + getCheckMessage(MSG_WS_PRECEDED, ")"),
@@ -500,7 +500,7 @@ public class ParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testParenPadForSynchronized() throws Exception {
+  void parenPadForSynchronized() throws Exception {
 
     final String[] expected = {
       "18:29: " + getCheckMessage(MSG_WS_PRECEDED, ")"),
@@ -509,7 +509,7 @@ public class ParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testParenPadForEnum() throws Exception {
+  void parenPadForEnum() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputParenPadForEnum.java"), expected);
@@ -524,7 +524,7 @@ public class ParenPadCheckTest extends AbstractModuleTestSupport {
    * pass that check.
    */
   @Test
-  public void testIsAcceptableToken() throws Exception {
+  void isAcceptableToken() throws Exception {
     final ParenPadCheck check = new ParenPadCheck();
     final DetailAstImpl ast = new DetailAstImpl();
     final String message =
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/SeparatorWrapCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/SeparatorWrapCheckTest.java
@@ -29,7 +29,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class SeparatorWrapCheckTest extends AbstractModuleTestSupport {
+final class SeparatorWrapCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -37,7 +37,7 @@ public class SeparatorWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDot() throws Exception {
+  void dot() throws Exception {
     final String[] expected = {
       "39:10: " + getCheckMessage(MSG_LINE_NEW, "."),
     };
@@ -45,7 +45,7 @@ public class SeparatorWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testComma() throws Exception {
+  void comma() throws Exception {
     final String[] expected = {
       "47:17: " + getCheckMessage(MSG_LINE_PREVIOUS, ","),
     };
@@ -53,7 +53,7 @@ public class SeparatorWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMethodRef() throws Exception {
+  void methodRef() throws Exception {
     final String[] expected = {
       "25:56: " + getCheckMessage(MSG_LINE_NEW, "::"),
     };
@@ -61,7 +61,7 @@ public class SeparatorWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetDefaultTokens() {
+  void getDefaultTokens() {
     final SeparatorWrapCheck separatorWrapCheckObj = new SeparatorWrapCheck();
     final int[] actual = separatorWrapCheckObj.getDefaultTokens();
     final int[] expected = {
@@ -71,7 +71,7 @@ public class SeparatorWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidOption() throws Exception {
+  void invalidOption() throws Exception {
 
     try {
       final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
@@ -90,7 +90,7 @@ public class SeparatorWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEllipsis() throws Exception {
+  void ellipsis() throws Exception {
     final String[] expected = {
       "19:13: " + getCheckMessage(MSG_LINE_PREVIOUS, "..."),
     };
@@ -98,7 +98,7 @@ public class SeparatorWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testArrayDeclarator() throws Exception {
+  void arrayDeclarator() throws Exception {
     final String[] expected = {
       "17:13: " + getCheckMessage(MSG_LINE_PREVIOUS, "["),
     };
@@ -106,7 +106,7 @@ public class SeparatorWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWithEmoji() throws Exception {
+  void withEmoji() throws Exception {
     final String[] expected = {
       "13:39: " + getCheckMessage(MSG_LINE_NEW, '['),
       "16:57: " + getCheckMessage(MSG_LINE_NEW, '['),
@@ -119,7 +119,7 @@ public class SeparatorWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTrimOptionProperty() throws Exception {
+  void trimOptionProperty() throws Exception {
     final String[] expected = {
       "18:44: " + getCheckMessage(MSG_LINE_NEW, "::"),
     };
@@ -127,7 +127,7 @@ public class SeparatorWrapCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCommaOnNewLine() throws Exception {
+  void commaOnNewLine() throws Exception {
     final String[] expected = {
       "16:10: " + getCheckMessage(MSG_LINE_NEW, ","),
       "21:26: " + getCheckMessage(MSG_LINE_NEW, ","),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/SingleSpaceSeparatorCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/SingleSpaceSeparatorCheckTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class SingleSpaceSeparatorCheckTest extends AbstractModuleTestSupport {
+final class SingleSpaceSeparatorCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,20 +34,20 @@ public class SingleSpaceSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoSpaceErrors() throws Exception {
+  void noSpaceErrors() throws Exception {
     verifyWithInlineConfigParser(
         getPath("InputSingleSpaceSeparatorNoErrors.java"), CommonUtil.EMPTY_STRING_ARRAY);
   }
 
   @Test
-  public void testNoStackoverflowError() throws Exception {
+  void noStackoverflowError() throws Exception {
     verifyWithLimitedResources(
         getPath("InputSingleSpaceSeparatorNoStackoverflowError.java"),
         CommonUtil.EMPTY_STRING_ARRAY);
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final SingleSpaceSeparatorCheck check = new SingleSpaceSeparatorCheck();
 
     assertWithMessage("Invalid acceptable tokens")
@@ -56,7 +56,7 @@ public class SingleSpaceSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSpaceErrors() throws Exception {
+  void spaceErrors() throws Exception {
     final String[] expected = {
       "8:10: " + getCheckMessage(MSG_KEY),
       "8:28: " + getCheckMessage(MSG_KEY),
@@ -96,7 +96,7 @@ public class SingleSpaceSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSpaceErrorsAroundComments() throws Exception {
+  void spaceErrorsAroundComments() throws Exception {
     final String[] expected = {
       "12:11: " + getCheckMessage(MSG_KEY),
       "12:43: " + getCheckMessage(MSG_KEY),
@@ -110,7 +110,7 @@ public class SingleSpaceSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSpaceErrorsInChildNodes() throws Exception {
+  void spaceErrorsInChildNodes() throws Exception {
     final String[] expected = {
       "12:16: " + getCheckMessage(MSG_KEY),
     };
@@ -119,7 +119,7 @@ public class SingleSpaceSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMinColumnNo() throws Exception {
+  void minColumnNo() throws Exception {
     final String[] expected = {
       "12:4: " + getCheckMessage(MSG_KEY),
     };
@@ -128,7 +128,7 @@ public class SingleSpaceSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWhitespaceInStartOfTheLine() throws Exception {
+  void whitespaceInStartOfTheLine() throws Exception {
     final String[] expected = {
       "12:7: " + getCheckMessage(MSG_KEY),
     };
@@ -137,7 +137,7 @@ public class SingleSpaceSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSpaceErrorsIfCommentsIgnored() throws Exception {
+  void spaceErrorsIfCommentsIgnored() throws Exception {
     final String[] expected = {
       "20:14: " + getCheckMessage(MSG_KEY),
     };
@@ -146,14 +146,14 @@ public class SingleSpaceSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmpty() throws Exception {
+  void empty() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("InputSingleSpaceSeparatorEmpty.java"), expected);
   }
 
   @Test
-  public void testSpaceErrorsWithEmoji() throws Exception {
+  void spaceErrorsWithEmoji() throws Exception {
     final String[] expected = {
       "14:18: " + getCheckMessage(MSG_KEY),
       "16:17: " + getCheckMessage(MSG_KEY),
@@ -173,7 +173,7 @@ public class SingleSpaceSeparatorCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSpaceErrorsAroundCommentsWithEmoji() throws Exception {
+  void spaceErrorsAroundCommentsWithEmoji() throws Exception {
     final String[] expected = {
       "25:22: " + getCheckMessage(MSG_KEY),
       "25:26: " + getCheckMessage(MSG_KEY),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/TypecastParenPadCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/TypecastParenPadCheckTest.java
@@ -30,7 +30,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class TypecastParenPadCheckTest extends AbstractModuleTestSupport {
+final class TypecastParenPadCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -38,7 +38,7 @@ public class TypecastParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "86:13: " + getCheckMessage(MSG_WS_FOLLOWED, "("),
       "86:22: " + getCheckMessage(MSG_WS_PRECEDED, ")"),
@@ -47,7 +47,7 @@ public class TypecastParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSpace() throws Exception {
+  void space() throws Exception {
     final String[] expected = {
       "84:20: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "("),
       "84:27: " + getCheckMessage(MSG_WS_NOT_PRECEDED, ")"),
@@ -63,13 +63,13 @@ public class TypecastParenPadCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test1322879() throws Exception {
+  void test1322879() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputTypecastParenPadWhitespaceAround.java"), expected);
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final TypecastParenPadCheck typecastParenPadCheckObj = new TypecastParenPadCheck();
     final int[] actual = typecastParenPadCheckObj.getAcceptableTokens();
     final int[] expected = {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/WhitespaceAfterCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/WhitespaceAfterCheckTest.java
@@ -27,7 +27,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
+final class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -35,7 +35,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final WhitespaceAfterCheck checkObj = new WhitespaceAfterCheck();
     assertWithMessage("WhitespaceAfterCheck#getRequiredTokens should return empty array by default")
         .that(checkObj.getRequiredTokens())
@@ -43,7 +43,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] expected = {
       "45:39: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, ","),
       "74:29: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, ","),
@@ -52,7 +52,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCast() throws Exception {
+  void cast() throws Exception {
     final String[] expected = {
       "91:20: " + getCheckMessage(MSG_WS_TYPECAST),
     };
@@ -60,7 +60,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMultilineCast() throws Exception {
+  void multilineCast() throws Exception {
     final String[] expected = {
       "14:23: " + getCheckMessage(MSG_WS_TYPECAST),
     };
@@ -68,7 +68,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSemi() throws Exception {
+  void semi() throws Exception {
     final String[] expected = {
       "57:22: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, ";"),
       "57:28: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, ";"),
@@ -78,7 +78,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLiteralWhile() throws Exception {
+  void literalWhile() throws Exception {
     final String[] expected = {
       "46:9: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "while"),
     };
@@ -86,7 +86,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLiteralIf() throws Exception {
+  void literalIf() throws Exception {
     final String[] expected = {
       "25:9: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "if"),
     };
@@ -94,7 +94,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLiteralElse() throws Exception {
+  void literalElse() throws Exception {
     final String[] expected = {
       "34:11: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "else"),
     };
@@ -102,7 +102,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLiteralFor() throws Exception {
+  void literalFor() throws Exception {
     final String[] expected = {
       "58:9: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "for"),
     };
@@ -110,7 +110,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLiteralFinally() throws Exception {
+  void literalFinally() throws Exception {
     final String[] expected = {
       "14:13: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "finally"),
       "17:31: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "finally"),
@@ -119,7 +119,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLiteralReturn() throws Exception {
+  void literalReturn() throws Exception {
     final String[] expected = {
       "17:9: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "return"),
       "21:9: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "return"),
@@ -130,7 +130,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLiteralDo() throws Exception {
+  void literalDo() throws Exception {
     final String[] expected = {
       "70:9: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "do"),
     };
@@ -138,7 +138,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLiteralYield() throws Exception {
+  void literalYield() throws Exception {
     final String[] expected = {
       "17:9: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "yield"),
     };
@@ -147,7 +147,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLiteralSynchronized() throws Exception {
+  void literalSynchronized() throws Exception {
     final String[] expected = {
       "13:9: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "synchronized"),
       "31:9: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "synchronized"),
@@ -157,7 +157,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDoWhile() throws Exception {
+  void doWhile() throws Exception {
     final String[] expected = {
       "25:11: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "while"),
     };
@@ -165,7 +165,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLiteralTry() throws Exception {
+  void literalTry() throws Exception {
     final String[] expected = {
       "20:9: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "try"),
       "24:9: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "try"),
@@ -174,7 +174,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLiteralCatch() throws Exception {
+  void literalCatch() throws Exception {
     final String[] expected = {
       "14:14: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "catch"),
     };
@@ -182,7 +182,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLiteralCase() throws Exception {
+  void literalCase() throws Exception {
     final String[] expected = {
       "15:13: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "case"),
     };
@@ -190,7 +190,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLiteralCase2() throws Exception {
+  void literalCase2() throws Exception {
     final String[] expected = {
       "13:13: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "case"),
     };
@@ -198,7 +198,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyForIterator() throws Exception {
+  void emptyForIterator() throws Exception {
     final String[] expected = {
       "18:30: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, ";"),
       "21:30: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, ";"),
@@ -207,7 +207,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTypeArgumentAndParameterCommas() throws Exception {
+  void typeArgumentAndParameterCommas() throws Exception {
     final String[] expected = {
       "20:20: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, ","),
       "20:22: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, ","),
@@ -217,13 +217,13 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test1322879() throws Exception {
+  void test1322879() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputWhitespaceAfterAround.java"), expected);
   }
 
   @Test
-  public void testCountUnicodeCorrectly() throws Exception {
+  void countUnicodeCorrectly() throws Exception {
     final String[] expected = {
       "14:20: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, ";"),
     };
@@ -232,7 +232,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testVarargs() throws Exception {
+  void varargs() throws Exception {
     final String[] expected = {
       "14:27: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "..."),
       "18:25: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "..."),
@@ -244,7 +244,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSwitchStatements() throws Exception {
+  void switchStatements() throws Exception {
     final String[] expected = {
       "18:9: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "switch"),
       "31:9: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "switch"),
@@ -260,7 +260,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLambdaExpressions() throws Exception {
+  void lambdaExpressions() throws Exception {
     final String[] expected = {
       "17:29: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "->"),
       "19:22: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "->"),
@@ -271,7 +271,7 @@ public class WhitespaceAfterCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWhitespaceAfterWithEmoji() throws Exception {
+  void whitespaceAfterWithEmoji() throws Exception {
     final String[] expected = {
       "13:48: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, ","),
       "13:52: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, ","),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/WhitespaceAroundCheckTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/WhitespaceAroundCheckTest.java
@@ -28,7 +28,7 @@ import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
+final class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -36,7 +36,7 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetRequiredTokens() {
+  void getRequiredTokens() {
     final WhitespaceAroundCheck checkObj = new WhitespaceAroundCheck();
     assertWithMessage(
             "WhitespaceAroundCheck#getRequiredTokens should return empty array by default")
@@ -45,7 +45,7 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testKeywordsAndOperators() throws Exception {
+  void keywordsAndOperators() throws Exception {
     final String[] expected = {
       "32:22: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "="),
       "32:22: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "="),
@@ -93,7 +93,7 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSimpleInput() throws Exception {
+  void simpleInput() throws Exception {
     final String[] expected = {
       "168:26: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "="),
       "169:26: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "="),
@@ -106,7 +106,7 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStartOfTheLine() throws Exception {
+  void startOfTheLine() throws Exception {
     final String[] expected = {
       "25:2: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "{"),
     };
@@ -114,7 +114,7 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBraces() throws Exception {
+  void braces() throws Exception {
     final String[] expected = {
       "53:9: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "while"),
       "70:9: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "for"),
@@ -133,7 +133,7 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBracesInMethodsAndConstructors() throws Exception {
+  void bracesInMethodsAndConstructors() throws Exception {
     final String[] expected = {
       "53:9: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "while"),
       "70:9: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "for"),
@@ -146,7 +146,7 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testArrayInitialization() throws Exception {
+  void arrayInitialization() throws Exception {
     final String[] expected = {
       "21:39: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "{"),
       "25:37: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "{"),
@@ -162,7 +162,7 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGenericsTokensAreFlagged() throws Exception {
+  void genericsTokensAreFlagged() throws Exception {
     final String[] expected = {
       "27:16: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "&"),
       "27:16: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "&"),
@@ -171,13 +171,13 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void test1322879And1649038() throws Exception {
+  void test1322879And1649038() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputWhitespaceAround1.java"), expected);
   }
 
   @Test
-  public void testAllowDoubleBraceInitialization() throws Exception {
+  void allowDoubleBraceInitialization() throws Exception {
     final String[] expected = {
       "31:33: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "}"),
       "32:27: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "{"),
@@ -191,7 +191,7 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIgnoreEnhancedForColon() throws Exception {
+  void ignoreEnhancedForColon() throws Exception {
     final String[] expected = {
       "39:20: " + getCheckMessage(MSG_WS_NOT_PRECEDED, ":"),
     };
@@ -199,7 +199,7 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyTypes() throws Exception {
+  void emptyTypes() throws Exception {
     final String[] expected = {
       "45:94: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "{"),
       "45:95: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "}"),
@@ -213,7 +213,7 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyLoops() throws Exception {
+  void emptyLoops() throws Exception {
     final String[] expected = {
       "56:65: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "{"),
       "56:66: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "}"),
@@ -231,7 +231,7 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSwitchWhitespaceAround() throws Exception {
+  void switchWhitespaceAround() throws Exception {
     final String[] expected = {
       "26:9: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "switch"),
     };
@@ -239,7 +239,7 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDoWhileWhitespaceAround() throws Exception {
+  void doWhileWhitespaceAround() throws Exception {
     final String[] expected = {
       "29:11: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "while"),
     };
@@ -247,13 +247,13 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void allowEmptyMethods() throws Exception {
+  void allowEmptyMethods() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputWhitespaceAround3.java"), expected);
   }
 
   @Test
-  public void testGetAcceptableTokens() {
+  void getAcceptableTokens() {
     final WhitespaceAroundCheck whitespaceAroundCheckObj = new WhitespaceAroundCheck();
     final int[] actual = whitespaceAroundCheckObj.getAcceptableTokens();
     final int[] expected = {
@@ -318,7 +318,7 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowEmptyTypesIsSetToFalseAndNonEmptyClasses() throws Exception {
+  void allowEmptyTypesIsSetToFalseAndNonEmptyClasses() throws Exception {
     final String[] expected = {
       "31:20: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "{"),
       "35:32: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "{"),
@@ -341,7 +341,7 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowEmptyTypesIsSetToTrueAndNonEmptyClasses() throws Exception {
+  void allowEmptyTypesIsSetToTrueAndNonEmptyClasses() throws Exception {
     final String[] expected = {
       "30:20: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "{"),
       "34:32: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "{"),
@@ -360,7 +360,7 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNotAllowEmptyLambdaExpressionsByDefault() throws Exception {
+  void notAllowEmptyLambdaExpressionsByDefault() throws Exception {
     final String[] expected = {
       "27:27: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "{"),
       "27:28: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "}"),
@@ -374,7 +374,7 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllowEmptyLambdaExpressionsWithAllowEmptyLambdaParameter() throws Exception {
+  void allowEmptyLambdaExpressionsWithAllowEmptyLambdaParameter() throws Exception {
     final String[] expected = {
       "32:28: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "{"),
       "32:30: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "}"),
@@ -386,7 +386,7 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWhitespaceAroundLambda() throws Exception {
+  void whitespaceAroundLambda() throws Exception {
     final String[] expected = {
       "28:48: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "->"),
       "28:48: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "->"),
@@ -395,13 +395,13 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWhitespaceAroundEmptyCatchBlock() throws Exception {
+  void whitespaceAroundEmptyCatchBlock() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputWhitespaceAroundCatch.java"), expected);
   }
 
   @Test
-  public void testWhitespaceAroundVarargs() throws Exception {
+  void whitespaceAroundVarargs() throws Exception {
     final String[] expected = {
       "19:29: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "..."),
       "20:37: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "..."),
@@ -416,7 +416,7 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWhitespaceAroundRecords() throws Exception {
+  void whitespaceAroundRecords() throws Exception {
     final String[] expected = {
       "26:23: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "{"),
       "26:24: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "}"),
@@ -445,7 +445,7 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWhitespaceAroundAllowEmptyCompactCtors() throws Exception {
+  void whitespaceAroundAllowEmptyCompactCtors() throws Exception {
     final String[] expected = {
       "26:23: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "{"),
       "26:24: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "}"),
@@ -474,14 +474,14 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWhitespaceAroundRecordsAllowEmptyTypes() throws Exception {
+  void whitespaceAroundRecordsAllowEmptyTypes() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getNonCompilablePath("InputWhitespaceAroundRecordsAllowEmptyTypes.java"), expected);
   }
 
   @Test
-  public void testWhitespaceAroundAllTokens() throws Exception {
+  void whitespaceAroundAllTokens() throws Exception {
     final String[] expected = {
       "27:29: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "<"),
       "27:29: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "<"),
@@ -497,7 +497,7 @@ public class WhitespaceAroundCheckTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWhitespaceAroundAfterEmoji() throws Exception {
+  void whitespaceAroundAfterEmoji() throws Exception {
     final String[] expected = {
       "25:22: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "+"),
       "26:23: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "+"),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/filefilters/BeforeExecutionExclusionFileFilterTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/filefilters/BeforeExecutionExclusionFileFilterTest.java
@@ -28,7 +28,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.util.regex.Pattern;
 import org.junit.jupiter.api.Test;
 
-public class BeforeExecutionExclusionFileFilterTest extends AbstractModuleTestSupport {
+final class BeforeExecutionExclusionFileFilterTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -36,7 +36,7 @@ public class BeforeExecutionExclusionFileFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testAccept() {
+  void accept() {
     final String fileName = "BAD";
     final BeforeExecutionExclusionFileFilter filter =
         createExclusionBeforeExecutionFileFilter(fileName);
@@ -47,7 +47,7 @@ public class BeforeExecutionExclusionFileFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testAcceptOnNullFile() {
+  void acceptOnNullFile() {
     final String fileName = null;
     final BeforeExecutionExclusionFileFilter filter =
         createExclusionBeforeExecutionFileFilter(fileName);
@@ -56,7 +56,7 @@ public class BeforeExecutionExclusionFileFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testReject() {
+  void reject() {
     final String fileName = "Test";
     final BeforeExecutionExclusionFileFilter filter =
         createExclusionBeforeExecutionFileFilter(fileName);
@@ -67,7 +67,7 @@ public class BeforeExecutionExclusionFileFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testFileExclusion() throws Exception {
+  void fileExclusion() throws Exception {
     final String[] filteredViolations = CommonUtil.EMPTY_STRING_ARRAY;
 
     final String[] unfilteredViolations = {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/filters/CsvFilterElementTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/filters/CsvFilterElementTest.java
@@ -25,10 +25,10 @@ import nl.jqno.equalsverifier.EqualsVerifier;
 import nl.jqno.equalsverifier.EqualsVerifierReport;
 import org.junit.jupiter.api.Test;
 
-public class CsvFilterElementTest {
+final class CsvFilterElementTest {
 
   @Test
-  public void testDecideSingle() {
+  void decideSingle() {
     final IntFilterElement filter = new CsvFilterElement("0");
     assertWithMessage("less than").that(filter.accept(-1)).isFalse();
     assertWithMessage("equal").that(filter.accept(0)).isTrue();
@@ -36,7 +36,7 @@ public class CsvFilterElementTest {
   }
 
   @Test
-  public void testDecidePair() {
+  void decidePair() {
     final IntFilterElement filter = new CsvFilterElement("0, 2");
     assertWithMessage("less than").that(filter.accept(-1)).isFalse();
     assertWithMessage("equal 0").that(filter.accept(0)).isTrue();
@@ -45,7 +45,7 @@ public class CsvFilterElementTest {
   }
 
   @Test
-  public void testDecideRange() {
+  void decideRange() {
     final IntFilterElement filter = new CsvFilterElement("0-2");
     assertWithMessage("less than").that(filter.accept(-1)).isFalse();
     assertWithMessage("equal 0").that(filter.accept(0)).isTrue();
@@ -55,7 +55,7 @@ public class CsvFilterElementTest {
   }
 
   @Test
-  public void testDecideEmptyRange() {
+  void decideEmptyRange() {
     final IntFilterElement filter = new CsvFilterElement("2-0");
     assertWithMessage("less than").that(filter.accept(-1)).isFalse();
     assertWithMessage("equal 0").that(filter.accept(0)).isFalse();
@@ -65,7 +65,7 @@ public class CsvFilterElementTest {
   }
 
   @Test
-  public void testDecideRangePlusValue() {
+  void decideRangePlusValue() {
     final IntFilterElement filter = new CsvFilterElement("0-2, 10");
     assertWithMessage("less than").that(filter.accept(-1)).isFalse();
     assertWithMessage("equal 0").that(filter.accept(0)).isTrue();
@@ -76,13 +76,13 @@ public class CsvFilterElementTest {
   }
 
   @Test
-  public void testEmptyChain() {
+  void emptyChain() {
     final CsvFilterElement filter = new CsvFilterElement("");
     assertWithMessage("0").that(filter.accept(0)).isFalse();
   }
 
   @Test
-  public void testEqualsAndHashCode() {
+  void equalsAndHashCode() {
     final EqualsVerifierReport ev =
         EqualsVerifier.forClass(CsvFilterElement.class).usingGetClass().report();
     assertWithMessage("Error: " + ev.getMessage()).that(ev.isSuccessful()).isTrue();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/filters/IntMatchFilterElementTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/filters/IntMatchFilterElementTest.java
@@ -25,10 +25,10 @@ import nl.jqno.equalsverifier.EqualsVerifier;
 import nl.jqno.equalsverifier.EqualsVerifierReport;
 import org.junit.jupiter.api.Test;
 
-public class IntMatchFilterElementTest {
+final class IntMatchFilterElementTest {
 
   @Test
-  public void testDecide() {
+  void decide() {
     final IntFilterElement filter = new IntMatchFilterElement(0);
     assertWithMessage("less than").that(filter.accept(-1)).isFalse();
     assertWithMessage("equal").that(filter.accept(0)).isTrue();
@@ -36,13 +36,13 @@ public class IntMatchFilterElementTest {
   }
 
   @Test
-  public void testEqualsAndHashCode() {
+  void equalsAndHashCode() {
     final EqualsVerifierReport ev = EqualsVerifier.forClass(IntMatchFilterElement.class).report();
     assertWithMessage("Error: " + ev.getMessage()).that(ev.isSuccessful()).isTrue();
   }
 
   @Test
-  public void testToString() {
+  void testToString() {
     final IntFilterElement filter = new IntMatchFilterElement(6);
     assertWithMessage("Invalid toString result")
         .that(filter.toString())
--- a/src/test/java/com/puppycrawl/tools/checkstyle/filters/IntRangeFilterElementTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/filters/IntRangeFilterElementTest.java
@@ -25,10 +25,10 @@ import nl.jqno.equalsverifier.EqualsVerifier;
 import nl.jqno.equalsverifier.EqualsVerifierReport;
 import org.junit.jupiter.api.Test;
 
-public class IntRangeFilterElementTest {
+final class IntRangeFilterElementTest {
 
   @Test
-  public void testDecide() {
+  void decide() {
     final IntFilterElement filter = new IntRangeFilterElement(0, 10);
     assertWithMessage("less than").that(filter.accept(-1)).isFalse();
     assertWithMessage("in range").that(filter.accept(0)).isTrue();
@@ -38,7 +38,7 @@ public class IntRangeFilterElementTest {
   }
 
   @Test
-  public void testDecideSingle() {
+  void decideSingle() {
     final IntFilterElement filter = new IntRangeFilterElement(0, 0);
     assertWithMessage("less than").that(filter.accept(-1)).isFalse();
     assertWithMessage("in range").that(filter.accept(0)).isTrue();
@@ -46,7 +46,7 @@ public class IntRangeFilterElementTest {
   }
 
   @Test
-  public void testDecideEmpty() {
+  void decideEmpty() {
     final IntFilterElement filter = new IntRangeFilterElement(10, 0);
     assertWithMessage("out").that(filter.accept(-1)).isFalse();
     assertWithMessage("out").that(filter.accept(0)).isFalse();
@@ -56,7 +56,7 @@ public class IntRangeFilterElementTest {
   }
 
   @Test
-  public void testEqualsAndHashCode() {
+  void equalsAndHashCode() {
     final EqualsVerifierReport ev =
         EqualsVerifier.forClass(IntRangeFilterElement.class).usingGetClass().report();
     assertWithMessage("Error: " + ev.getMessage()).that(ev.isSuccessful()).isTrue();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/filters/SeverityMatchFilterTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/filters/SeverityMatchFilterTest.java
@@ -28,12 +28,12 @@ import com.puppycrawl.tools.checkstyle.api.SeverityLevel;
 import com.puppycrawl.tools.checkstyle.api.Violation;
 import org.junit.jupiter.api.Test;
 
-public class SeverityMatchFilterTest {
+final class SeverityMatchFilterTest {
 
   private final SeverityMatchFilter filter = new SeverityMatchFilter();
 
   @Test
-  public void testDefault() {
+  void testDefault() {
     final AuditEvent ev = new AuditEvent(this, "Test.java");
     assertWithMessage("no message").that(filter.accept(ev)).isFalse();
     final SeverityLevel errorLevel = SeverityLevel.ERROR;
@@ -49,7 +49,7 @@ public class SeverityMatchFilterTest {
   }
 
   @Test
-  public void testSeverity() {
+  void severity() {
     filter.setSeverity(SeverityLevel.INFO);
     final AuditEvent ev = new AuditEvent(this, "Test.java");
     // event with no message has severity level INFO
@@ -67,7 +67,7 @@ public class SeverityMatchFilterTest {
   }
 
   @Test
-  public void testAcceptOnMatch() {
+  void acceptOnMatch() {
     filter.setSeverity(SeverityLevel.INFO);
     filter.setAcceptOnMatch(false);
     final AuditEvent ev = new AuditEvent(this, "Test.java");
@@ -86,7 +86,7 @@ public class SeverityMatchFilterTest {
   }
 
   @Test
-  public void testConfigure() throws CheckstyleException {
+  void configure() throws CheckstyleException {
     filter.configure(new DefaultConfiguration("test"));
     assertWithMessage("object exists").that(filter).isNotNull();
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressFilterElementTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressFilterElementTest.java
@@ -30,23 +30,23 @@ import nl.jqno.equalsverifier.Warning;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-public class SuppressFilterElementTest {
+final class SuppressFilterElementTest {
 
   private SuppressFilterElement filter;
 
   @BeforeEach
-  public void setUp() {
+  void setUp() {
     filter = new SuppressFilterElement("Test", "Test", null, null, null, null);
   }
 
   @Test
-  public void testDecideDefault() {
+  void decideDefault() {
     final AuditEvent ev = new AuditEvent(this, "Test.java");
     assertWithMessage(ev.getFileName()).that(filter.accept(ev)).isTrue();
   }
 
   @Test
-  public void testDecideViolation() {
+  void decideViolation() {
     final Violation violation = new Violation(1, 0, "", "", null, null, getClass(), null);
     final AuditEvent ev = new AuditEvent(this, "ATest.java", violation);
     // deny because there are matches on file and check names
@@ -54,7 +54,7 @@ public class SuppressFilterElementTest {
   }
 
   @Test
-  public void testDecideByMessage() {
+  void decideByMessage() {
     final Violation violation = new Violation(1, 0, "", "", null, null, getClass(), "Test");
     final AuditEvent ev = new AuditEvent(this, "ATest.java", violation);
     final SuppressFilterElement filter1 =
@@ -66,7 +66,7 @@ public class SuppressFilterElementTest {
   }
 
   @Test
-  public void testDecideByLine() {
+  void decideByLine() {
     final Violation violation = new Violation(10, 10, "", "", null, null, getClass(), null);
     final AuditEvent ev = new AuditEvent(this, "ATest.java", violation);
     final SuppressFilterElement filter1 =
@@ -82,7 +82,7 @@ public class SuppressFilterElementTest {
   }
 
   @Test
-  public void testDecideByColumn() {
+  void decideByColumn() {
     final Violation violation = new Violation(10, 10, "", "", null, null, getClass(), null);
     final AuditEvent ev = new AuditEvent(this, "ATest.java", violation);
     final SuppressFilterElement filter1 =
@@ -96,27 +96,27 @@ public class SuppressFilterElementTest {
   }
 
   @Test
-  public void testDecideByFileNameAndModuleMatchingFileNameNull() {
+  void decideByFileNameAndModuleMatchingFileNameNull() {
     final Violation message = new Violation(10, 10, "", "", null, null, getClass(), null);
     final AuditEvent ev = new AuditEvent(this, null, message);
     assertWithMessage("Filter should accept valid event").that(filter.accept(ev)).isTrue();
   }
 
   @Test
-  public void testDecideByFileNameAndModuleMatchingMessageNull() {
+  void decideByFileNameAndModuleMatchingMessageNull() {
     final AuditEvent ev = new AuditEvent(this, "ATest.java", null);
     assertWithMessage("Filter should accept valid event").that(filter.accept(ev)).isTrue();
   }
 
   @Test
-  public void testDecideByFileNameAndModuleMatchingModuleNull() {
+  void decideByFileNameAndModuleMatchingModuleNull() {
     final Violation violation = new Violation(10, 10, "", "", null, "MyModule", getClass(), null);
     final AuditEvent ev = new AuditEvent(this, "ATest.java", violation);
     assertWithMessage("Filter should not accept invalid event").that(filter.accept(ev)).isFalse();
   }
 
   @Test
-  public void testDecideByFileNameAndModuleMatchingModuleEqual() {
+  void decideByFileNameAndModuleMatchingModuleEqual() {
     final Violation violation = new Violation(10, 10, "", "", null, "MyModule", getClass(), null);
     final AuditEvent ev = new AuditEvent(this, "ATest.java", violation);
     final SuppressFilterElement myFilter =
@@ -126,7 +126,7 @@ public class SuppressFilterElementTest {
   }
 
   @Test
-  public void testDecideByFileNameAndModuleMatchingModuleNotEqual() {
+  void decideByFileNameAndModuleMatchingModuleNotEqual() {
     final Violation message = new Violation(10, 10, "", "", null, "TheirModule", getClass(), null);
     final AuditEvent ev = new AuditEvent(this, "ATest.java", message);
     final SuppressFilterElement myFilter =
@@ -136,14 +136,14 @@ public class SuppressFilterElementTest {
   }
 
   @Test
-  public void testDecideByFileNameAndModuleMatchingRegExpNotMatch() {
+  void decideByFileNameAndModuleMatchingRegExpNotMatch() {
     final Violation message = new Violation(10, 10, "", "", null, null, getClass(), null);
     final AuditEvent ev = new AuditEvent(this, "T1est", message);
     assertWithMessage("Filter should accept valid event").that(filter.accept(ev)).isTrue();
   }
 
   @Test
-  public void testDecideByFileNameAndModuleMatchingRegExpMatch() {
+  void decideByFileNameAndModuleMatchingRegExpMatch() {
     final Violation message = new Violation(10, 10, "", "", null, null, getClass(), null);
     final AuditEvent ev = new AuditEvent(this, "TestSUFFIX", message);
     final SuppressFilterElement myFilter =
@@ -152,7 +152,7 @@ public class SuppressFilterElementTest {
   }
 
   @Test
-  public void testDecideByFileNameAndModuleMatchingCheckRegExpNotMatch() {
+  void decideByFileNameAndModuleMatchingCheckRegExpNotMatch() {
     final Violation message = new Violation(10, 10, "", "", null, null, getClass(), null);
     final AuditEvent ev = new AuditEvent(this, "ATest.java", message);
     final SuppressFilterElement myFilter =
@@ -161,7 +161,7 @@ public class SuppressFilterElementTest {
   }
 
   @Test
-  public void testDecideByFileNameAndModuleMatchingCheckRegExpMatch() {
+  void decideByFileNameAndModuleMatchingCheckRegExpMatch() {
     final Violation message = new Violation(10, 10, "", "", null, null, getClass(), null);
     final AuditEvent ev = new AuditEvent(this, "ATest.java", message);
     final SuppressFilterElement myFilter =
@@ -171,7 +171,7 @@ public class SuppressFilterElementTest {
   }
 
   @Test
-  public void testDecideByFileNameAndSourceNameCheckRegExpNotMatch() {
+  void decideByFileNameAndSourceNameCheckRegExpNotMatch() {
     final Violation message = new Violation(10, 10, "", "", null, null, getClass(), null);
     final AuditEvent ev = new AuditEvent(this, "ATest.java", message);
     final SuppressFilterElement myFilter =
@@ -182,7 +182,7 @@ public class SuppressFilterElementTest {
   }
 
   @Test
-  public void testEquals() {
+  void testEquals() {
     // filterBased is used instead of filter field only to satisfy IntelliJ IDEA Inspection
     // Inspection "Arguments to assertEquals() in wrong order "
     final SuppressFilterElement filterBased =
@@ -213,7 +213,7 @@ public class SuppressFilterElementTest {
   }
 
   @Test
-  public void testEqualsAndHashCode() {
+  void equalsAndHashCode() {
     final EqualsVerifierReport ev =
         EqualsVerifier.forClass(SuppressFilterElement.class)
             .usingGetClass()
--- a/src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressWarningsFilterTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressWarningsFilterTest.java
@@ -31,7 +31,7 @@ import com.puppycrawl.tools.checkstyle.checks.sizes.ParameterNumberCheck;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class SuppressWarningsFilterTest extends AbstractModuleTestSupport {
+final class SuppressWarningsFilterTest extends AbstractModuleTestSupport {
 
   private static final String[] ALL_MESSAGES = {
     "48:5: " + getCheckMessage(MissingJavadocTypeCheck.class, MSG_JAVADOC_MISSING),
@@ -73,14 +73,14 @@ public class SuppressWarningsFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNone() throws Exception {
+  void none() throws Exception {
     final String[] suppressed = CommonUtil.EMPTY_STRING_ARRAY;
     verifySuppressedWithParser(
         getPath("InputSuppressWarningsFilterWithoutFilter.java"), suppressed);
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] suppressed = {
       "56:17: "
           + getCheckMessage(
@@ -102,7 +102,7 @@ public class SuppressWarningsFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSuppressById() throws Exception {
+  void suppressById() throws Exception {
     final String[] suppressedViolationMessages = {
       "49:17: "
           + getCheckMessage(
--- a/src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressWithNearbyCommentFilterTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressWithNearbyCommentFilterTest.java
@@ -22,6 +22,7 @@ package com.puppycrawl.tools.checkstyle.filters;
 import static com.google.common.truth.Truth.assertWithMessage;
 import static com.puppycrawl.tools.checkstyle.checks.naming.AbstractNameCheck.MSG_INVALID_PATTERN;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
 import com.puppycrawl.tools.checkstyle.TreeWalker;
@@ -37,13 +38,12 @@ import com.puppycrawl.tools.checkstyle.internal.utils.TestUtil;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.io.File;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import nl.jqno.equalsverifier.EqualsVerifier;
 import nl.jqno.equalsverifier.EqualsVerifierReport;
 import org.junit.jupiter.api.Test;
 
-public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSupport {
+final class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSupport {
 
   private static final String[] ALL_MESSAGES = {
     "46:17: "
@@ -126,7 +126,7 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testNone() throws Exception {
+  void none() throws Exception {
     final String[] suppressed = CommonUtil.EMPTY_STRING_ARRAY;
     final String[] expected = {
       "36:17: "
@@ -207,7 +207,7 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] suppressed = {
       "46:17: "
           + getCheckMessage(
@@ -235,7 +235,7 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testCheckC() throws Exception {
+  void checkC() throws Exception {
     final String[] suppressed = {
       "46:17: "
           + getCheckMessage(
@@ -249,7 +249,7 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testCheckCpp() throws Exception {
+  void checkCpp() throws Exception {
     final String[] suppressed = {
       "49:17: "
           + getCheckMessage(
@@ -272,7 +272,7 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testUsingVariableMessage() throws Exception {
+  void usingVariableMessage() throws Exception {
     final String[] suppressed = {
       "102:23: " + getCheckMessage(IllegalCatchCheck.class, IllegalCatchCheck.MSG_KEY, "Throwable"),
       "109:11: " + getCheckMessage(IllegalCatchCheck.class, IllegalCatchCheck.MSG_KEY, "Exception"),
@@ -282,7 +282,7 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testUsingNonMatchingVariableMessage() throws Exception {
+  void usingNonMatchingVariableMessage() throws Exception {
     final String[] suppressed = CommonUtil.EMPTY_STRING_ARRAY;
     verifySuppressedWithParser(
         getPath("InputSuppressWithNearbyCommentFilterUsingNonMatchingVariableMessage.java"),
@@ -290,7 +290,7 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testUsingVariableCheckOnNextLine() throws Exception {
+  void usingVariableCheckOnNextLine() throws Exception {
     final String[] suppressed = {
       "61:17: "
           + getCheckMessage(
@@ -302,7 +302,7 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testUsingVariableCheckOnPreviousLine() throws Exception {
+  void usingVariableCheckOnPreviousLine() throws Exception {
     final String[] suppressed = {
       "65:17: "
           + getCheckMessage(
@@ -314,7 +314,7 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testVariableCheckOnVariableNumberOfLines() throws Exception {
+  void variableCheckOnVariableNumberOfLines() throws Exception {
     final String[] suppressed = {
       "74:30: "
           + getCheckMessage(
@@ -336,7 +336,7 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testEqualsAndHashCodeOfTagClass() {
+  void equalsAndHashCodeOfTagClass() {
     final SuppressWithNearbyCommentFilter filter = new SuppressWithNearbyCommentFilter();
     final Object tag =
         getTagsAfterExecution(filter, "filename", "//SUPPRESS CHECKSTYLE ignore").get(0);
@@ -356,7 +356,7 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testInvalidInfluenceFormat() throws Exception {
+  void invalidInfluenceFormat() throws Exception {
     final DefaultConfiguration treeWalkerConfig = createModuleConfig(TreeWalker.class);
     final DefaultConfiguration filterConfig =
         createModuleConfig(SuppressWithNearbyCommentFilter.class);
@@ -381,7 +381,7 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testInfluenceFormat() throws Exception {
+  void influenceFormat() throws Exception {
     final String[] suppressed = {
       "46:17: "
           + getCheckMessage(
@@ -413,7 +413,7 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testInvalidCheckFormat() throws Exception {
+  void invalidCheckFormat() throws Exception {
     final DefaultConfiguration treeWalkerConfig = createModuleConfig(TreeWalker.class);
     final DefaultConfiguration filterConfig =
         createModuleConfig(SuppressWithNearbyCommentFilter.class);
@@ -437,12 +437,11 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testAcceptNullViolation() {
+  void acceptNullViolation() {
     final SuppressWithNearbyCommentFilter filter = new SuppressWithNearbyCommentFilter();
     final FileContents contents =
         new FileContents(
-            new FileText(
-                new File("filename"), Collections.singletonList("//SUPPRESS CHECKSTYLE ignore")));
+            new FileText(new File("filename"), ImmutableList.of("//SUPPRESS CHECKSTYLE ignore")));
     contents.reportSingleLineComment(1, 0);
     final TreeWalkerAuditEvent auditEvent = new TreeWalkerAuditEvent(contents, null, null, null);
     assertWithMessage("Filter should accept null violation")
@@ -451,7 +450,7 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testAcceptNullFileContents() {
+  void acceptNullFileContents() {
     final SuppressWithNearbyCommentFilter filter = new SuppressWithNearbyCommentFilter();
     final FileContents contents = null;
     final TreeWalkerAuditEvent auditEvent =
@@ -461,7 +460,7 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testToStringOfTagClass() {
+  void toStringOfTagClass() {
     final SuppressWithNearbyCommentFilter filter = new SuppressWithNearbyCommentFilter();
     final Object tag =
         getTagsAfterExecution(filter, "filename", "//SUPPRESS CHECKSTYLE ignore").get(0);
@@ -473,7 +472,7 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testToStringOfTagClassWithId() {
+  void toStringOfTagClassWithId() {
     final SuppressWithNearbyCommentFilter filter = new SuppressWithNearbyCommentFilter();
     filter.setIdFormat(".*");
     final Object tag =
@@ -486,14 +485,14 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testUsingTagMessageRegexp() throws Exception {
+  void usingTagMessageRegexp() throws Exception {
     final String[] suppressed = CommonUtil.EMPTY_STRING_ARRAY;
     verifySuppressedWithParser(
         getPath("InputSuppressWithNearbyCommentFilterUsingTagMessageRegexp.java"), suppressed);
   }
 
   @Test
-  public void testSuppressByCheck() throws Exception {
+  void suppressByCheck() throws Exception {
     final String[] suppressedViolationMessages = {
       "41:17: "
           + getCheckMessage(
@@ -536,7 +535,7 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testSuppressById() throws Exception {
+  void suppressById() throws Exception {
     final String[] suppressedViolationMessages = {
       "41:17: "
           + getCheckMessage(
@@ -579,7 +578,7 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testSuppressByCheckAndId() throws Exception {
+  void suppressByCheckAndId() throws Exception {
     final String[] suppressedViolationMessages = {
       "41:17: "
           + getCheckMessage(
@@ -622,7 +621,7 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testSuppressByCheckAndNonMatchingId() throws Exception {
+  void suppressByCheckAndNonMatchingId() throws Exception {
     final String[] suppressedViolationMessages = CommonUtil.EMPTY_STRING_ARRAY;
     final String[] expectedViolationMessages = {
       "41:17: "
@@ -655,7 +654,7 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void tesSuppressByIdAndMessage() throws Exception {
+  void tesSuppressByIdAndMessage() throws Exception {
     final String[] suppressedViolationMessages = {
       "55:17: "
           + getCheckMessage(
@@ -692,7 +691,7 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void tesSuppressByCheckAndMessage() throws Exception {
+  void tesSuppressByCheckAndMessage() throws Exception {
     final String[] suppressedViolationMessages = {
       "55:17: "
           + getCheckMessage(
@@ -729,7 +728,7 @@ public class SuppressWithNearbyCommentFilterTest extends AbstractModuleTestSuppo
   }
 
   @Test
-  public void testTagsAreClearedEachRun() {
+  void tagsAreClearedEachRun() {
     final SuppressWithNearbyCommentFilter suppressionCommentFilter =
         new SuppressWithNearbyCommentFilter();
     final List<?> tags1 =
--- a/src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressWithNearbyTextFilterTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressWithNearbyTextFilterTest.java
@@ -39,7 +39,7 @@ import java.io.IOException;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class SuppressWithNearbyTextFilterTest extends AbstractModuleTestSupport {
+final class SuppressWithNearbyTextFilterTest extends AbstractModuleTestSupport {
 
   private static final String REGEXP_SINGLELINE_CHECK_FORMAT = "this should not appear";
 
@@ -49,7 +49,7 @@ public class SuppressWithNearbyTextFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testDefaultConfig() throws Exception {
+  void defaultConfig() throws Exception {
     final int expectedLineLength = 90;
     final String pattern = "^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$";
 
@@ -77,7 +77,7 @@ public class SuppressWithNearbyTextFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testNearbyTextPattern() throws Exception {
+  void nearbyTextPattern() throws Exception {
     final int expectedLineLength = 90;
 
     final String[] violationMessages = {
@@ -108,7 +108,7 @@ public class SuppressWithNearbyTextFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testCheckPattern() throws Exception {
+  void checkPattern() throws Exception {
     final int expectedLineLength = 80;
 
     final String[] violationMessages = {
@@ -130,7 +130,7 @@ public class SuppressWithNearbyTextFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testMessagePattern() throws Exception {
+  void messagePattern() throws Exception {
     final int expectedLineLength = 90;
 
     final String[] violationMessages = {
@@ -152,7 +152,7 @@ public class SuppressWithNearbyTextFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testIdPattern() throws Exception {
+  void idPattern() throws Exception {
     final int expectedLineLength = 80;
 
     final String[] violationMessages = {
@@ -174,7 +174,7 @@ public class SuppressWithNearbyTextFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testLineRangePositive3() throws Exception {
+  void lineRangePositive3() throws Exception {
     final int expectedLineLength = 92;
 
     final String[] violationMessages = {
@@ -206,7 +206,7 @@ public class SuppressWithNearbyTextFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testLineRangeNegative2() throws Exception {
+  void lineRangeNegative2() throws Exception {
     final int expectedLineLength = 91;
 
     final String[] violationMessages = {
@@ -237,7 +237,7 @@ public class SuppressWithNearbyTextFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testVariableCheckPatternAndLineRange() throws Exception {
+  void variableCheckPatternAndLineRange() throws Exception {
     final int expectedLineLength = 85;
 
     final String[] violationMessages = {
@@ -265,7 +265,7 @@ public class SuppressWithNearbyTextFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testNearbyTextPatternAny() throws Exception {
+  void nearbyTextPatternAny() throws Exception {
     final int expectedLineLength = 76;
 
     final String[] violationMessages = {
@@ -283,7 +283,7 @@ public class SuppressWithNearbyTextFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testNearbyTextPatternCompactVariableCheckPattern() throws Exception {
+  void nearbyTextPatternCompactVariableCheckPattern() throws Exception {
     final String[] violationMessages = {
       "26:13: " + getCheckMessage(MagicNumberCheck.class, MagicNumberCheck.MSG_KEY, "42"),
       "27:13: " + getCheckMessage(MagicNumberCheck.class, MagicNumberCheck.MSG_KEY, "43"),
@@ -302,7 +302,7 @@ public class SuppressWithNearbyTextFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testNearbyTextPatternUrlLineLengthSuppression() throws Exception {
+  void nearbyTextPatternUrlLineLengthSuppression() throws Exception {
     final int expectedLineLength = 90;
 
     final String[] violationMessages = {
@@ -323,7 +323,7 @@ public class SuppressWithNearbyTextFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testInvalidCheckPattern() throws Exception {
+  void invalidCheckPattern() throws Exception {
     final String[] violationAndSuppressedMessages = {
       "18: " + getLineLengthCheckMessage(80, 93),
     };
@@ -343,7 +343,7 @@ public class SuppressWithNearbyTextFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testInvalidIdPattern() throws Exception {
+  void invalidIdPattern() throws Exception {
     final String[] violationAndSuppressedMessages = {
       "18: " + getLineLengthCheckMessage(80, 93),
     };
@@ -363,7 +363,7 @@ public class SuppressWithNearbyTextFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testInvalidMessagePattern() throws Exception {
+  void invalidMessagePattern() throws Exception {
     final String[] violationAndSuppressedMessages = {
       "18: " + getLineLengthCheckMessage(80, 93),
     };
@@ -383,7 +383,7 @@ public class SuppressWithNearbyTextFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testInvalidLineRange() throws Exception {
+  void invalidLineRange() throws Exception {
     final String[] violationAndSuppressedMessages = {
       "18: " + getLineLengthCheckMessage(80, 93),
     };
@@ -410,7 +410,7 @@ public class SuppressWithNearbyTextFilterTest extends AbstractModuleTestSupport
    * {@link AbstractModuleTestSupport#verifyFilterWithInlineConfigParser}.
    */
   @Test
-  public void testAcceptNullViolation() {
+  void acceptNullViolation() {
     final SuppressWithNearbyTextFilter filter = new SuppressWithNearbyTextFilter();
     final AuditEvent auditEvent = new AuditEvent(this);
     assertWithMessage("Filter should accept audit event").that(filter.accept(auditEvent)).isTrue();
@@ -424,7 +424,7 @@ public class SuppressWithNearbyTextFilterTest extends AbstractModuleTestSupport
    * InlineConfigParser} does not allow to specify a non-existing file.
    */
   @Test
-  public void testThrowsIllegalStateExceptionWhenFileNotFound() {
+  void throwsIllegalStateExceptionWhenFileNotFound() {
     final Violation message =
         new Violation(
             1,
@@ -470,7 +470,7 @@ public class SuppressWithNearbyTextFilterTest extends AbstractModuleTestSupport
    * @throws IOException if an error occurs while formatting the path to the input file.
    */
   @Test
-  public void testFilterWithDirectory() throws IOException {
+  void filterWithDirectory() throws IOException {
     final SuppressWithNearbyTextFilter filter = new SuppressWithNearbyTextFilter();
     final AuditEvent event =
         new AuditEvent(
@@ -499,7 +499,7 @@ public class SuppressWithNearbyTextFilterTest extends AbstractModuleTestSupport
    * @throws IOException if an error occurs while formatting the path to the input file.
    */
   @Test
-  public void testSuppressionsAreClearedEachRun() throws IOException {
+  void suppressionsAreClearedEachRun() throws IOException {
     final SuppressWithNearbyTextFilter filter = new SuppressWithNearbyTextFilter();
 
     final List<?> suppressions1 =
@@ -522,7 +522,7 @@ public class SuppressWithNearbyTextFilterTest extends AbstractModuleTestSupport
    * @throws IOException if an error occurs while formatting the path to the input file.
    */
   @Test
-  public void testCachedFileAbsolutePathHasChangedEachRun() throws IOException {
+  void cachedFileAbsolutePathHasChangedEachRun() throws IOException {
     final SuppressWithNearbyTextFilter filter = new SuppressWithNearbyTextFilter();
 
     final String cachedFileAbsolutePath1 =
--- a/src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressWithPlainTextCommentFilterTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressWithPlainTextCommentFilterTest.java
@@ -46,7 +46,7 @@ import nl.jqno.equalsverifier.EqualsVerifier;
 import nl.jqno.equalsverifier.EqualsVerifierReport;
 import org.junit.jupiter.api.Test;
 
-public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSupport {
+final class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSupport {
 
   private static final String MSG_REGEXP_EXCEEDED = "regexp.exceeded";
 
@@ -56,7 +56,7 @@ public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testFilterWithDefaultConfig() throws Exception {
+  void filterWithDefaultConfig() throws Exception {
     final String[] suppressed = {
       "20:7: " + getCheckMessage(FileTabCharacterCheck.class, MSG_CONTAINS_TAB),
       "28:1: " + getCheckMessage(FileTabCharacterCheck.class, MSG_CONTAINS_TAB),
@@ -75,7 +75,7 @@ public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testChangeOffAndOnFormat() throws Exception {
+  void changeOffAndOnFormat() throws Exception {
     final String[] suppressed = {
       "20:7: " + getCheckMessage(FileTabCharacterCheck.class, MSG_CONTAINS_TAB),
       "27:30: " + getCheckMessage(FileTabCharacterCheck.class, MSG_CONTAINS_TAB),
@@ -95,7 +95,7 @@ public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testSuppressionCommentsInXmlFile() throws Exception {
+  void suppressionCommentsInXmlFile() throws Exception {
     final DefaultConfiguration filterCfg =
         createModuleConfig(SuppressWithPlainTextCommentFilter.class);
     filterCfg.addProperty("offCommentFormat", "CS-OFF");
@@ -121,7 +121,7 @@ public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testSuppressionCommentsInPropertiesFile() throws Exception {
+  void suppressionCommentsInPropertiesFile() throws Exception {
     final DefaultConfiguration filterCfg =
         createModuleConfig(SuppressWithPlainTextCommentFilter.class);
     filterCfg.addProperty("offCommentFormat", "# CHECKSTYLE:OFF");
@@ -147,7 +147,7 @@ public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testSuppressionCommentsInSqlFile() throws Exception {
+  void suppressionCommentsInSqlFile() throws Exception {
     final DefaultConfiguration filterCfg =
         createModuleConfig(SuppressWithPlainTextCommentFilter.class);
     filterCfg.addProperty("offCommentFormat", "-- CHECKSTYLE OFF");
@@ -173,7 +173,7 @@ public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testSuppressionCommentsInJavaScriptFile() throws Exception {
+  void suppressionCommentsInJavaScriptFile() throws Exception {
     final String[] suppressed = {
       "22: " + getCheckMessage(RegexpSinglelineCheck.class, MSG_REGEXP_EXCEEDED, ".*\\s===.*"),
     };
@@ -190,7 +190,7 @@ public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testInvalidCheckFormat() throws Exception {
+  void invalidCheckFormat() throws Exception {
     final DefaultConfiguration filterCfg =
         createModuleConfig(SuppressWithPlainTextCommentFilter.class);
     filterCfg.addProperty("checkFormat", "e[l");
@@ -225,7 +225,7 @@ public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testInvalidIdFormat() throws Exception {
+  void invalidIdFormat() throws Exception {
     final DefaultConfiguration filterCfg =
         createModuleConfig(SuppressWithPlainTextCommentFilter.class);
     filterCfg.addProperty("idFormat", "e[l");
@@ -252,7 +252,7 @@ public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testInvalidMessageFormat() throws Exception {
+  void invalidMessageFormat() throws Exception {
     final DefaultConfiguration filterCfg =
         createModuleConfig(SuppressWithPlainTextCommentFilter.class);
     filterCfg.addProperty("messageFormat", "e[l");
@@ -287,7 +287,7 @@ public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testInvalidMessageFormatInSqlFile() throws Exception {
+  void invalidMessageFormatInSqlFile() throws Exception {
     final DefaultConfiguration filterCfg =
         createModuleConfig(SuppressWithPlainTextCommentFilter.class);
     filterCfg.addProperty("onCommentFormat", "CSON (\\w+)");
@@ -321,7 +321,7 @@ public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testAcceptNullViolation() {
+  void acceptNullViolation() {
     final SuppressWithPlainTextCommentFilter filter = new SuppressWithPlainTextCommentFilter();
     final AuditEvent auditEvent = new AuditEvent(this);
     assertWithMessage("Filter should accept audit event").that(filter.accept(auditEvent)).isTrue();
@@ -334,7 +334,7 @@ public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSu
    * the inner type {@code Suppression} here.
    */
   @Test
-  public void testEqualsAndHashCodeOfSuppressionClass() throws ClassNotFoundException {
+  void equalsAndHashCodeOfSuppressionClass() throws ClassNotFoundException {
     final Class<?> suppressionClass =
         TestUtil.getInnerClassType(SuppressWithPlainTextCommentFilter.class, "Suppression");
     final EqualsVerifierReport ev =
@@ -343,7 +343,7 @@ public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testSuppressByCheck() throws Exception {
+  void suppressByCheck() throws Exception {
     final String[] suppressedViolationMessages = {
       "36:1: " + getCheckMessage(FileTabCharacterCheck.class, MSG_CONTAINS_TAB),
     };
@@ -367,7 +367,7 @@ public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testSuppressByModuleId() throws Exception {
+  void suppressByModuleId() throws Exception {
     final String[] suppressedViolationMessages = {
       "33: "
           + getCheckMessage(RegexpSinglelineCheck.class, MSG_REGEXP_EXCEEDED, ".*[a-zA-Z][0-9].*"),
@@ -398,7 +398,7 @@ public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testSuppressByCheckAndModuleId() throws Exception {
+  void suppressByCheckAndModuleId() throws Exception {
     final String[] suppressedViolationMessages = {
       "36:1: " + getCheckMessage(FileTabCharacterCheck.class, MSG_CONTAINS_TAB),
     };
@@ -424,7 +424,7 @@ public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testSuppressByCheckAndNonMatchingModuleId() throws Exception {
+  void suppressByCheckAndNonMatchingModuleId() throws Exception {
     final String[] suppressedViolationMessages = CommonUtil.EMPTY_STRING_ARRAY;
 
     final String[] expectedViolationMessages = {
@@ -448,7 +448,7 @@ public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testSuppressByModuleIdWithNullModuleId() throws Exception {
+  void suppressByModuleIdWithNullModuleId() throws Exception {
     final String[] suppressedViolationMessages = {
       "33: "
           + getCheckMessage(RegexpSinglelineCheck.class, MSG_REGEXP_EXCEEDED, ".*[a-zA-Z][0-9].*"),
@@ -479,7 +479,7 @@ public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testSuppressedByIdJavadocCheck() throws Exception {
+  void suppressedByIdJavadocCheck() throws Exception {
     final String[] suppressedViolationMessages = {
       "28: " + getCheckMessage(JavadocMethodCheck.class, MSG_RETURN_EXPECTED),
       "32:9: " + getCheckMessage(JavadocMethodCheck.class, MSG_UNUSED_TAG, "@param", "unused"),
@@ -499,7 +499,7 @@ public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testAcceptThrowsIllegalStateExceptionAsFileNotFound() {
+  void acceptThrowsIllegalStateExceptionAsFileNotFound() {
     final Violation message =
         new Violation(
             1,
@@ -538,7 +538,7 @@ public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testFilterWithCustomMessageFormat() throws Exception {
+  void filterWithCustomMessageFormat() throws Exception {
     final String[] suppressed = {
       "34:1: " + getCheckMessage(FileTabCharacterCheck.class, MSG_CONTAINS_TAB),
     };
@@ -562,7 +562,7 @@ public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testFilterWithIdAndCustomMessageFormat() throws Exception {
+  void filterWithIdAndCustomMessageFormat() throws Exception {
     final DefaultConfiguration filterCfg =
         createModuleConfig(SuppressWithPlainTextCommentFilter.class);
     filterCfg.addProperty("offCommentFormat", "CHECKSTYLE stop (\\w+) (\\w+)");
@@ -600,7 +600,7 @@ public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testFilterWithCheckAndCustomMessageFormat() throws Exception {
+  void filterWithCheckAndCustomMessageFormat() throws Exception {
     final DefaultConfiguration filterCfg =
         createModuleConfig(SuppressWithPlainTextCommentFilter.class);
     filterCfg.addProperty("offCommentFormat", "CHECKSTYLE stop (\\w+) (\\w+)");
@@ -638,7 +638,7 @@ public class SuppressWithPlainTextCommentFilterTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testFilterWithDirectory() throws IOException {
+  void filterWithDirectory() throws IOException {
     final SuppressWithPlainTextCommentFilter filter = new SuppressWithPlainTextCommentFilter();
     final AuditEvent event =
         new AuditEvent(
--- a/src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressionCommentFilterTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressionCommentFilterTest.java
@@ -51,7 +51,7 @@ import nl.jqno.equalsverifier.EqualsVerifier;
 import nl.jqno.equalsverifier.EqualsVerifierReport;
 import org.junit.jupiter.api.Test;
 
-public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
+final class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
 
   private static final String[] ALL_MESSAGES = {
     "45:17: "
@@ -96,7 +96,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNone() throws Exception {
+  void none() throws Exception {
     final String[] messages = {
       "35:17: "
           + getCheckMessage(
@@ -148,7 +148,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
 
   // Suppress all checks between default comments
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] suppressed = {
       "48:17: "
           + getCheckMessage(
@@ -164,7 +164,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCheckC() throws Exception {
+  void checkC() throws Exception {
     final String[] suppressed = {
       "75:17: "
           + getCheckMessage(
@@ -176,7 +176,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCheckCpp() throws Exception {
+  void checkCpp() throws Exception {
     final String[] suppressed = {
       "48:17: "
           + getCheckMessage(
@@ -188,7 +188,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
 
   // Suppress all checks between CS_OFF and CS_ON
   @Test
-  public void testOffFormat() throws Exception {
+  void offFormat() throws Exception {
     final String[] suppressed = {
       "64:17: "
           + getCheckMessage(
@@ -209,7 +209,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
   // Test suppression of checks of only one type
   //  Suppress only ConstantNameCheck between CS_OFF and CS_ON
   @Test
-  public void testOffFormatCheck() throws Exception {
+  void offFormatCheck() throws Exception {
     final String[] suppressed = {
       "71:30: "
           + getCheckMessage(
@@ -219,7 +219,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testArgumentSuppression() throws Exception {
+  void argumentSuppression() throws Exception {
     final String[] suppressed = {
       "110:11: " + getCheckMessage(IllegalCatchCheck.class, IllegalCatchCheck.MSG_KEY, "Exception"),
     };
@@ -227,7 +227,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExpansion() throws Exception {
+  void expansion() throws Exception {
     final String[] suppressed = {
       "54:17: "
           + getCheckMessage(
@@ -243,7 +243,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMessage() throws Exception {
+  void message() throws Exception {
     final String[] suppressed = CommonUtil.EMPTY_STRING_ARRAY;
     verifySuppressedWithParser("InputSuppressionCommentFilter9.java", suppressed);
   }
@@ -259,7 +259,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEqualsAndHashCodeOfTagClass() {
+  void equalsAndHashCodeOfTagClass() {
     final Object tag = getTagsAfterExecutionOnDefaultFilter("//CHECKSTYLE:OFF").get(0);
     final EqualsVerifierReport ev =
         EqualsVerifier.forClass(tag.getClass()).usingGetClass().report();
@@ -267,7 +267,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testToStringOfTagClass() {
+  void toStringOfTagClass() {
     final Object tag = getTagsAfterExecutionOnDefaultFilter("//CHECKSTYLE:OFF").get(0);
     assertWithMessage("Invalid toString result")
         .that(tag.toString())
@@ -277,7 +277,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testToStringOfTagClassWithMessage() {
+  void toStringOfTagClassWithMessage() {
     final SuppressionCommentFilter filter = new SuppressionCommentFilter();
     filter.setMessageFormat(".*");
     final Object tag = getTagsAfterExecution(filter, "filename", "//CHECKSTYLE:ON").get(0);
@@ -289,7 +289,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCompareToOfTagClass() {
+  void compareToOfTagClass() {
     final List<Comparable<Object>> tags1 =
         getTagsAfterExecutionOnDefaultFilter("//CHECKSTYLE:OFF", " //CHECKSTYLE:ON");
     final Comparable<Object> tag1 = tags1.get(0);
@@ -311,7 +311,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidCheckFormat() throws Exception {
+  void invalidCheckFormat() throws Exception {
     final DefaultConfiguration treeWalkerConfig = createModuleConfig(TreeWalker.class);
     final DefaultConfiguration filterConfig = createModuleConfig(SuppressionCommentFilter.class);
     filterConfig.addProperty("checkFormat", "e[l");
@@ -332,7 +332,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidMessageFormat() throws Exception {
+  void invalidMessageFormat() throws Exception {
     final DefaultConfiguration treeWalkerConfig = createModuleConfig(TreeWalker.class);
     final DefaultConfiguration filterConfig = createModuleConfig(SuppressionCommentFilter.class);
     filterConfig.addProperty("messageFormat", "e[l");
@@ -353,7 +353,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAcceptNullViolation() {
+  void acceptNullViolation() {
     final SuppressionCommentFilter filter = new SuppressionCommentFilter();
     final FileContents contents =
         new FileContents(
@@ -367,7 +367,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAcceptNullFileContents() {
+  void acceptNullFileContents() {
     final SuppressionCommentFilter filter = new SuppressionCommentFilter();
     final FileContents contents = null;
     final TreeWalkerAuditEvent auditEvent =
@@ -377,7 +377,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSuppressByCheck() throws Exception {
+  void suppressByCheck() throws Exception {
     final String[] suppressedViolation = {
       "42:17: "
           + getCheckMessage(
@@ -414,7 +414,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSuppressById() throws Exception {
+  void suppressById() throws Exception {
     final String[] suppressedViolation = {
       "42:17: "
           + getCheckMessage(
@@ -451,7 +451,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSuppressByCheckAndId() throws Exception {
+  void suppressByCheckAndId() throws Exception {
     final String[] suppressedViolation = {
       "42:17: "
           + getCheckMessage(
@@ -488,7 +488,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSuppressByIdAndMessage() throws Exception {
+  void suppressByIdAndMessage() throws Exception {
     final String[] suppressedViolation = {
       "54:17: "
           + getCheckMessage(
@@ -522,7 +522,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSuppressByCheckAndMessage() throws Exception {
+  void suppressByCheckAndMessage() throws Exception {
     final String[] suppressedViolation = {
       "54:17: "
           + getCheckMessage(
@@ -556,7 +556,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFindNearestMatchDontAllowSameColumn() {
+  void findNearestMatchDontAllowSameColumn() {
     final SuppressionCommentFilter suppressionCommentFilter = new SuppressionCommentFilter();
     final FileContents contents =
         new FileContents(
@@ -575,7 +575,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTagsAreClearedEachRun() {
+  void tagsAreClearedEachRun() {
     final SuppressionCommentFilter suppressionCommentFilter = new SuppressionCommentFilter();
     final List<?> tags1 =
         getTagsAfterExecution(suppressionCommentFilter, "filename1", "//CHECKSTYLE:OFF", "line2");
@@ -615,7 +615,7 @@ public class SuppressionCommentFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCachingByFileContentsInstance() throws Exception {
+  void cachingByFileContentsInstance() throws Exception {
 
     final File file = new File(getPath("InputSuppressionCommentFilterSuppressById6.java"));
     final DetailAST rootAst = JavaParser.parseFile(file, JavaParser.Options.WITH_COMMENTS);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressionFilterTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressionFilterTest.java
@@ -39,7 +39,7 @@ import java.net.URL;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
 
-public class SuppressionFilterTest extends AbstractModuleTestSupport {
+final class SuppressionFilterTest extends AbstractModuleTestSupport {
 
   @TempDir public File temporaryFolder;
 
@@ -49,7 +49,7 @@ public class SuppressionFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAccept() throws Exception {
+  void accept() throws Exception {
     final String fileName = getPath("InputSuppressionFilterNone.xml");
     final boolean optional = false;
     final SuppressionFilter filter = createSuppressionFilter(fileName, optional);
@@ -62,7 +62,7 @@ public class SuppressionFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAcceptFalse() throws Exception {
+  void acceptFalse() throws Exception {
     final String fileName = getPath("InputSuppressionFilterSuppress.xml");
     final boolean optional = false;
     final SuppressionFilter filter = createSuppressionFilter(fileName, optional);
@@ -77,7 +77,7 @@ public class SuppressionFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAcceptOnNullFile() throws CheckstyleException {
+  void acceptOnNullFile() throws CheckstyleException {
     final String fileName = null;
     final boolean optional = false;
     final SuppressionFilter filter = createSuppressionFilter(fileName, optional);
@@ -89,7 +89,7 @@ public class SuppressionFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonExistentSuppressionFileWithFalseOptional() {
+  void nonExistentSuppressionFileWithFalseOptional() {
     final String fileName = "non_existent_suppression_file.xml";
     try {
       final boolean optional = false;
@@ -103,7 +103,7 @@ public class SuppressionFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExistingInvalidSuppressionFileWithTrueOptional() throws IOException {
+  void existingInvalidSuppressionFileWithTrueOptional() throws IOException {
     final String fileName = getPath("InputSuppressionFilterInvalidFile.xml");
     try {
       final boolean optional = true;
@@ -118,7 +118,7 @@ public class SuppressionFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExistingSuppressionFileWithTrueOptional() throws Exception {
+  void existingSuppressionFileWithTrueOptional() throws Exception {
     final String fileName = getPath("InputSuppressionFilterNone.xml");
     final boolean optional = true;
     final SuppressionFilter filter = createSuppressionFilter(fileName, optional);
@@ -131,7 +131,7 @@ public class SuppressionFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonExistentSuppressionFileWithTrueOptional() throws Exception {
+  void nonExistentSuppressionFileWithTrueOptional() throws Exception {
     final String fileName = "non_existent_suppression_file.xml";
     final boolean optional = true;
     final SuppressionFilter filter = createSuppressionFilter(fileName, optional);
@@ -144,7 +144,7 @@ public class SuppressionFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonExistentSuppressionUrlWithTrueOptional() throws Exception {
+  void nonExistentSuppressionUrlWithTrueOptional() throws Exception {
     final String fileName = "https://checkstyle.org/non_existent_suppression.xml";
     final boolean optional = true;
     final SuppressionFilter filter = createSuppressionFilter(fileName, optional);
@@ -157,7 +157,7 @@ public class SuppressionFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUseCacheLocalFileExternalResourceContentDoesNotChange() throws Exception {
+  void useCacheLocalFileExternalResourceContentDoesNotChange() throws Exception {
     final DefaultConfiguration filterConfig = createModuleConfig(SuppressionFilter.class);
     filterConfig.addProperty("file", getPath("InputSuppressionFilterNone.xml"));
 
@@ -173,7 +173,7 @@ public class SuppressionFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUseCacheRemoteFileExternalResourceContentDoesNotChange() throws Exception {
+  void useCacheRemoteFileExternalResourceContentDoesNotChange() throws Exception {
     final String[] urlCandidates = {
       "https://checkstyle.org/files/suppressions_none.xml",
       "https://raw.githubusercontent.com/checkstyle/checkstyle/master/src/site/resources/"
@@ -262,7 +262,7 @@ public class SuppressionFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testXpathSuppression() throws Exception {
+  void xpathSuppression() throws Exception {
     for (int test = 1; test <= 6; test++) {
       final String pattern = "^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$";
       final String[] expected = {
@@ -280,7 +280,7 @@ public class SuppressionFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSuppression2() throws Exception {
+  void suppression2() throws Exception {
     final String pattern = "^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$";
     final String[] expected = {
       "19:29: "
@@ -295,7 +295,7 @@ public class SuppressionFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSuppression3() throws Exception {
+  void suppression3() throws Exception {
     final String pattern = "^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$";
     final String[] expected = {
       "19:29: "
--- a/src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressionSingleFilterTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressionSingleFilterTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.checks.regexp.RegexpSinglelineCheck;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class SuppressionSingleFilterTest extends AbstractModuleTestSupport {
+final class SuppressionSingleFilterTest extends AbstractModuleTestSupport {
 
   private static final String FORMAT = "TODO$";
   private static final String MESSAGE =
@@ -39,7 +39,7 @@ public class SuppressionSingleFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefault() throws Exception {
+  void testDefault() throws Exception {
     final String[] suppressed = {
       "25: " + MESSAGE,
     };
@@ -47,7 +47,7 @@ public class SuppressionSingleFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMatching() throws Exception {
+  void matching() throws Exception {
     final String[] suppressed = {
       "25: " + MESSAGE,
     };
@@ -55,31 +55,31 @@ public class SuppressionSingleFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonMatchingLineNumber() throws Exception {
+  void nonMatchingLineNumber() throws Exception {
     final String[] suppressed = CommonUtil.EMPTY_STRING_ARRAY;
     verifySuppressedWithParser(getPath("InputSuppressionSingleFilter4.java"), suppressed);
   }
 
   @Test
-  public void testNonMatchingColumnNumber() throws Exception {
+  void nonMatchingColumnNumber() throws Exception {
     final String[] suppressed = CommonUtil.EMPTY_STRING_ARRAY;
     verifySuppressedWithParser(getPath("InputSuppressionSingleFilter5.java"), suppressed);
   }
 
   @Test
-  public void testNonMatchingFileRegexp() throws Exception {
+  void nonMatchingFileRegexp() throws Exception {
     final String[] suppressed = CommonUtil.EMPTY_STRING_ARRAY;
     verifySuppressedWithParser(getPath("InputSuppressionSingleFilter6.java"), suppressed);
   }
 
   @Test
-  public void testNonMatchingModuleId() throws Exception {
+  void nonMatchingModuleId() throws Exception {
     final String[] suppressed = CommonUtil.EMPTY_STRING_ARRAY;
     verifySuppressedWithParser(getPath("InputSuppressionSingleFilter7.java"), suppressed);
   }
 
   @Test
-  public void testMatchingModuleId() throws Exception {
+  void matchingModuleId() throws Exception {
     final String[] suppressed = {
       "25: " + MESSAGE,
     };
@@ -87,19 +87,19 @@ public class SuppressionSingleFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonMatchingChecks() throws Exception {
+  void nonMatchingChecks() throws Exception {
     final String[] suppressed = CommonUtil.EMPTY_STRING_ARRAY;
     verifySuppressedWithParser(getPath("InputSuppressionSingleFilter8.java"), suppressed);
   }
 
   @Test
-  public void testNotMatchingMessage() throws Exception {
+  void notMatchingMessage() throws Exception {
     final String[] suppressed = CommonUtil.EMPTY_STRING_ARRAY;
     verifySuppressedWithParser(getPath("InputSuppressionSingleFilter9.java"), suppressed);
   }
 
   @Test
-  public void testMatchMessage() throws Exception {
+  void matchMessage() throws Exception {
     final String[] suppressed = {
       "25: " + MESSAGE,
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressionXpathFilterTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressionXpathFilterTest.java
@@ -23,19 +23,19 @@ import static com.google.common.truth.Truth.assertWithMessage;
 import static com.puppycrawl.tools.checkstyle.checks.coding.IllegalTokenTextCheck.MSG_KEY;
 import static com.puppycrawl.tools.checkstyle.checks.naming.AbstractNameCheck.MSG_INVALID_PATTERN;
 
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
 import com.puppycrawl.tools.checkstyle.checks.coding.IllegalTokenTextCheck;
 import com.puppycrawl.tools.checkstyle.checks.naming.ConstantNameCheck;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
-import java.util.Collections;
 import java.util.Set;
 import nl.jqno.equalsverifier.EqualsVerifier;
 import nl.jqno.equalsverifier.EqualsVerifierReport;
 import nl.jqno.equalsverifier.Warning;
 import org.junit.jupiter.api.Test;
 
-public class SuppressionXpathFilterTest extends AbstractModuleTestSupport {
+final class SuppressionXpathFilterTest extends AbstractModuleTestSupport {
 
   private static final String PATTERN = "^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$";
 
@@ -49,7 +49,7 @@ public class SuppressionXpathFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAcceptOne() throws Exception {
+  void acceptOne() throws Exception {
     final String[] suppressed = CommonUtil.EMPTY_STRING_ARRAY;
     verifyFilterWithInlineConfigParser(
         getPath("InputSuppressionXpathFilterAcceptOne.java"),
@@ -58,7 +58,7 @@ public class SuppressionXpathFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAcceptTwo() throws Exception {
+  void acceptTwo() throws Exception {
     final String[] expected = {
       "20:29: "
           + getCheckMessage(
@@ -75,7 +75,7 @@ public class SuppressionXpathFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAcceptOnNullFile() throws Exception {
+  void acceptOnNullFile() throws Exception {
     final String[] suppressed = CommonUtil.EMPTY_STRING_ARRAY;
     verifyFilterWithInlineConfigParser(
         getPath("InputSuppressionXpathFilterAcceptOnNullFile.java"),
@@ -84,7 +84,7 @@ public class SuppressionXpathFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonExistentSuppressionFileWithFalseOptional() throws Exception {
+  void nonExistentSuppressionFileWithFalseOptional() throws Exception {
     final String fileName = getPath("non_existent_suppression_file.xml");
     try {
       final boolean optional = false;
@@ -98,7 +98,7 @@ public class SuppressionXpathFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExistingInvalidSuppressionFileWithTrueOptional() throws Exception {
+  void existingInvalidSuppressionFileWithTrueOptional() throws Exception {
     final String fileName = getPath("InputSuppressionXpathFilterInvalidFile.xml");
     try {
       final boolean optional = true;
@@ -115,7 +115,7 @@ public class SuppressionXpathFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExistingSuppressionFileWithTrueOptional() throws Exception {
+  void existingSuppressionFileWithTrueOptional() throws Exception {
     final String[] suppressed = CommonUtil.EMPTY_STRING_ARRAY;
     verifyFilterWithInlineConfigParser(
         getPath("InputSuppressionXpathFilterAcceptWithOptionalTrue.java"),
@@ -124,7 +124,7 @@ public class SuppressionXpathFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonExistentSuppressionFileWithTrueOptional() throws Exception {
+  void nonExistentSuppressionFileWithTrueOptional() throws Exception {
     final String[] suppressed = CommonUtil.EMPTY_STRING_ARRAY;
     verifyFilterWithInlineConfigParser(
         getPath("InputSuppressionXpathFilterNonExistentFileWithTrueOptional.java"),
@@ -133,7 +133,7 @@ public class SuppressionXpathFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testReject() throws Exception {
+  void reject() throws Exception {
     final String[] suppressed = {
       "20:29: "
           + getCheckMessage(ConstantNameCheck.class, MSG_INVALID_PATTERN, "bad_name", PATTERN),
@@ -145,7 +145,7 @@ public class SuppressionXpathFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEqualsAndHashCode() {
+  void equalsAndHashCode() {
     final EqualsVerifierReport ev =
         EqualsVerifier.forClass(SuppressionXpathFilter.class)
             .usingGetClass()
@@ -156,11 +156,11 @@ public class SuppressionXpathFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExternalResource() throws Exception {
+  void externalResource() throws Exception {
     final boolean optional = false;
     final String fileName = getPath("InputSuppressionXpathFilterIdAndQuery.xml");
     final SuppressionXpathFilter filter = createSuppressionXpathFilter(fileName, optional);
-    final Set<String> expected = Collections.singleton(fileName);
+    final Set<String> expected = ImmutableSet.of(fileName);
     final Set<String> actual = filter.getExternalResourceLocations();
     assertWithMessage("Invalid external resource").that(actual).isEqualTo(expected);
   }
@@ -175,7 +175,7 @@ public class SuppressionXpathFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFalseEncodeString() throws Exception {
+  void falseEncodeString() throws Exception {
     final String pattern = "[^a-zA-z0-9]*";
     final String[] expected = {
       "17:24: " + getCheckMessage(IllegalTokenTextCheck.class, MSG_KEY, pattern),
@@ -206,7 +206,7 @@ public class SuppressionXpathFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFalseEncodeChar() throws Exception {
+  void falseEncodeChar() throws Exception {
     final String pattern = "[^a-zA-z0-9]*";
     final String[] expected = {
       "17:14: " + getCheckMessage(IllegalTokenTextCheck.class, MSG_KEY, pattern),
@@ -229,7 +229,7 @@ public class SuppressionXpathFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testXpathSuppression() throws Exception {
+  void xpathSuppression() throws Exception {
     for (int test = 1; test <= 4; test++) {
 
       final String[] expected = {
@@ -248,7 +248,7 @@ public class SuppressionXpathFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testXpathSuppression2() throws Exception {
+  void xpathSuppression2() throws Exception {
     final String pattern = "[^a-zA-z0-9]*";
     final String[] expected = {
       "18:14: " + getCheckMessage(IllegalTokenTextCheck.class, MSG_KEY, pattern),
@@ -265,7 +265,7 @@ public class SuppressionXpathFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testXpathSuppression3() throws Exception {
+  void xpathSuppression3() throws Exception {
     final String pattern = "[^a-zA-z0-9]*";
     final String[] expected = {
       "18:14: " + getCheckMessage(IllegalTokenTextCheck.class, MSG_KEY, pattern),
@@ -282,7 +282,7 @@ public class SuppressionXpathFilterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testXpathSuppression4() throws Exception {
+  void xpathSuppression4() throws Exception {
     final String[] suppressed = {
       "20:29: "
           + getCheckMessage(ConstantNameCheck.class, MSG_INVALID_PATTERN, "bad_name", PATTERN),
--- a/src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressionXpathSingleFilterTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressionXpathSingleFilterTest.java
@@ -41,7 +41,7 @@ import java.util.regex.Pattern;
 import java.util.regex.PatternSyntaxException;
 import org.junit.jupiter.api.Test;
 
-public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport {
+final class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -49,7 +49,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testMatching() throws Exception {
+  void matching() throws Exception {
     final String[] expected = {
       "19:1: " + getCheckMessage(MissingJavadocTypeCheck.class, MSG_JAVADOC_MISSING),
     };
@@ -65,7 +65,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testNonMatchingTokenType() throws Exception {
+  void nonMatchingTokenType() throws Exception {
     final String[] expected = {
       "19:1: " + getCheckMessage(MissingJavadocTypeCheck.class, MSG_JAVADOC_MISSING),
     };
@@ -79,7 +79,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testNonMatchingLineNumber() throws Exception {
+  void nonMatchingLineNumber() throws Exception {
     final String[] expected = {
       "18:1: " + getCheckMessage(MissingJavadocTypeCheck.class, MSG_JAVADOC_MISSING),
       "21:1: " + getCheckMessage(MissingJavadocTypeCheck.class, MSG_JAVADOC_MISSING),
@@ -96,7 +96,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testNonMatchingColumnNumber() throws Exception {
+  void nonMatchingColumnNumber() throws Exception {
     final String[] expected = {
       "23:11: "
           + getCheckMessage(
@@ -114,7 +114,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testComplexQuery() throws Exception {
+  void complexQuery() throws Exception {
     final String[] expected = {
       "27:21: " + getCheckMessage(MagicNumberCheck.class, MSG_KEY, "3.14"),
       "28:16: " + getCheckMessage(MagicNumberCheck.class, MSG_KEY, "123"),
@@ -130,7 +130,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testIncorrectQuery() {
+  void incorrectQuery() {
     final String xpath = "1@#";
     try {
       final Object test =
@@ -145,7 +145,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testNoQuery() throws Exception {
+  void noQuery() throws Exception {
     final String[] expected = {
       "18:1: " + getCheckMessage(MissingJavadocTypeCheck.class, MSG_JAVADOC_MISSING),
     };
@@ -161,7 +161,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testNullFileName() throws Exception {
+  void nullFileName() throws Exception {
     final String[] expected = {
       "18:1: " + getCheckMessage(MissingJavadocTypeCheck.class, MSG_JAVADOC_MISSING),
     };
@@ -175,7 +175,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testNonMatchingFileRegexp() throws Exception {
+  void nonMatchingFileRegexp() throws Exception {
     final String[] expected = {
       "18:1: " + getCheckMessage(MissingJavadocTypeCheck.class, MSG_JAVADOC_MISSING),
     };
@@ -189,7 +189,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testInvalidFileRegexp() {
+  void invalidFileRegexp() {
     final SuppressionXpathSingleFilter filter = new SuppressionXpathSingleFilter();
     try {
       filter.setFiles("e[l");
@@ -202,7 +202,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testInvalidCheckRegexp() {
+  void invalidCheckRegexp() {
     final SuppressionXpathSingleFilter filter = new SuppressionXpathSingleFilter();
     try {
       filter.setChecks("e[l");
@@ -215,7 +215,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testNullViolation() throws Exception {
+  void nullViolation() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     final String[] suppressed = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -226,7 +226,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testNonMatchingModuleId() throws Exception {
+  void nonMatchingModuleId() throws Exception {
     final String[] expected = {
       "20:1: " + getCheckMessage(MissingJavadocTypeCheck.class, MSG_JAVADOC_MISSING),
     };
@@ -240,7 +240,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testMatchingModuleId() throws Exception {
+  void matchingModuleId() throws Exception {
     final String[] expected = {
       "20:1: " + getCheckMessage(MissingJavadocTypeCheck.class, MSG_JAVADOC_MISSING),
     };
@@ -256,7 +256,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testNonMatchingChecks() throws Exception {
+  void nonMatchingChecks() throws Exception {
     final String[] expected = {
       "19:1: " + getCheckMessage(MissingJavadocTypeCheck.class, MSG_JAVADOC_MISSING),
     };
@@ -270,7 +270,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testNonMatchingFileNameModuleIdAndCheck() throws Exception {
+  void nonMatchingFileNameModuleIdAndCheck() throws Exception {
     final String[] expected = {
       "20:1: " + getCheckMessage(MissingJavadocTypeCheck.class, MSG_JAVADOC_MISSING),
     };
@@ -283,7 +283,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testNullModuleIdAndNonMatchingChecks() throws Exception {
+  void nullModuleIdAndNonMatchingChecks() throws Exception {
     final String[] expected = {
       "20:1: " + getCheckMessage(MissingJavadocTypeCheck.class, MSG_JAVADOC_MISSING),
     };
@@ -296,7 +296,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testDecideByMessage() throws Exception {
+  void decideByMessage() throws Exception {
     final String[] expected = {
       "28:1: " + getCheckMessage(MissingJavadocTypeCheck.class, MSG_JAVADOC_MISSING),
       "30:21: " + getCheckMessage(MagicNumberCheck.class, MSG_KEY, "3.14"),
@@ -315,7 +315,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testThrowException() throws Exception {
+  void throwException() throws Exception {
     final String xpath = "//CLASS_DEF[@text='InputSuppressionXpathSingleFilterComplexQuery']";
     final SuppressionXpathSingleFilter filter =
         createSuppressionXpathSingleFilter(
@@ -341,7 +341,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testAllNullConfiguration() throws Exception {
+  void allNullConfiguration() throws Exception {
     final String[] expected = {
       "18:1: " + getCheckMessage(MissingJavadocTypeCheck.class, MSG_JAVADOC_MISSING),
     };
@@ -355,7 +355,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testDecideByIdAndExpression() throws Exception {
+  void decideByIdAndExpression() throws Exception {
     final String[] expected = {
       "20:1: " + getCheckMessage(MissingJavadocTypeCheck.class, MSG_JAVADOC_MISSING),
     };
@@ -371,7 +371,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testDefaultFileProperty() throws Exception {
+  void defaultFileProperty() throws Exception {
     final String[] expected = {
       "20:1: " + getCheckMessage(MissingJavadocTypeCheck.class, MSG_JAVADOC_MISSING),
     };
@@ -387,7 +387,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testDecideByCheck() throws Exception {
+  void decideByCheck() throws Exception {
     final String[] expected = {
       "18:1: " + getCheckMessage(MissingJavadocTypeCheck.class, MSG_JAVADOC_MISSING),
     };
@@ -403,7 +403,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
   }
 
   @Test
-  public void testDecideById() throws Exception {
+  void decideById() throws Exception {
     final String[] expected = {
       "19:1: " + getCheckMessage(MissingJavadocTypeCheck.class, MSG_JAVADOC_MISSING),
     };
@@ -427,7 +427,7 @@ public class SuppressionXpathSingleFilterTest extends AbstractModuleTestSupport
    * @throws Exception when there is problem to load Input file
    */
   @Test
-  public void testUpdateFilterSettingsInRunTime() throws Exception {
+  void updateFilterSettingsInRunTime() throws Exception {
     final File file = new File(getPath("InputSuppressionXpathSingleFilterComplexQuery.java"));
 
     final SuppressionXpathSingleFilter filter = new SuppressionXpathSingleFilter();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressionsLoaderTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/filters/SuppressionsLoaderTest.java
@@ -36,7 +36,7 @@ import org.junit.jupiter.api.Test;
 import org.xml.sax.InputSource;
 
 /** Tests SuppressionsLoader. */
-public class SuppressionsLoaderTest extends AbstractPathTestSupport {
+final class SuppressionsLoaderTest extends AbstractPathTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -44,7 +44,7 @@ public class SuppressionsLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testNoSuppressions() throws Exception {
+  void noSuppressions() throws Exception {
     final FilterSet fc =
         SuppressionsLoader.loadSuppressions(getPath("InputSuppressionsLoaderNone.xml"));
     final FilterSet fc2 = new FilterSet();
@@ -54,7 +54,7 @@ public class SuppressionsLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testLoadFromUrl() throws Exception {
+  void loadFromUrl() throws Exception {
     final String[] urlCandidates = {
       "https://raw.githubusercontent.com/checkstyle/checkstyle/master/src/site/resources/"
           + "files/suppressions_none.xml",
@@ -78,7 +78,7 @@ public class SuppressionsLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testLoadFromMalformedUrl() {
+  void loadFromMalformedUrl() {
     try {
       SuppressionsLoader.loadSuppressions("http");
       assertWithMessage("exception expected").fail();
@@ -90,7 +90,7 @@ public class SuppressionsLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testLoadFromNonExistentUrl() {
+  void loadFromNonExistentUrl() {
     try {
       SuppressionsLoader.loadSuppressions("http://^%$^* %&% %^&");
       assertWithMessage("exception expected").fail();
@@ -102,7 +102,7 @@ public class SuppressionsLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testMultipleSuppression() throws Exception {
+  void multipleSuppression() throws Exception {
     final FilterSet fc =
         SuppressionsLoader.loadSuppressions(getPath("InputSuppressionsLoaderMultiple.xml"));
     final FilterSet fc2 = new FilterSet();
@@ -128,7 +128,7 @@ public class SuppressionsLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testNoFile() throws IOException {
+  void noFile() throws IOException {
     final String fn = getPath("InputSuppressionsLoaderNoFile.xml");
     try {
       SuppressionsLoader.loadSuppressions(fn);
@@ -148,7 +148,7 @@ public class SuppressionsLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testNoCheck() throws IOException {
+  void noCheck() throws IOException {
     final String fn = getPath("InputSuppressionsLoaderNoCheck.xml");
     try {
       SuppressionsLoader.loadSuppressions(fn);
@@ -168,7 +168,7 @@ public class SuppressionsLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testBadInt() throws IOException {
+  void badInt() throws IOException {
     final String fn = getPath("InputSuppressionsLoaderBadInt.xml");
     try {
       SuppressionsLoader.loadSuppressions(fn);
@@ -219,7 +219,7 @@ public class SuppressionsLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testUnableToFindSuppressions() {
+  void unableToFindSuppressions() {
     final String sourceName = "InputSuppressionsLoaderNone.xml";
 
     try {
@@ -236,7 +236,7 @@ public class SuppressionsLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testUnableToReadSuppressions() {
+  void unableToReadSuppressions() {
     final String sourceName = "InputSuppressionsLoaderNone.xml";
 
     try {
@@ -253,7 +253,7 @@ public class SuppressionsLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testNoCheckNoId() throws IOException {
+  void noCheckNoId() throws IOException {
     final String fn = getPath("InputSuppressionsLoaderNoCheckAndId.xml");
     try {
       SuppressionsLoader.loadSuppressions(fn);
@@ -266,7 +266,7 @@ public class SuppressionsLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testNoCheckYesId() throws Exception {
+  void noCheckYesId() throws Exception {
     final String fn = getPath("InputSuppressionsLoaderId.xml");
     final FilterSet set = SuppressionsLoader.loadSuppressions(fn);
 
@@ -274,7 +274,7 @@ public class SuppressionsLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testInvalidFileFormat() throws IOException {
+  void invalidFileFormat() throws IOException {
     final String fn = getPath("InputSuppressionsLoaderInvalidFile.xml");
     try {
       SuppressionsLoader.loadSuppressions(fn);
@@ -287,7 +287,7 @@ public class SuppressionsLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testLoadFromClasspath() throws Exception {
+  void loadFromClasspath() throws Exception {
     final FilterSet fc =
         SuppressionsLoader.loadSuppressions(getPath("InputSuppressionsLoaderNone.xml"));
     final FilterSet fc2 = new FilterSet();
@@ -297,7 +297,7 @@ public class SuppressionsLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testSettingModuleId() throws Exception {
+  void settingModuleId() throws Exception {
     final FilterSet fc =
         SuppressionsLoader.loadSuppressions(getPath("InputSuppressionsLoaderWithId.xml"));
     final SuppressFilterElement suppressElement =
@@ -308,7 +308,7 @@ public class SuppressionsLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testXpathSuppressions() throws Exception {
+  void xpathSuppressions() throws Exception {
     final String fn = getPath("InputSuppressionsLoaderXpathCorrect.xml");
     final Set<TreeWalkerFilter> filterSet = SuppressionsLoader.loadXpathSuppressions(fn);
 
@@ -325,7 +325,7 @@ public class SuppressionsLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testXpathInvalidFileFormat() throws IOException {
+  void xpathInvalidFileFormat() throws IOException {
     final String fn = getPath("InputSuppressionsLoaderXpathInvalidFile.xml");
     try {
       SuppressionsLoader.loadXpathSuppressions(fn);
@@ -341,7 +341,7 @@ public class SuppressionsLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testXpathNoCheckNoId() throws IOException {
+  void xpathNoCheckNoId() throws IOException {
     final String fn = getPath("InputSuppressionsLoaderXpathNoCheckAndId.xml");
     try {
       SuppressionsLoader.loadXpathSuppressions(fn);
@@ -357,7 +357,7 @@ public class SuppressionsLoaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testXpathNoCheckYesId() throws Exception {
+  void xpathNoCheckYesId() throws Exception {
     final String fn = getPath("InputSuppressionsLoaderXpathId.xml");
     final Set<TreeWalkerFilter> filterSet = SuppressionsLoader.loadXpathSuppressions(fn);
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/filters/XpathFilterElementTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/filters/XpathFilterElementTest.java
@@ -39,13 +39,13 @@ import nl.jqno.equalsverifier.EqualsVerifierReport;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-public class XpathFilterElementTest extends AbstractModuleTestSupport {
+final class XpathFilterElementTest extends AbstractModuleTestSupport {
 
   private File file;
   private FileContents fileContents;
 
   @BeforeEach
-  public void setUp() throws Exception {
+  void setUp() throws Exception {
     file = new File(getPath("InputXpathFilterElementSuppressByXpath.java"));
     fileContents = new FileContents(new FileText(file, StandardCharsets.UTF_8.name()));
   }
@@ -56,7 +56,7 @@ public class XpathFilterElementTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMatching() throws Exception {
+  void matching() throws Exception {
     final String xpath = "//CLASS_DEF[./IDENT[@text='InputXpathFilterElementSuppressByXpath']]";
     final XpathFilterElement filter =
         new XpathFilterElement("InputXpathFilterElementSuppressByXpath", "Test", null, null, xpath);
@@ -65,7 +65,7 @@ public class XpathFilterElementTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonMatchingTokenType() throws Exception {
+  void nonMatchingTokenType() throws Exception {
     final String xpath = "//METHOD_DEF[./IDENT[@text='countTokens']]";
     final XpathFilterElement filter =
         new XpathFilterElement("InputXpathFilterElementSuppressByXpath", "Test", null, null, xpath);
@@ -74,7 +74,7 @@ public class XpathFilterElementTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonMatchingLineNumber() throws Exception {
+  void nonMatchingLineNumber() throws Exception {
     final String xpath = "//CLASS_DEF[./IDENT[@text='InputXpathFilterElementSuppressByXpath']]";
     final XpathFilterElement filter =
         new XpathFilterElement("InputXpathFilterElementSuppressByXpath", "Test", null, null, xpath);
@@ -83,7 +83,7 @@ public class XpathFilterElementTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonMatchingColumnNumber() throws Exception {
+  void nonMatchingColumnNumber() throws Exception {
     final String xpath = "//CLASS_DEF[./IDENT[@text='InputXpathFilterElementSuppressByXpath']]";
     final XpathFilterElement filter =
         new XpathFilterElement("InputXpathFilterElementSuppressByXpath", "Test", null, null, xpath);
@@ -92,7 +92,7 @@ public class XpathFilterElementTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testComplexQuery() throws Exception {
+  void complexQuery() throws Exception {
     final String xpath =
         "//VARIABLE_DEF[./IDENT[@text='pi'] and "
             + "../../IDENT[@text='countTokens']] "
@@ -108,7 +108,7 @@ public class XpathFilterElementTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testInvalidCheckRegexp() {
+  void invalidCheckRegexp() {
     try {
       final Object test = new XpathFilterElement(".*", "e[l", ".*", "moduleId", "query");
       assertWithMessage("Exception is expected but got " + test).fail();
@@ -120,7 +120,7 @@ public class XpathFilterElementTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIncorrectQuery() {
+  void incorrectQuery() {
     final String xpath = "1@#";
     try {
       final Object test =
@@ -135,7 +135,7 @@ public class XpathFilterElementTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoQuery() throws Exception {
+  void noQuery() throws Exception {
     final TreeWalkerAuditEvent event = getEvent(15, 8, TokenTypes.VARIABLE_DEF);
     final XpathFilterElement filter =
         new XpathFilterElement("InputXpathFilterElementSuppressByXpath", "Test", null, null, null);
@@ -143,7 +143,7 @@ public class XpathFilterElementTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNullFileName() {
+  void nullFileName() {
     final XpathFilterElement filter =
         new XpathFilterElement("InputXpathFilterElementSuppressByXpath", "Test", null, null, null);
     final TreeWalkerAuditEvent ev = new TreeWalkerAuditEvent(null, null, null, null);
@@ -151,7 +151,7 @@ public class XpathFilterElementTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonMatchingFileRegexp() throws Exception {
+  void nonMatchingFileRegexp() throws Exception {
     final XpathFilterElement filter =
         new XpathFilterElement("NonMatchingRegexp", "Test", null, null, null);
     final TreeWalkerAuditEvent ev = getEvent(3, 0, TokenTypes.CLASS_DEF);
@@ -159,7 +159,7 @@ public class XpathFilterElementTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonMatchingFilePattern() throws Exception {
+  void nonMatchingFilePattern() throws Exception {
     final Pattern pattern = Pattern.compile("NonMatchingRegexp");
     final XpathFilterElement filter = new XpathFilterElement(pattern, null, null, null, null);
     final TreeWalkerAuditEvent ev = getEvent(3, 0, TokenTypes.CLASS_DEF);
@@ -167,7 +167,7 @@ public class XpathFilterElementTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonMatchingCheckRegexp() throws Exception {
+  void nonMatchingCheckRegexp() throws Exception {
     final XpathFilterElement filter =
         new XpathFilterElement(null, "NonMatchingRegexp", null, null, null);
     final TreeWalkerAuditEvent ev = getEvent(3, 0, TokenTypes.CLASS_DEF);
@@ -175,7 +175,7 @@ public class XpathFilterElementTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonMatchingCheckPattern() throws Exception {
+  void nonMatchingCheckPattern() throws Exception {
     final Pattern pattern = Pattern.compile("NonMatchingRegexp");
     final XpathFilterElement filter = new XpathFilterElement(null, pattern, null, null, null);
     final TreeWalkerAuditEvent ev = getEvent(3, 0, TokenTypes.CLASS_DEF);
@@ -183,7 +183,7 @@ public class XpathFilterElementTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNullViolation() {
+  void nullViolation() {
     final XpathFilterElement filter =
         new XpathFilterElement("InputXpathFilterElementSuppressByXpath", "Test", null, null, null);
     final TreeWalkerAuditEvent ev = new TreeWalkerAuditEvent(null, file.getName(), null, null);
@@ -191,7 +191,7 @@ public class XpathFilterElementTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonMatchingModuleId() throws Exception {
+  void nonMatchingModuleId() throws Exception {
     final XpathFilterElement filter =
         new XpathFilterElement(
             "InputXpathFilterElementSuppressByXpath", "Test", null, "id19", null);
@@ -207,7 +207,7 @@ public class XpathFilterElementTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMatchingModuleId() throws Exception {
+  void matchingModuleId() throws Exception {
     final String xpath = "//CLASS_DEF[./IDENT[@text='InputXpathFilterElementSuppressByXpath']]";
     final XpathFilterElement filter =
         new XpathFilterElement(
@@ -224,7 +224,7 @@ public class XpathFilterElementTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonMatchingChecks() throws Exception {
+  void nonMatchingChecks() throws Exception {
     final String xpath = "NON_MATCHING_QUERY";
     final XpathFilterElement filter =
         new XpathFilterElement(
@@ -241,7 +241,7 @@ public class XpathFilterElementTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNonMatchingFileNameModuleIdAndCheck() throws Exception {
+  void nonMatchingFileNameModuleIdAndCheck() throws Exception {
     final String xpath = "NON_MATCHING_QUERY";
     final XpathFilterElement filter =
         new XpathFilterElement("InputXpathFilterElementSuppressByXpath", null, null, null, xpath);
@@ -250,7 +250,7 @@ public class XpathFilterElementTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNullModuleIdAndNonMatchingChecks() throws Exception {
+  void nullModuleIdAndNonMatchingChecks() throws Exception {
     final String xpath = "NON_MATCHING_QUERY";
     final XpathFilterElement filter =
         new XpathFilterElement(
@@ -260,7 +260,7 @@ public class XpathFilterElementTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDecideByMessage() throws Exception {
+  void decideByMessage() throws Exception {
     final Violation message =
         new Violation(1, 0, TokenTypes.CLASS_DEF, "", "", null, null, null, getClass(), "Test");
     final TreeWalkerAuditEvent ev =
@@ -276,7 +276,7 @@ public class XpathFilterElementTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testThrowException() {
+  void throwException() {
     final String xpath = "//CLASS_DEF[@text='InputXpathFilterElementSuppressByXpath']";
     final XpathFilterElement filter =
         new XpathFilterElement("InputXpathFilterElementSuppressByXpath", "Test", null, null, xpath);
@@ -295,7 +295,7 @@ public class XpathFilterElementTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEqualsAndHashCode() throws Exception {
+  void equalsAndHashCode() throws Exception {
     final XPathEvaluator xpathEvaluator = new XPathEvaluator(Configuration.newConfiguration());
     final EqualsVerifierReport ev =
         EqualsVerifier.forClass(XpathFilterElement.class)
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/AstRegressionTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/AstRegressionTest.java
@@ -30,7 +30,7 @@ import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import org.junit.jupiter.api.Test;
 
-public class AstRegressionTest extends AbstractTreeTestSupport {
+final class AstRegressionTest extends AbstractTreeTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -38,115 +38,115 @@ public class AstRegressionTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testClassAstTree1() throws Exception {
+  void classAstTree1() throws Exception {
     verifyAst(
         getPath("ExpectedRegressionJavaClass1Ast.txt"), getPath("InputRegressionJavaClass1.java"));
   }
 
   @Test
-  public void testClassAstTree2() throws Exception {
+  void classAstTree2() throws Exception {
     verifyAst(
         getPath("ExpectedRegressionJavaClass2Ast.txt"), getPath("InputRegressionJavaClass2.java"));
   }
 
   @Test
-  public void testJava8ClassAstTree1() throws Exception {
+  void java8ClassAstTree1() throws Exception {
     verifyAst(
         getPath("ExpectedRegressionJava8Class1Ast.txt"),
         getPath("InputRegressionJava8Class1.java"));
   }
 
   @Test
-  public void testJava8ClassAstTree2() throws Exception {
+  void java8ClassAstTree2() throws Exception {
     verifyAst(
         getPath("ExpectedRegressionJava8Class2Ast.txt"),
         getPath("InputRegressionJava8Class2.java"));
   }
 
   @Test
-  public void testJava9TryWithResourcesAstTree() throws Exception {
+  void java9TryWithResourcesAstTree() throws Exception {
     verifyAst(
         getPath("ExpectedJava9TryWithResources.txt"),
         getPath("/java9/InputJava9TryWithResources.java"));
   }
 
   @Test
-  public void testAdvanceJava9TryWithResourcesAstTree() throws Exception {
+  void advanceJava9TryWithResourcesAstTree() throws Exception {
     verifyAst(
         getPath("ExpectedAdvanceJava9TryWithResources.txt"),
         getPath("/java9/InputAdvanceJava9TryWithResources.java"));
   }
 
   @Test
-  public void testInputSemicolonBetweenImports() throws Exception {
+  void inputSemicolonBetweenImports() throws Exception {
     verifyAst(
         getPath("ExpectedSemicolonBetweenImportsAst.txt"),
         getNonCompilablePath("InputSemicolonBetweenImports.java"));
   }
 
   @Test
-  public void testInterfaceAstTree1() throws Exception {
+  void interfaceAstTree1() throws Exception {
     verifyAst(
         getPath("ExpectedRegressionJavaInterface1Ast.txt"),
         getPath("InputRegressionJavaInterface1.java"));
   }
 
   @Test
-  public void testInterfaceAstTree2() throws Exception {
+  void interfaceAstTree2() throws Exception {
     verifyAst(
         getPath("ExpectedRegressionJavaInterface2Ast.txt"),
         getPath("InputRegressionJavaInterface2.java"));
   }
 
   @Test
-  public void testJava8InterfaceAstTree1() throws Exception {
+  void java8InterfaceAstTree1() throws Exception {
     verifyAst(
         getPath("ExpectedRegressionJava8Interface1Ast.txt"),
         getPath("InputRegressionJava8Interface1.java"));
   }
 
   @Test
-  public void testEnumAstTree1() throws Exception {
+  void enumAstTree1() throws Exception {
     verifyAst(
         getPath("ExpectedRegressionJavaEnum1Ast.txt"), getPath("InputRegressionJavaEnum1.java"));
   }
 
   @Test
-  public void testEnumAstTree2() throws Exception {
+  void enumAstTree2() throws Exception {
     verifyAst(
         getPath("ExpectedRegressionJavaEnum2Ast.txt"), getPath("InputRegressionJavaEnum2.java"));
   }
 
   @Test
-  public void testAnnotationAstTree1() throws Exception {
+  void annotationAstTree1() throws Exception {
     verifyAst(
         getPath("ExpectedRegressionJavaAnnotation1Ast.txt"),
         getPath("InputRegressionJavaAnnotation1.java"));
   }
 
   @Test
-  public void testTypecast() throws Exception {
+  void typecast() throws Exception {
     verifyAst(
         getPath("ExpectedRegressionJavaTypecastAst.txt"),
         getPath("InputRegressionJavaTypecast.java"));
   }
 
   @Test
-  public void testJava14InstanceofWithPatternMatching() throws Exception {
+  void java14InstanceofWithPatternMatching() throws Exception {
     verifyAst(
         getPath("java14/ExpectedJava14InstanceofWithPatternMatchingAST.txt"),
         getNonCompilablePath("java14/InputJava14InstanceofWithPatternMatching.java"));
   }
 
   @Test
-  public void testCharLiteralSurrogatePair() throws Exception {
+  void charLiteralSurrogatePair() throws Exception {
     verifyAst(
         getPath("ExpectedCharLiteralSurrogatePair.txt"),
         getPath("InputCharLiteralSurrogatePair.java"));
   }
 
   @Test
-  public void testCustomAstTree() throws Exception {
+  void customAstTree() throws Exception {
     verifyAstRaw(getPath("ExpectedRegressionEmptyAst.txt"), "\t");
     verifyAstRaw(getPath("ExpectedRegressionEmptyAst.txt"), "\r\n");
     verifyAstRaw(getPath("ExpectedRegressionEmptyAst.txt"), "\n");
@@ -170,7 +170,7 @@ public class AstRegressionTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testNewlineCr() throws Exception {
+  void newlineCr() throws Exception {
     verifyAst(
         getPath("ExpectedNewlineCrAtEndOfFileAst.txt"),
         getPath("InputAstRegressionNewlineCrAtEndOfFile.java"),
@@ -178,105 +178,105 @@ public class AstRegressionTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testJava14Records() throws Exception {
+  void java14Records() throws Exception {
     verifyAst(
         getPath("java14/ExpectedJava14Records.txt"),
         getNonCompilablePath("java14/InputJava14Records.java"));
   }
 
   @Test
-  public void testJava14RecordsTopLevel() throws Exception {
+  void java14RecordsTopLevel() throws Exception {
     verifyAst(
         getPath("java14/ExpectedJava14RecordsTopLevel.txt"),
         getNonCompilablePath("java14/InputJava14RecordsTopLevel.java"));
   }
 
   @Test
-  public void testJava14LocalRecordAnnotation() throws Exception {
+  void java14LocalRecordAnnotation() throws Exception {
     verifyAst(
         getPath("java14/ExpectedJava14LocalRecordAnnotation.txt"),
         getNonCompilablePath("java14/InputJava14LocalRecordAnnotation.java"));
   }
 
   @Test
-  public void testJava14TextBlocks() throws Exception {
+  void java14TextBlocks() throws Exception {
     verifyAst(
         getPath("java14/ExpectedJava14TextBlocks.txt"),
         getNonCompilablePath("java14/InputJava14TextBlocks.java"));
   }
 
   @Test
-  public void testJava14TextBlocksEscapes() throws Exception {
+  void java14TextBlocksEscapes() throws Exception {
     verifyAst(
         getPath("java14/ExpectedJava14TextBlocksEscapesAreOneChar.txt"),
         getNonCompilablePath("java14/InputJava14TextBlocksEscapesAreOneChar.java"));
   }
 
   @Test
-  public void testJava14SwitchExpression() throws Exception {
+  void java14SwitchExpression() throws Exception {
     verifyAst(
         getPath("java14/ExpectedJava14SwitchExpression.txt"),
         getNonCompilablePath("java14/InputJava14SwitchExpression.java"));
   }
 
   @Test
-  public void testInputJava14TextBlocksTabSize() throws Exception {
+  void inputJava14TextBlocksTabSize() throws Exception {
     verifyAst(
         getPath("java14/ExpectedJava14TextBlocksTabSize.txt"),
         getNonCompilablePath("java14/InputJava14TextBlocksTabSize.java"));
   }
 
   @Test
-  public void testInputEscapedS() throws Exception {
+  void inputEscapedS() throws Exception {
     verifyAst(
         getPath("java14/ExpectedJava14EscapedS.txt"),
         getNonCompilablePath("java14/InputJava14EscapedS.java"));
   }
 
   @Test
-  public void testInputSealedAndPermits() throws Exception {
+  void inputSealedAndPermits() throws Exception {
     verifyAst(
         getPath("java15/ExpectedAstRegressionSealedAndPermits.txt"),
         getNonCompilablePath("java15/InputAstRegressionSealedAndPermits.java"));
   }
 
   @Test
-  public void testInputTopLevelNonSealed() throws Exception {
+  void inputTopLevelNonSealed() throws Exception {
     verifyAst(
         getPath("java15/ExpectedTopLevelNonSealed.txt"),
         getNonCompilablePath("java15/InputTopLevelNonSealed.java"));
   }
 
   @Test
-  public void testPatternVariableWithModifiers() throws Exception {
+  void patternVariableWithModifiers() throws Exception {
     verifyAst(
         getPath("java16/ExpectedPatternVariableWithModifiers.txt"),
         getNonCompilablePath("java16/InputPatternVariableWithModifiers.java"));
   }
 
   @Test
-  public void testInputMethodDefArrayDeclarator() throws Exception {
+  void inputMethodDefArrayDeclarator() throws Exception {
     verifyAst(
         getPath("ExpectedAstRegressionMethodDefArrayDeclarator.txt"),
         getPath("InputAstRegressionMethodDefArrayDeclarator.java"));
   }
 
   @Test
-  public void testInputCstyleArrayDefinition() throws Exception {
+  void inputCstyleArrayDefinition() throws Exception {
     verifyAst(
         getPath("ExpectedAstRegressionCStyleArrayDefinition.txt"),
         getPath("InputAstRegressionCStyleArrayDefinition.java"));
   }
 
   @Test
-  public void testInputAnnotatedMethodVariableArityParam() throws Exception {
+  void inputAnnotatedMethodVariableArityParam() throws Exception {
     verifyAst(
         getPath("ExpectedAstRegressionAnnotatedMethodVariableArityParam.txt"),
         getPath("InputAstRegressionAnnotatedMethodVariableArityParam.java"));
   }
 
   @Test
-  public void testInputManyAlternativesInMultiCatch() throws Exception {
+  void inputManyAlternativesInMultiCatch() throws Exception {
     verifyAst(
         getPath("ExpectedAstRegressionManyAlternativesInMultiCatch.txt"),
         getPath("InputAstRegressionManyAlternativesInMultiCatch.java"));
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/CrAwareLexerTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/CrAwareLexerTest.java
@@ -25,10 +25,10 @@ import org.antlr.v4.runtime.CharStream;
 import org.antlr.v4.runtime.CharStreams;
 import org.junit.jupiter.api.Test;
 
-public class CrAwareLexerTest {
+final class CrAwareLexerTest {
 
   @Test
-  public void testConsumeCarriageReturnZeroCharPositionInLine() {
+  void consumeCarriageReturnZeroCharPositionInLine() {
     final String text = "\r";
     final CharStream charStream = CharStreams.fromString(text);
     final CrAwareLexerSimulator lexer = new CrAwareLexerSimulator(null, null, null, null);
@@ -40,7 +40,7 @@ public class CrAwareLexerTest {
   }
 
   @Test
-  public void testConsumeCarriageReturnNewline() {
+  void consumeCarriageReturnNewline() {
     final String text = "\r";
     final CharStream charStream = CharStreams.fromString(text);
     final CrAwareLexerSimulator lexer = new CrAwareLexerSimulator(null, null, null, null);
@@ -52,7 +52,7 @@ public class CrAwareLexerTest {
   }
 
   @Test
-  public void testConsumeWindowsNewlineZeroCharPositionInLine() {
+  void consumeWindowsNewlineZeroCharPositionInLine() {
     final String text = "\r\n";
     final CharStream charStream = CharStreams.fromString(text);
     final CrAwareLexerSimulator lexer = new CrAwareLexerSimulator(null, null, null, null);
@@ -65,7 +65,7 @@ public class CrAwareLexerTest {
   }
 
   @Test
-  public void testConsumeWindowsNewline() {
+  void consumeWindowsNewline() {
     final String text = "\r\n";
     final CharStream charStream = CharStreams.fromString(text);
     final CrAwareLexerSimulator lexer = new CrAwareLexerSimulator(null, null, null, null);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/EmbeddedNullCharTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/EmbeddedNullCharTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
 /** Tests that embedded nulls in string literals does not halt parsing. */
-public class EmbeddedNullCharTest extends AbstractModuleTestSupport {
+final class EmbeddedNullCharTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class EmbeddedNullCharTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCanParse() throws Exception {
+  void canParse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputEmbeddedNullChar.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/GeneratedJava14LexerTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/GeneratedJava14LexerTest.java
@@ -20,21 +20,21 @@
 package com.puppycrawl.tools.checkstyle.grammar;
 
 import static com.puppycrawl.tools.checkstyle.checks.naming.AbstractNameCheck.MSG_INVALID_PATTERN;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.checks.naming.MemberNameCheck;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import java.nio.charset.Charset;
-import java.nio.charset.StandardCharsets;
 import org.junit.jupiter.api.Assumptions;
 import org.junit.jupiter.api.Test;
 
 /** Tests GeneratedJava14Lexer. */
-public class GeneratedJava14LexerTest extends AbstractModuleTestSupport {
+final class GeneratedJava14LexerTest extends AbstractModuleTestSupport {
 
   /** Is {@code true} if current default encoding is UTF-8. */
   private static final boolean IS_UTF8 =
-      Charset.forName(System.getProperty("file.encoding")).equals(StandardCharsets.UTF_8);
+      Charset.forName(System.getProperty("file.encoding")).equals(UTF_8);
 
   @Override
   protected String getPackageLocation() {
@@ -42,7 +42,7 @@ public class GeneratedJava14LexerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testUnexpectedChar() throws Exception {
+  void unexpectedChar() throws Exception {
     // Encoding problems will occur if default encoding is not UTF-8
     Assumptions.assumeTrue(IS_UTF8, "Problems with encoding may occur");
 
@@ -59,7 +59,7 @@ public class GeneratedJava14LexerTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSemicolonBetweenImports() throws Exception {
+  void semicolonBetweenImports() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(
         getNonCompilablePath("InputSemicolonBetweenImports.java"), expected);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/GeneratedJavaTokenTypesTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/GeneratedJavaTokenTypesTest.java
@@ -20,15 +20,15 @@
 package com.puppycrawl.tools.checkstyle.grammar;
 
 import static com.google.common.truth.Truth.assertWithMessage;
+import static java.util.Collections.lastIndexOfSubList;
+import static java.util.stream.Collectors.toUnmodifiableList;
 
 import com.puppycrawl.tools.checkstyle.grammar.java.JavaLanguageLexer;
 import java.lang.reflect.Field;
 import java.lang.reflect.Modifier;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import java.util.Objects;
-import java.util.stream.Collectors;
 import org.antlr.v4.runtime.VocabularyImpl;
 import org.junit.jupiter.api.Test;
 
@@ -39,7 +39,7 @@ import org.junit.jupiter.api.Test;
  * @noinspectionreason ClassIndependentOfModule - architecture of test modules requires this
  *     structure
  */
-public class GeneratedJavaTokenTypesTest {
+final class GeneratedJavaTokenTypesTest {
 
   /**
    * New tokens must be added onto the end of the list with new numbers, and old tokens must remain
@@ -52,7 +52,7 @@ public class GeneratedJavaTokenTypesTest {
    * <p>Issue: <a href="https://github.com/checkstyle/checkstyle/issues/505">#505</a>
    */
   @Test
-  public void testTokenNumbering() {
+  void tokenNumbering() {
     final String message =
         "A token's number has changed. Please open"
             + " 'GeneratedJavaTokenTypesTest' and confirm which token is at fault.\n"
@@ -305,13 +305,11 @@ public class GeneratedJavaTokenTypesTest {
    * unused tokens and cause Collections#lastIndexOfSubList to return a -1 and fail the test.
    */
   @Test
-  public void testTokenHasBeenAddedToTokensBlockInLexerGrammar() {
+  void tokenHasBeenAddedToTokensBlockInLexerGrammar() {
     final VocabularyImpl vocabulary = (VocabularyImpl) JavaLanguageLexer.VOCABULARY;
     final String[] nullableSymbolicNames = vocabulary.getSymbolicNames();
     final List<String> allTokenNames =
-        Arrays.stream(nullableSymbolicNames)
-            .filter(Objects::nonNull)
-            .collect(Collectors.toUnmodifiableList());
+        Arrays.stream(nullableSymbolicNames).filter(Objects::nonNull).collect(toUnmodifiableList());
 
     // Since the following tokens are not declared in the 'tokens' block,
     // they will always appear last in the list of symbolic names provided
@@ -335,7 +333,7 @@ public class GeneratedJavaTokenTypesTest {
 
     // Get the starting index of the sublist of tokens, or -1 if sublist
     // is not present.
-    final int lastIndexOfSublist = Collections.lastIndexOfSubList(allTokenNames, unusedTokenNames);
+    final int lastIndexOfSublist = lastIndexOfSubList(allTokenNames, unusedTokenNames);
     final int expectedNumberOfUsedTokens = allTokenNames.size() - unusedTokenNames.size();
     final String message =
         "New tokens must be added to the 'tokens' block in the" + " lexer grammar.";
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/HexFloatsTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/HexFloatsTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
 /** Tests hex floats and doubles can be parsed. */
-public class HexFloatsTest extends AbstractModuleTestSupport {
+final class HexFloatsTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class HexFloatsTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCanParse() throws Exception {
+  void canParse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputHexFloat.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/Java14RecordsTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/Java14RecordsTest.java
@@ -23,7 +23,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class Java14RecordsTest extends AbstractModuleTestSupport {
+final class Java14RecordsTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -31,7 +31,7 @@ public class Java14RecordsTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJava14Records() throws Exception {
+  void java14Records() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getNonCompilablePath("InputJava14Records.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/Java7DiamondTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/Java7DiamondTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
 /** Tests Java 7 diamond can be parsed. */
-public class Java7DiamondTest extends AbstractModuleTestSupport {
+final class Java7DiamondTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class Java7DiamondTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCanParse() throws Exception {
+  void canParse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJava7Diamond.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/Java7MultiCatchTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/Java7MultiCatchTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
 /** Tests Java 7 multi-catch can be parsed. */
-public class Java7MultiCatchTest extends AbstractModuleTestSupport {
+final class Java7MultiCatchTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class Java7MultiCatchTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCanParse() throws Exception {
+  void canParse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJava7MultiCatch.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/Java7NumericalLiteralsTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/Java7NumericalLiteralsTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
 /** Tests Java 7 numerical literals can be parsed. */
-public class Java7NumericalLiteralsTest extends AbstractModuleTestSupport {
+final class Java7NumericalLiteralsTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class Java7NumericalLiteralsTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCanParse() throws Exception {
+  void canParse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJava7NumericalLiterals.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/Java7StringSwitchTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/Java7StringSwitchTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
 /** Tests Java 7 String in switch can be parsed. */
-public class Java7StringSwitchTest extends AbstractModuleTestSupport {
+final class Java7StringSwitchTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class Java7StringSwitchTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCanParse() throws Exception {
+  void canParse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJava7StringSwitch.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/Java7TryWithResourcesTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/Java7TryWithResourcesTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
 /** Tests Java 7 try-with-resources can be parsed. */
-public class Java7TryWithResourcesTest extends AbstractModuleTestSupport {
+final class Java7TryWithResourcesTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class Java7TryWithResourcesTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCanParse() throws Exception {
+  void canParse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJava7TryWithResources.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/Java9TryWithResourcesTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/Java9TryWithResourcesTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
 /** Tests Java 9 try-with-resources can be parsed. */
-public class Java9TryWithResourcesTest extends AbstractModuleTestSupport {
+final class Java9TryWithResourcesTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class Java9TryWithResourcesTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCanParse() throws Exception {
+  void canParse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputJava9TryWithResources.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/LineCommentAtTheEndOfFileTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/LineCommentAtTheEndOfFileTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
 /** Checks that file can be parsed, when it ends on line-comment but without new-line. */
-public class LineCommentAtTheEndOfFileTest extends AbstractModuleTestSupport {
+final class LineCommentAtTheEndOfFileTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class LineCommentAtTheEndOfFileTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCanParse() throws Exception {
+  void canParse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputLineCommentAtTheEndOfFile.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/MultiDimensionalArraysInGenericsTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/MultiDimensionalArraysInGenericsTest.java
@@ -23,7 +23,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class MultiDimensionalArraysInGenericsTest extends AbstractModuleTestSupport {
+final class MultiDimensionalArraysInGenericsTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -31,7 +31,7 @@ public class MultiDimensionalArraysInGenericsTest extends AbstractModuleTestSupp
   }
 
   @Test
-  public void testCanParse() throws Exception {
+  void canParse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMultiDimensionalArraysInGenerics.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/UnicodeEscapeTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/UnicodeEscapeTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
 /** Tests that extended unicode escapes can be parsed. */
-public class UnicodeEscapeTest extends AbstractModuleTestSupport {
+final class UnicodeEscapeTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class UnicodeEscapeTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCanParse() throws Exception {
+  void canParse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputUnicodeEscape.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/VarargTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/VarargTest.java
@@ -24,7 +24,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
 /** Tests varargs can be parsed. */
-public class VarargTest extends AbstractModuleTestSupport {
+final class VarargTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class VarargTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCanParse() throws Exception {
+  void canParse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputVararg.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/antlr4/Antlr4AstRegressionTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/antlr4/Antlr4AstRegressionTest.java
@@ -23,7 +23,7 @@ import com.puppycrawl.tools.checkstyle.AbstractTreeTestSupport;
 import com.puppycrawl.tools.checkstyle.JavaParser;
 import org.junit.jupiter.api.Test;
 
-public class Antlr4AstRegressionTest extends AbstractTreeTestSupport {
+final class Antlr4AstRegressionTest extends AbstractTreeTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -31,229 +31,229 @@ public class Antlr4AstRegressionTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testPackage() throws Exception {
+  void testPackage() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionPackage.txt"),
         getPath("InputAntlr4AstRegressionPackage.java"));
   }
 
   @Test
-  public void testSimple() throws Exception {
+  void simple() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionSimple.txt"),
         getPath("InputAntlr4AstRegressionSimple.java"));
   }
 
   @Test
-  public void testAnno() throws Exception {
+  void anno() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionSimpleWithAnno.txt"),
         getPath("InputAntlr4AstRegressionSimpleWithAnno.java"));
   }
 
   @Test
-  public void testImports() throws Exception {
+  void imports() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionImports.txt"),
         getPath("InputAntlr4AstRegressionImports.java"));
   }
 
   @Test
-  public void testConstructorCall() throws Exception {
+  void constructorCall() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionConstructorCall.txt"),
         getPath("InputAntlr4AstRegressionConstructorCall.java"));
   }
 
   @Test
-  public void testMethodCall() throws Exception {
+  void methodCall() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionMethodCall.txt"),
         getPath("InputAntlr4AstRegressionMethodCall.java"));
   }
 
   @Test
-  public void testRegressionJavaClass1() throws Exception {
+  void regressionJavaClass1() throws Exception {
     verifyAst(
         getPath("ExpectedRegressionJavaClass1Ast.txt"), getPath("InputRegressionJavaClass1.java"));
   }
 
   @Test
-  public void testRegressionAnnotationLocation() throws Exception {
+  void regressionAnnotationLocation() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionAnnotationLocation.txt"),
         getPath("InputAntlr4AstRegressionAnnotationLocation.java"));
   }
 
   @Test
-  public void testRegressionKeywordsAndOperators() throws Exception {
+  void regressionKeywordsAndOperators() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionKeywordsAndOperators.txt"),
         getPath("InputAntlr4AstRegressionKeywordsAndOperators.java"));
   }
 
   @Test
-  public void testRegressionDiamondOperators() throws Exception {
+  void regressionDiamondOperators() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionKeywordsAndOperators.txt"),
         getPath("InputAntlr4AstRegressionKeywordsAndOperators.java"));
   }
 
   @Test
-  public void testSingleLineBlocks() throws Exception {
+  void singleLineBlocks() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionSingleLineBlocks.txt"),
         getPath("InputAntlr4AstRegressionSingleLineBlocks.java"));
   }
 
   @Test
-  public void testExpressionList() throws Exception {
+  void expressionList() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionExpressionList.txt"),
         getPath("InputAntlr4AstRegressionExpressionList.java"));
   }
 
   @Test
-  public void testNewTypeTree() throws Exception {
+  void newTypeTree() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionNewTypeTree.txt"),
         getPath("InputAntlr4AstRegressionNewTypeTree.java"));
   }
 
   @Test
-  public void testFallThroughDefault() throws Exception {
+  void fallThroughDefault() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionFallThroughDefault.txt"),
         getPath("InputAntlr4AstRegressionFallThroughDefault.java"));
   }
 
   @Test
-  public void testPackageAnnotation() throws Exception {
+  void packageAnnotation() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionPackageAnnotation.txt"), getPath("package-info.java"));
   }
 
   @Test
-  public void testAnnotationOnSameLine1() throws Exception {
+  void annotationOnSameLine1() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionAnnotationOnSameLine.txt"),
         getPath("InputAntlr4AstRegressionAnnotationOnSameLine.java"));
   }
 
   @Test
-  public void testAnnotationOnSameLine2() throws Exception {
+  void annotationOnSameLine2() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionAnnotationOnSameLine2.txt"),
         getPath("InputAntlr4AstRegressionAnnotationOnSameLine2.java"));
   }
 
   @Test
-  public void testSuppressWarnings() throws Exception {
+  void suppressWarnings() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionSuppressWarnings.txt"),
         getPath("InputAntlr4AstRegressionSuppressWarnings.java"));
   }
 
   @Test
-  public void testBadOverride() throws Exception {
+  void badOverride() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionBadOverride.txt"),
         getPath("InputAntlr4AstRegressionBadOverride.java"));
   }
 
   @Test
-  public void testTrickySwitch() throws Exception {
+  void trickySwitch() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionTrickySwitch.txt"),
         getPath("InputAntlr4AstRegressionTrickySwitch.java"));
   }
 
   @Test
-  public void testExplicitInitialization() throws Exception {
+  void explicitInitialization() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionExplicitInitialization.txt"),
         getPath("InputAntlr4AstRegressionExplicitInitialization.java"));
   }
 
   @Test
-  public void testTypeParams() throws Exception {
+  void typeParams() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionTypeParams.txt"),
         getPath("InputAntlr4AstRegressionTypeParams.java"));
   }
 
   @Test
-  public void testForLoops() throws Exception {
+  void forLoops() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionForLoops.txt"),
         getPath("InputAntlr4AstRegressionForLoops.java"));
   }
 
   @Test
-  public void testIllegalCatch() throws Exception {
+  void illegalCatch() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionIllegalCatch.txt"),
         getPath("InputAntlr4AstRegressionIllegalCatch.java"));
   }
 
   @Test
-  public void testNestedTypeParametersAndArrayDeclarators() throws Exception {
+  void nestedTypeParametersAndArrayDeclarators() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionNestedTypeParametersAndArrayDeclarators.txt"),
         getPath("InputAntlr4AstRegressionNestedTypeParametersAndArrayDeclarators.java"));
   }
 
   @Test
-  public void testNewLineAtEndOfFileCr() throws Exception {
+  void newLineAtEndOfFileCr() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionNewLineAtEndOfFileCr.txt"),
         getPath("InputAntlr4AstRegressionNewLineAtEndOfFileCr.java"));
   }
 
   @Test
-  public void testWeirdCtor() throws Exception {
+  void weirdCtor() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionWeirdCtor.txt"),
         getPath("InputAntlr4AstRegressionWeirdCtor.java"));
   }
 
   @Test
-  public void testAnnotationOnQualifiedTypes() throws Exception {
+  void annotationOnQualifiedTypes() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionAnnotationOnQualifiedTypes.txt"),
         getPath("InputAntlr4AstRegressionAnnotationOnQualifiedTypes.java"));
   }
 
   @Test
-  public void testAnnotationOnArrays() throws Exception {
+  void annotationOnArrays() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionAnnotationOnArrays.txt"),
         getPath("InputAntlr4AstRegressionAnnotationOnArrays.java"));
   }
 
   @Test
-  public void testMethodRefs() throws Exception {
+  void methodRefs() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionMethodRefs.txt"),
         getPath("InputAntlr4AstRegressionMethodRefs.java"));
   }
 
   @Test
-  public void testEmbeddedBlockComments() throws Exception {
+  void embeddedBlockComments() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionEmbeddedBlockComments.txt"),
         getPath("InputAntlr4AstRegressionEmbeddedBlockComments.java"));
   }
 
   @Test
-  public void testJava16LocalEnumAndInterface() throws Exception {
+  void java16LocalEnumAndInterface() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionJava16LocalEnumAndInterface.txt"),
         getNonCompilablePath("InputAntlr4AstRegressionJava16LocalEnumAndInterface.java"));
   }
 
   @Test
-  public void testTrickySwitchWithComments() throws Exception {
+  void trickySwitchWithComments() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionTrickySwitchWithComments.txt"),
         getPath("InputAntlr4AstRegressionTrickySwitchWithComments.java"),
@@ -261,7 +261,7 @@ public class Antlr4AstRegressionTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testCassandraInputWithComments() throws Exception {
+  void cassandraInputWithComments() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionCassandraInputWithComments.txt"),
         getPath("InputAntlr4AstRegressionCassandraInputWithComments.java"),
@@ -269,7 +269,7 @@ public class Antlr4AstRegressionTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testCommentsOnAnnotationsAndEnums() throws Exception {
+  void commentsOnAnnotationsAndEnums() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionCommentsOnAnnotationsAndEnums.txt"),
         getPath("InputAntlr4AstRegressionCommentsOnAnnotationsAndEnums.java"),
@@ -277,7 +277,7 @@ public class Antlr4AstRegressionTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testUncommon() throws Exception {
+  void uncommon() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionUncommon.txt"),
         getNonCompilablePath("InputAntlr4AstRegressionUncommon.java"),
@@ -285,7 +285,7 @@ public class Antlr4AstRegressionTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testUncommon2() throws Exception {
+  void uncommon2() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionUncommon2.txt"),
         getNonCompilablePath("InputAntlr4AstRegressionUncommon2.java"),
@@ -293,7 +293,7 @@ public class Antlr4AstRegressionTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testTrickyYield() throws Exception {
+  void trickyYield() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionTrickyYield.txt"),
         getPath("InputAntlr4AstRegressionTrickyYield.java"),
@@ -301,7 +301,7 @@ public class Antlr4AstRegressionTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testSingleCommaInArrayInit() throws Exception {
+  void singleCommaInArrayInit() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionSingleCommaInArrayInit.txt"),
         getPath("InputAntlr4AstRegressionSingleCommaInArrayInit.java"),
@@ -309,7 +309,7 @@ public class Antlr4AstRegressionTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testUncommon3() throws Exception {
+  void uncommon3() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionUncommon3.txt"),
         getNonCompilablePath("InputAntlr4AstRegressionUncommon3.java"),
@@ -317,7 +317,7 @@ public class Antlr4AstRegressionTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testUncommon4() throws Exception {
+  void uncommon4() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionUncommon4.txt"),
         getPath("InputAntlr4AstRegressionUncommon4.java"),
@@ -325,14 +325,14 @@ public class Antlr4AstRegressionTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testQualifiedConstructorParameter() throws Exception {
+  void qualifiedConstructorParameter() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionQualifiedConstructorParameter.txt"),
         getNonCompilablePath("InputAntlr4AstRegressionQualifiedConstructorParameter.java"));
   }
 
   @Test
-  public void testJava15FinalLocalRecord() throws Exception {
+  void java15FinalLocalRecord() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionJava15FinalLocalRecord.txt"),
         getNonCompilablePath("InputAntlr4AstRegressionJava15FinalLocalRecord.java"),
@@ -340,28 +340,28 @@ public class Antlr4AstRegressionTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testUnusualAnnotation() throws Exception {
+  void unusualAnnotation() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionUnusualAnnotation.txt"),
         getPath("InputAntlr4AstRegressionUnusualAnnotation.java"));
   }
 
   @Test
-  public void testLambda() throws Exception {
+  void lambda() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionLambda.txt"),
         getPath("InputAntlr4AstRegressionLambda.java"));
   }
 
   @Test
-  public void testExpressions() throws Exception {
+  void expressions() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionExpressions.txt"),
         getPath("InputAntlr4AstRegressionExpressions.java"));
   }
 
   @Test
-  public void testInterfaceMemberAlternativePrecedence() throws Exception {
+  void interfaceMemberAlternativePrecedence() throws Exception {
     verifyAst(
         getPath("ExpectedAntlr4AstRegressionInterfaceRecordDef.txt"),
         getNonCompilablePath("InputAntlr4AstRegressionInterfaceRecordDef.java"));
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/antlr4/Java17AstRegressionTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/antlr4/Java17AstRegressionTest.java
@@ -22,7 +22,7 @@ package com.puppycrawl.tools.checkstyle.grammar.antlr4;
 import com.puppycrawl.tools.checkstyle.AbstractTreeTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class Java17AstRegressionTest extends AbstractTreeTestSupport {
+final class Java17AstRegressionTest extends AbstractTreeTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -30,49 +30,49 @@ public class Java17AstRegressionTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testPatternsInSwitch() throws Exception {
+  void patternsInSwitch() throws Exception {
     verifyAst(
         getNonCompilablePath("ExpectedAntlr4AstRegressionPatternsInSwitch.txt"),
         getNonCompilablePath("InputAntlr4AstRegressionPatternsInSwitch.java"));
   }
 
   @Test
-  public void testPatternsInIfStatement() throws Exception {
+  void patternsInIfStatement() throws Exception {
     verifyAst(
         getNonCompilablePath("ExpectedAntlr4AstRegressionPatternsInIfStatement.txt"),
         getNonCompilablePath("InputAntlr4AstRegressionPatternsInIfStatement.java"));
   }
 
   @Test
-  public void testPatternsInWhile() throws Exception {
+  void patternsInWhile() throws Exception {
     verifyAst(
         getNonCompilablePath("ExpectedAntlr4AstRegressionPatternsInWhile.txt"),
         getNonCompilablePath("InputAntlr4AstRegressionPatternsInWhile.java"));
   }
 
   @Test
-  public void testPatternsInTernary() throws Exception {
+  void patternsInTernary() throws Exception {
     verifyAst(
         getNonCompilablePath("ExpectedAntlr4AstRegressionPatternsInTernary.txt"),
         getNonCompilablePath("InputAntlr4AstRegressionPatternsInTernary.java"));
   }
 
   @Test
-  public void testPatternsInFor() throws Exception {
+  void patternsInFor() throws Exception {
     verifyAst(
         getNonCompilablePath("ExpectedAntlr4AstRegressionPatternsInFor.txt"),
         getNonCompilablePath("InputAntlr4AstRegressionPatternsInFor.java"));
   }
 
   @Test
-  public void testPatternMatchingInSwitch() throws Exception {
+  void patternMatchingInSwitch() throws Exception {
     verifyAst(
         getNonCompilablePath("ExpectedAntlr4AstRegressionPatternMatchingInSwitch.txt"),
         getNonCompilablePath("InputAntlr4AstRegressionPatternMatchingInSwitch.java"));
   }
 
   @Test
-  public void testCaseDefault() throws Exception {
+  void caseDefault() throws Exception {
     verifyAst(
         getNonCompilablePath("ExpectedAntlr4AstRegressionCaseDefault.txt"),
         getNonCompilablePath("InputAntlr4AstRegressionCaseDefault.java"));
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/comments/AllBlockCommentsTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/comments/AllBlockCommentsTest.java
@@ -20,6 +20,7 @@
 package com.puppycrawl.tools.checkstyle.grammar.comments;
 
 import static com.google.common.truth.Truth.assertWithMessage;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
@@ -27,13 +28,12 @@ import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.internal.utils.CheckUtil;
-import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.LinkedHashSet;
 import java.util.Set;
 import org.junit.jupiter.api.Test;
 
-public class AllBlockCommentsTest extends AbstractModuleTestSupport {
+final class AllBlockCommentsTest extends AbstractModuleTestSupport {
 
   private static final Set<String> ALL_COMMENTS = new LinkedHashSet<>();
 
@@ -45,10 +45,10 @@ public class AllBlockCommentsTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllBlockComments() throws Exception {
+  void allBlockComments() throws Exception {
     final DefaultConfiguration checkConfig = createModuleConfig(BlockCommentListenerCheck.class);
     final String path = getPath("InputFullOfBlockComments.java");
-    lineSeparator = CheckUtil.getLineSeparatorForFile(path, StandardCharsets.UTF_8);
+    lineSeparator = CheckUtil.getLineSeparatorForFile(path, UTF_8);
     execute(checkConfig, path);
     assertWithMessage("All comments should be empty").that(ALL_COMMENTS).isEmpty();
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/comments/AllSinglelineCommentsTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/comments/AllSinglelineCommentsTest.java
@@ -20,6 +20,7 @@
 package com.puppycrawl.tools.checkstyle.grammar.comments;
 
 import static com.google.common.truth.Truth.assertWithMessage;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
@@ -27,12 +28,11 @@ import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import com.puppycrawl.tools.checkstyle.internal.utils.CheckUtil;
-import java.nio.charset.StandardCharsets;
 import java.util.LinkedHashSet;
 import java.util.Set;
 import org.junit.jupiter.api.Test;
 
-public class AllSinglelineCommentsTest extends AbstractModuleTestSupport {
+final class AllSinglelineCommentsTest extends AbstractModuleTestSupport {
 
   private static final Set<String> ALL_COMMENTS = new LinkedHashSet<>();
 
@@ -44,11 +44,11 @@ public class AllSinglelineCommentsTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllSinglelineComments() throws Exception {
+  void allSinglelineComments() throws Exception {
     final DefaultConfiguration checkConfig =
         createModuleConfig(SinglelineCommentListenerCheck.class);
     final String path = getPath("InputFullOfSinglelineComments.java");
-    lineSeparator = CheckUtil.getLineSeparatorForFile(path, StandardCharsets.UTF_8);
+    lineSeparator = CheckUtil.getLineSeparatorForFile(path, UTF_8);
     execute(checkConfig, path);
     assertWithMessage("All comments should be empty").that(ALL_COMMENTS).isEmpty();
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/comments/CommentsTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/comments/CommentsTest.java
@@ -26,7 +26,7 @@ import com.puppycrawl.tools.checkstyle.JavaParser;
 import com.puppycrawl.tools.checkstyle.api.Comment;
 import org.junit.jupiter.api.Test;
 
-public class CommentsTest extends AbstractTreeTestSupport {
+final class CommentsTest extends AbstractTreeTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -34,7 +34,7 @@ public class CommentsTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testCompareExpectedTreeWithInput1() throws Exception {
+  void compareExpectedTreeWithInput1() throws Exception {
     verifyAst(
         getPath("InputComments1Ast.txt"),
         getPath("InputComments1.java"),
@@ -42,7 +42,7 @@ public class CommentsTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testCompareExpectedTreeWithInput2() throws Exception {
+  void compareExpectedTreeWithInput2() throws Exception {
     verifyAst(
         getPath("InputComments2Ast.txt"),
         getPath("InputComments2.java"),
@@ -50,7 +50,7 @@ public class CommentsTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testToString() {
+  void testToString() {
     final Comment comment = new Comment(new String[] {"value"}, 1, 2, 3);
     assertWithMessage("Invalid toString result")
         .that(comment.toString())
@@ -59,7 +59,7 @@ public class CommentsTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testGetCommentMeasures() {
+  void getCommentMeasures() {
     final String[] commentText = {
       "/**",
       "     * Creates new instance.",
@@ -84,7 +84,7 @@ public class CommentsTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testIntersects() {
+  void intersects() {
     final String[] commentText = {
       "// compute a single number for start and end", "// to simplify conditional logic"
     };
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/java19/Java19AstRegressionTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/java19/Java19AstRegressionTest.java
@@ -22,7 +22,7 @@ package com.puppycrawl.tools.checkstyle.grammar.java19;
 import com.puppycrawl.tools.checkstyle.AbstractTreeTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class Java19AstRegressionTest extends AbstractTreeTestSupport {
+final class Java19AstRegressionTest extends AbstractTreeTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -30,84 +30,84 @@ public class Java19AstRegressionTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testPatternsInSwitch() throws Exception {
+  void patternsInSwitch() throws Exception {
     verifyAst(
         getNonCompilablePath("ExpectedJava19PatternsInSwitchLabels.txt"),
         getNonCompilablePath("InputJava19PatternsInSwitchLabels.java"));
   }
 
   @Test
-  public void testPatternsInNullSwitch1() throws Exception {
+  void patternsInNullSwitch1() throws Exception {
     verifyAst(
         getNonCompilablePath("ExpectedJava19PatternsInNullSwitch1.txt"),
         getNonCompilablePath("InputJava19PatternsInNullSwitch1.java"));
   }
 
   @Test
-  public void testPatternsInNullSwitch2() throws Exception {
+  void patternsInNullSwitch2() throws Exception {
     verifyAst(
         getNonCompilablePath("ExpectedJava19PatternsInNullSwitch2.txt"),
         getNonCompilablePath("InputJava19PatternsInNullSwitch2.java"));
   }
 
   @Test
-  public void testAnnotationsOnBinding() throws Exception {
+  void annotationsOnBinding() throws Exception {
     verifyAst(
         getNonCompilablePath("ExpectedJava19PatternsAnnotationsOnBinding.txt"),
         getNonCompilablePath("InputJava19PatternsAnnotationsOnBinding.java"));
   }
 
   @Test
-  public void testTrickyWhenUsage() throws Exception {
+  void trickyWhenUsage() throws Exception {
     verifyAst(
         getNonCompilablePath("ExpectedJava19PatternsTrickyWhenUsage.txt"),
         getNonCompilablePath("InputJava19PatternsTrickyWhenUsage.java"));
   }
 
   @Test
-  public void testLotsOfOperators() throws Exception {
+  void lotsOfOperators() throws Exception {
     verifyAst(
         getNonCompilablePath("ExpectedJava19BindingsWithLotsOfOperators.txt"),
         getNonCompilablePath("InputJava19BindingsWithLotsOfOperators.java"));
   }
 
   @Test
-  public void testRecordPatternsWithNestedDecomposition() throws Exception {
+  void recordPatternsWithNestedDecomposition() throws Exception {
     verifyAst(
         getPath("ExpectedRecordPatternsPreviewNestedDecomposition.txt"),
         getNonCompilablePath("InputRecordPatternsPreviewNestedDecomposition.java"));
   }
 
   @Test
-  public void testRecordPatternsPreview() throws Exception {
+  void recordPatternsPreview() throws Exception {
     verifyAst(
         getPath("ExpectedRecordPatternsPreview.txt"),
         getNonCompilablePath("InputRecordPatternsPreview.java"));
   }
 
   @Test
-  public void testGenericRecordDecomposition() throws Exception {
+  void genericRecordDecomposition() throws Exception {
     verifyAst(
         getNonCompilablePath("ExpectedGenericRecordDeconstructionPattern.txt"),
         getNonCompilablePath("InputGenericRecordDeconstructionPattern.java"));
   }
 
   @Test
-  public void testGuardsWithExtraParenthesis() throws Exception {
+  void guardsWithExtraParenthesis() throws Exception {
     verifyAst(
         getNonCompilablePath("ExpectedJava19GuardsWithExtraParenthesis.txt"),
         getNonCompilablePath("InputJava19GuardsWithExtraParenthesis.java"));
   }
 
   @Test
-  public void testBindingWithModifiers() throws Exception {
+  void bindingWithModifiers() throws Exception {
     verifyAst(
         getNonCompilablePath("ExpectedJava19BindingWithModifiers.txt"),
         getNonCompilablePath("InputJava19BindingWithModifiers.java"));
   }
 
   @Test
-  public void test() throws Exception {
+  void test() throws Exception {
     verifyAst(
         getNonCompilablePath("ExpectedJava19RecordDecompositionWithConditionInLoops.txt"),
         getNonCompilablePath("InputJava19RecordDecompositionWithConditionInLoops.java"));
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/java20/Java20AstRegressionTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/java20/Java20AstRegressionTest.java
@@ -22,7 +22,7 @@ package com.puppycrawl.tools.checkstyle.grammar.java20;
 import com.puppycrawl.tools.checkstyle.AbstractTreeTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class Java20AstRegressionTest extends AbstractTreeTestSupport {
+final class Java20AstRegressionTest extends AbstractTreeTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -30,14 +30,14 @@ public class Java20AstRegressionTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testRecordDecompositionEnhancedForLoop() throws Exception {
+  void recordDecompositionEnhancedForLoop() throws Exception {
     verifyAst(
         getNonCompilablePath("ExpectedJava20RecordDecompositionEnhancedForLoop.txt"),
         getNonCompilablePath("InputJava20RecordDecompositionEnhancedForLoop.java"));
   }
 
   @Test
-  public void testRecordDecompositionEnhancedForLoopTricky() throws Exception {
+  void recordDecompositionEnhancedForLoopTricky() throws Exception {
     verifyAst(
         getNonCompilablePath("ExpectedJava20RecordDecompositionEnhancedForLoopTricky.txt"),
         getNonCompilablePath("InputJava20RecordDecompositionEnhancedForLoopTricky.java"));
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/java21/Java21AstRegressionTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/java21/Java21AstRegressionTest.java
@@ -22,7 +22,7 @@ package com.puppycrawl.tools.checkstyle.grammar.java21;
 import com.puppycrawl.tools.checkstyle.AbstractTreeTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class Java21AstRegressionTest extends AbstractTreeTestSupport {
+final class Java21AstRegressionTest extends AbstractTreeTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -30,7 +30,7 @@ public class Java21AstRegressionTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void testBasicStringTemplate() throws Exception {
+  void basicStringTemplate() throws Exception {
     verifyAst(
         getNonCompilablePath("ExpectedStringTemplateBasic.txt"),
         getNonCompilablePath("InputStringTemplateBasic.java"));
@@ -42,7 +42,7 @@ public class Java21AstRegressionTest extends AbstractTreeTestSupport {
    * vs. four spaces.
    */
   @Test
-  public void testBasicStringTemplateWithTabs() throws Exception {
+  void basicStringTemplateWithTabs() throws Exception {
     verifyAst(
         getNonCompilablePath("ExpectedStringTemplateBasicWithTabs.txt"),
         getNonCompilablePath("InputStringTemplateBasicWithTabs.java"));
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/java8/AnnotationTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/java8/AnnotationTest.java
@@ -23,7 +23,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class AnnotationTest extends AbstractModuleTestSupport {
+final class AnnotationTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -31,73 +31,73 @@ public class AnnotationTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSimpleTypeAnnotation() throws Exception {
+  void simpleTypeAnnotation() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAnnotations1.java"), expected);
   }
 
   @Test
-  public void testAnnotationOnClass() throws Exception {
+  void annotationOnClass() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAnnotations2.java"), expected);
   }
 
   @Test
-  public void testClassCastTypeAnnotation() throws Exception {
+  void classCastTypeAnnotation() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAnnotations3.java"), expected);
   }
 
   @Test
-  public void testMethodParametersTypeAnnotation() throws Exception {
+  void methodParametersTypeAnnotation() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAnnotations4.java"), expected);
   }
 
   @Test
-  public void testAnnotationInThrows() throws Exception {
+  void annotationInThrows() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAnnotations5.java"), expected);
   }
 
   @Test
-  public void testAnnotationInGeneric() throws Exception {
+  void annotationInGeneric() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAnnotations6.java"), expected);
   }
 
   @Test
-  public void testAnnotationOnConstructorCall() throws Exception {
+  void annotationOnConstructorCall() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAnnotations7.java"), expected);
   }
 
   @Test
-  public void testAnnotationNestedCall() throws Exception {
+  void annotationNestedCall() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAnnotations8.java"), expected);
   }
 
   @Test
-  public void testAnnotationOnWildcards() throws Exception {
+  void annotationOnWildcards() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAnnotations9.java"), expected);
   }
 
   @Test
-  public void testAnnotationInCatchParameters() throws Exception {
+  void annotationInCatchParameters() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAnnotations10.java"), expected);
   }
 
   @Test
-  public void testAnnotationInTypeParameters() throws Exception {
+  void annotationInTypeParameters() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAnnotations11.java"), expected);
   }
 
   @Test
-  public void testAnnotationOnVarargs() throws Exception {
+  void annotationOnVarargs() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAnnotations12.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/java8/AnnotationsOnArrayTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/java8/AnnotationsOnArrayTest.java
@@ -23,7 +23,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class AnnotationsOnArrayTest extends AbstractModuleTestSupport {
+final class AnnotationsOnArrayTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -31,7 +31,7 @@ public class AnnotationsOnArrayTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCanParse() throws Exception {
+  void canParse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputAnnotationsOnArray.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/java8/DefaultMethodsTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/java8/DefaultMethodsTest.java
@@ -23,7 +23,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class DefaultMethodsTest extends AbstractModuleTestSupport {
+final class DefaultMethodsTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -31,13 +31,13 @@ public class DefaultMethodsTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCanParse() throws Exception {
+  void canParse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputDefaultMethods.java"), expected);
   }
 
   @Test
-  public void testSwitch() throws Exception {
+  void testSwitch() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputDefaultMethods2.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/java8/LambdaTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/java8/LambdaTest.java
@@ -23,7 +23,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class LambdaTest extends AbstractModuleTestSupport {
+final class LambdaTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -31,109 +31,109 @@ public class LambdaTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLambdaInVariableInitialization() throws Exception {
+  void lambdaInVariableInitialization() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputLambda1.java"), expected);
   }
 
   @Test
-  public void testWithoutArgsOneLineLambdaBody() throws Exception {
+  void withoutArgsOneLineLambdaBody() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputLambda2.java"), expected);
   }
 
   @Test
-  public void testWithoutArgsFullLambdaBody() throws Exception {
+  void withoutArgsFullLambdaBody() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputLambda3.java"), expected);
   }
 
   @Test
-  public void testWithOneArgWithOneLineBody() throws Exception {
+  void withOneArgWithOneLineBody() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputLambda4.java"), expected);
   }
 
   @Test
-  public void testWithOneArgWithFullBody() throws Exception {
+  void withOneArgWithFullBody() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputLambda5.java"), expected);
   }
 
   @Test
-  public void testWithOneArgWithoutTypeOneLineBody() throws Exception {
+  void withOneArgWithoutTypeOneLineBody() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputLambda6.java"), expected);
   }
 
   @Test
-  public void testWithOneArgWithoutTypeFullBody() throws Exception {
+  void withOneArgWithoutTypeFullBody() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputLambda7.java"), expected);
   }
 
   @Test
-  public void testWithFewArgsWithoutTypeOneLineBody() throws Exception {
+  void withFewArgsWithoutTypeOneLineBody() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputLambda8.java"), expected);
   }
 
   @Test
-  public void testWithFewArgsWithoutTypeFullBody() throws Exception {
+  void withFewArgsWithoutTypeFullBody() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputLambda9.java"), expected);
   }
 
   @Test
-  public void testWithOneArgWithoutParenthesesWithoutTypeOneLineBody() throws Exception {
+  void withOneArgWithoutParenthesesWithoutTypeOneLineBody() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputLambda10.java"), expected);
   }
 
   @Test
-  public void testWithOneArgWithoutParenthesesWithoutTypeFullBody() throws Exception {
+  void withOneArgWithoutParenthesesWithoutTypeFullBody() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputLambda11.java"), expected);
   }
 
   @Test
-  public void testWithFewArgWithTypeOneLine() throws Exception {
+  void withFewArgWithTypeOneLine() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputLambda12.java"), expected);
   }
 
   @Test
-  public void testWithFewArgWithTypeFullBody() throws Exception {
+  void withFewArgWithTypeFullBody() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputLambda13.java"), expected);
   }
 
   @Test
-  public void testWithMultilineBody() throws Exception {
+  void withMultilineBody() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputLambda14.java"), expected);
   }
 
   @Test
-  public void testCasesFromSpec() throws Exception {
+  void casesFromSpec() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputLambda15.java"), expected);
   }
 
   @Test
-  public void testWithTypecast() throws Exception {
+  void withTypecast() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputLambda16.java"), expected);
   }
 
   @Test
-  public void testInAssignment() throws Exception {
+  void inAssignment() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputLambda17.java"), expected);
   }
 
   @Test
-  public void testInTernary() throws Exception {
+  void inTernary() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputLambda18.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/java8/MethodReferencesTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/java8/MethodReferencesTest.java
@@ -23,7 +23,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class MethodReferencesTest extends AbstractModuleTestSupport {
+final class MethodReferencesTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -31,43 +31,43 @@ public class MethodReferencesTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCanParse() throws Exception {
+  void canParse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMethodReferences.java"), expected);
   }
 
   @Test
-  public void testFromSpec() throws Exception {
+  void fromSpec() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMethodReferences2.java"), expected);
   }
 
   @Test
-  public void testGenericInPostfixExpressionBeforeReference() throws Exception {
+  void genericInPostfixExpressionBeforeReference() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMethodReferences3.java"), expected);
   }
 
   @Test
-  public void testArrayAfterGeneric() throws Exception {
+  void arrayAfterGeneric() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMethodReferences4.java"), expected);
   }
 
   @Test
-  public void testFromHibernate() throws Exception {
+  void fromHibernate() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMethodReferences5.java"), expected);
   }
 
   @Test
-  public void testFromSpring() throws Exception {
+  void fromSpring() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMethodReferences6.java"), expected);
   }
 
   @Test
-  public void testMethodReferences7() throws Exception {
+  void methodReferences7() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputMethodReferences7.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/java8/ReceiverParameterTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/java8/ReceiverParameterTest.java
@@ -23,7 +23,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class ReceiverParameterTest extends AbstractModuleTestSupport {
+final class ReceiverParameterTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -31,7 +31,7 @@ public class ReceiverParameterTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCanParse() throws Exception {
+  void canParse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputReceiverParameter.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/java8/TypeUseAnnotationsOnQualifiedTypesTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/java8/TypeUseAnnotationsOnQualifiedTypesTest.java
@@ -23,7 +23,7 @@ import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class TypeUseAnnotationsOnQualifiedTypesTest extends AbstractModuleTestSupport {
+final class TypeUseAnnotationsOnQualifiedTypesTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -31,7 +31,7 @@ public class TypeUseAnnotationsOnQualifiedTypesTest extends AbstractModuleTestSu
   }
 
   @Test
-  public void testCanParse() throws Exception {
+  void canParse() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputTypeUseAnnotationsOnQualifiedTypes.java"), expected);
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/javadoc/GeneratedJavadocTokenTypesTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/javadoc/GeneratedJavadocTokenTypesTest.java
@@ -33,7 +33,7 @@ import org.junit.jupiter.api.Test;
  * @noinspectionreason ClassIndependentOfModule - architecture of test modules requires this
  *     structure
  */
-public class GeneratedJavadocTokenTypesTest {
+final class GeneratedJavadocTokenTypesTest {
 
   private static final String MSG =
       "Ensure that token numbers generated for the elements"
@@ -50,7 +50,7 @@ public class GeneratedJavadocTokenTypesTest {
    * @see "https://github.com/checkstyle/checkstyle/issues/5186"
    */
   @Test
-  public void testTokenNumbers() {
+  void tokenNumbers() {
     assertWithMessage(MSG).that(JavadocParser.LEADING_ASTERISK).isEqualTo(1);
     assertWithMessage(MSG).that(JavadocParser.HTML_COMMENT_START).isEqualTo(2);
     assertWithMessage(MSG).that(JavadocParser.DEPRECATED_CDATA_DO_NOT_USE).isEqualTo(3);
@@ -180,7 +180,7 @@ public class GeneratedJavadocTokenTypesTest {
    * @see "https://github.com/checkstyle/checkstyle/issues/5186"
    */
   @Test
-  public void testRuleNumbers() {
+  void ruleNumbers() {
     assertWithMessage(MSG).that(JavadocParser.RULE_javadoc).isEqualTo(0);
     assertWithMessage(MSG).that(JavadocParser.RULE_htmlElement).isEqualTo(1);
     assertWithMessage(MSG).that(JavadocParser.RULE_htmlElementStart).isEqualTo(2);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/grammar/javadoc/JavadocParseTreeTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/grammar/javadoc/JavadocParseTreeTest.java
@@ -30,7 +30,7 @@ import org.junit.jupiter.api.Test;
  * @noinspection ClassOnlyUsedInOnePackage
  * @noinspectionreason ClassOnlyUsedInOnePackage - class is internal tool, and only used in testing
  */
-public class JavadocParseTreeTest extends AbstractTreeTestSupport {
+final class JavadocParseTreeTest extends AbstractTreeTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -46,402 +46,402 @@ public class JavadocParseTreeTest extends AbstractTreeTestSupport {
   }
 
   @Test
-  public void oneSimpleHtmlTag() throws Exception {
+  void oneSimpleHtmlTag() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedOneSimpleHtmlTagAst.txt"),
         getHtmlPath("InputOneSimpleHtmlTag.javadoc"));
   }
 
   @Test
-  public void textBeforeJavadocTags() throws Exception {
+  void textBeforeJavadocTags() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedTextBeforeJavadocTagsAst.txt"),
         getDocPath("InputTextBeforeJavadocTags.javadoc"));
   }
 
   @Test
-  public void customJavadocTags() throws Exception {
+  void customJavadocTags() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedCustomJavadocTagsAst.txt"),
         getDocPath("InputCustomJavadocTags.javadoc"));
   }
 
   @Test
-  public void javadocTagDescriptionWithInlineTags() throws Exception {
+  void javadocTagDescriptionWithInlineTags() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedJavadocTagDescriptionWithInlineTagsAst.txt"),
         getDocPath("InputJavadocTagDescriptionWithInlineTags.javadoc"));
   }
 
   @Test
-  public void leadingAsterisks() throws Exception {
+  void leadingAsterisks() throws Exception {
     verifyJavadocTree(
         getPath("expectedLeadingAsterisksAst.txt"), getPath("InputLeadingAsterisks.javadoc"));
   }
 
   @Test
-  public void authorWithMailto() throws Exception {
+  void authorWithMailto() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedAuthorWithMailtoAst.txt"), getDocPath("InputAuthorWithMailto.javadoc"));
   }
 
   @Test
-  public void htmlTagsInParagraph() throws Exception {
+  void htmlTagsInParagraph() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedHtmlTagsInParagraphAst.txt"),
         getHtmlPath("InputHtmlTagsInParagraph.javadoc"));
   }
 
   @Test
-  public void linkInlineTags() throws Exception {
+  void linkInlineTags() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedLinkInlineTagsAst.txt"), getDocPath("InputLinkInlineTags.javadoc"));
   }
 
   @Test
-  public void seeReferenceWithFewNestedClasses() throws Exception {
+  void seeReferenceWithFewNestedClasses() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedSeeReferenceWithFewNestedClassesAst.txt"),
         getDocPath("InputSeeReferenceWithFewNestedClasses.javadoc"));
   }
 
   @Test
-  public void paramWithGeneric() throws Exception {
+  void paramWithGeneric() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedParamWithGenericAst.txt"), getDocPath("InputParamWithGeneric.javadoc"));
   }
 
   @Test
-  public void serial() throws Exception {
+  void serial() throws Exception {
     verifyJavadocTree(getDocPath("expectedSerialAst.txt"), getDocPath("InputSerial.javadoc"));
   }
 
   @Test
-  public void since() throws Exception {
+  void since() throws Exception {
     verifyJavadocTree(getDocPath("expectedSinceAst.txt"), getDocPath("InputSince.javadoc"));
   }
 
   @Test
-  public void unclosedAndClosedParagraphs() throws Exception {
+  void unclosedAndClosedParagraphs() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedUnclosedAndClosedParagraphsAst.txt"),
         getHtmlPath("InputUnclosedAndClosedParagraphs.javadoc"));
   }
 
   @Test
-  public void listWithUnclosedItemInUnclosedParagraph() throws Exception {
+  void listWithUnclosedItemInUnclosedParagraph() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedListWithUnclosedItemInUnclosedParagraphAst.txt"),
         getHtmlPath("InputListWithUnclosedItemInUnclosedParagraph.javadoc"));
   }
 
   @Test
-  public void unclosedParagraphFollowedByJavadocTag() throws Exception {
+  void unclosedParagraphFollowedByJavadocTag() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedUnclosedParagraphFollowedByJavadocTagAst.txt"),
         getHtmlPath("InputUnclosedParagraphFollowedByJavadocTag.javadoc"));
   }
 
   @Test
-  public void allJavadocInlineTags() throws Exception {
+  void allJavadocInlineTags() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedAllJavadocInlineTagsAst.txt"),
         getDocPath("InputAllJavadocInlineTags.javadoc"));
   }
 
   @Test
-  public void docRootInheritDoc() throws Exception {
+  void docRootInheritDoc() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedDocRootInheritDocAst.txt"),
         getDocPath("InputDocRootInheritDoc.javadoc"));
   }
 
   @Test
-  public void fewWhiteSpacesAsSeparator() throws Exception {
+  void fewWhiteSpacesAsSeparator() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedFewWhiteSpacesAsSeparatorAst.txt"),
         getDocPath("InputFewWhiteSpacesAsSeparator.javadoc"));
   }
 
   @Test
-  public void mixedCaseOfHtmlTags() throws Exception {
+  void mixedCaseOfHtmlTags() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedMixedCaseOfHtmlTagsAst.txt"),
         getHtmlPath("InputMixedCaseOfHtmlTags.javadoc"));
   }
 
   @Test
-  public void htmlComments() throws Exception {
+  void htmlComments() throws Exception {
     verifyJavadocTree(getHtmlPath("expectedCommentsAst.txt"), getHtmlPath("InputComments.javadoc"));
   }
 
   @Test
-  public void negativeNumberInAttribute() throws Exception {
+  void negativeNumberInAttribute() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedNegativeNumberInAttributeAst.txt"),
         getHtmlPath("InputNegativeNumberInAttribute.javadoc"));
   }
 
   @Test
-  public void dollarInLink() throws Exception {
+  void dollarInLink() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedDollarInLinkAst.txt"), getDocPath("InputDollarInLink.javadoc"));
   }
 
   @Test
-  public void dotCharacterInCustomTags() throws Exception {
+  void dotCharacterInCustomTags() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedCustomTagWithDotAst.txt"), getDocPath("InputCustomTagWithDot.javadoc"));
   }
 
   @Test
-  public void testLinkToPackage() throws Exception {
+  void linkToPackage() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedLinkToPackageAst.txt"), getDocPath("InputLinkToPackage.javadoc"));
   }
 
   @Test
-  public void testLeadingAsterisksExtended() throws Exception {
+  void leadingAsterisksExtended() throws Exception {
     verifyJavadocTree(
         getPath("expectedLeadingAsterisksExtendedAst.txt"),
         getPath("InputLeadingAsterisksExtended.javadoc"));
   }
 
   @Test
-  public void testInlineCustomJavadocTag() throws Exception {
+  void inlineCustomJavadocTag() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedInlineCustomJavadocTagAst.txt"),
         getDocPath("InputInlineCustomJavadocTag.javadoc"));
   }
 
   @Test
-  public void testAttributeValueWithoutQuotes() throws Exception {
+  void attributeValueWithoutQuotes() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedAttributeValueWithoutQuotesAst.txt"),
         getHtmlPath("InputAttributeValueWithoutQuotes.javadoc"));
   }
 
   @Test
-  public void testClosedOtherTag() throws Exception {
+  void closedOtherTag() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedClosedOtherTagAst.txt"), getHtmlPath("InputClosedOtherTag.javadoc"));
   }
 
   @Test
-  public void testAllStandardJavadocTags() throws Exception {
+  void allStandardJavadocTags() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedAllStandardJavadocTagsAst.txt"),
         getDocPath("InputAllStandardJavadocTags.javadoc"));
   }
 
   @Test
-  public void testAsteriskInJavadocInlineTag() throws Exception {
+  void asteriskInJavadocInlineTag() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedAsteriskInJavadocInlineTagAst.txt"),
         getDocPath("InputAsteriskInJavadocInlineTag.javadoc"));
   }
 
   @Test
-  public void testAsteriskInLiteral() throws Exception {
+  void asteriskInLiteral() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedAsteriskInLiteralAst.txt"),
         getDocPath("InputAsteriskInLiteral.javadoc"));
   }
 
   @Test
-  public void testInnerBracesInCodeTag() throws Exception {
+  void innerBracesInCodeTag() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedInnerBracesInCodeTagAst.txt"),
         getDocPath("InputInnerBracesInCodeTag.javadoc"));
   }
 
   @Test
-  public void testNewlineAndAsteriskInParameters() throws Exception {
+  void newlineAndAsteriskInParameters() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedNewlineAndAsteriskInParametersAst.txt"),
         getDocPath("InputNewlineAndAsteriskInParameters.javadoc"));
   }
 
   @Test
-  public void testTwoLinkTagsInRow() throws Exception {
+  void twoLinkTagsInRow() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedTwoLinkTagsInRowAst.txt"), getDocPath("InputTwoLinkTagsInRow.javadoc"));
   }
 
   @Test
-  public void testJavadocWithCrAsNewline() throws Exception {
+  void javadocWithCrAsNewline() throws Exception {
     verifyJavadocTree(
         getPath("expectedJavadocWithCrAsNewlineAst.txt"),
         getPath("InputJavadocWithCrAsNewline.javadoc"));
   }
 
   @Test
-  public void testNestingWithSingletonElement() throws Exception {
+  void nestingWithSingletonElement() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedNestingWithSingletonElementAst.txt"),
         getHtmlPath("InputNestingWithSingletonElement.javadoc"));
   }
 
   @Test
-  public void testVoidElements() throws Exception {
+  void voidElements() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedVoidElementsAst.txt"), getHtmlPath("InputVoidElements.javadoc"));
   }
 
   @Test
-  public void testHtmlVoidElementEmbed() throws Exception {
+  void htmlVoidElementEmbed() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedHtmlVoidElementEmbedAst.txt"),
         getHtmlPath("InputHtmlVoidElementEmbed.javadoc"));
   }
 
   @Test
-  public void testSpaceBeforeDescriptionInBlockJavadocTags() throws Exception {
+  void spaceBeforeDescriptionInBlockJavadocTags() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedSpaceBeforeDescriptionInBlockJavadocTagsAst.txt"),
         getDocPath("InputSpaceBeforeDescriptionInBlockJavadocTags.javadoc"));
   }
 
   @Test
-  public void testEmptyDescriptionBeforeTags() throws Exception {
+  void emptyDescriptionBeforeTags() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedEmptyDescriptionBeforeTags.txt"),
         getDocPath("InputEmptyDescriptionBeforeTags.javadoc"));
   }
 
   @Test
-  public void testSpaceBeforeDescriptionInInlineTags() throws Exception {
+  void spaceBeforeDescriptionInInlineTags() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedSpaceBeforeArgsInInlineTagsAst.txt"),
         getDocPath("InputSpaceBeforeArgsInInlineTags.javadoc"));
   }
 
   @Test
-  public void testHtmlVoidElementKeygen() throws Exception {
+  void htmlVoidElementKeygen() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedHtmlVoidElementKeygenAst.txt"),
         getHtmlPath("InputHtmlVoidElementKeygen.javadoc"));
   }
 
   @Test
-  public void testHtmlVoidElementSource() throws Exception {
+  void htmlVoidElementSource() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedHtmlVoidElementSourceAst.txt"),
         getHtmlPath("InputHtmlVoidElementSource.javadoc"));
   }
 
   @Test
-  public void testHtmlVoidElementTrack() throws Exception {
+  void htmlVoidElementTrack() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedHtmlVoidElementTrackAst.txt"),
         getHtmlPath("InputHtmlVoidElementTrack.javadoc"));
   }
 
   @Test
-  public void testHtmlVoidElementWbr() throws Exception {
+  void htmlVoidElementWbr() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedHtmlVoidElementWbrAst.txt"),
         getHtmlPath("InputHtmlVoidElementWbr.javadoc"));
   }
 
   @Test
-  public void testOptgroupHtmlTag() throws Exception {
+  void optgroupHtmlTag() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedOptgroupHtmlTagAst.txt"), getHtmlPath("InputOptgroupHtmlTag.javadoc"));
   }
 
   @Test
-  public void testNonTightOptgroupHtmlTag() throws Exception {
+  void nonTightOptgroupHtmlTag() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedNonTightOptgroupHtmlTagAst.txt"),
         getHtmlPath("InputNonTightOptgroupHtmlTag.javadoc"));
   }
 
   @Test
-  public void testRbHtmlTag() throws Exception {
+  void rbHtmlTag() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedRbHtmlTagAst.txt"), getHtmlPath("InputRbHtmlTag.javadoc"));
   }
 
   @Test
-  public void testNonTightRbHtmlTag() throws Exception {
+  void nonTightRbHtmlTag() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedNonTightRbHtmlTagAst.txt"),
         getHtmlPath("InputNonTightRbHtmlTag.javadoc"));
   }
 
   @Test
-  public void testRtHtmlTag() throws Exception {
+  void rtHtmlTag() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedRtHtmlTagAst.txt"), getHtmlPath("InputRtHtmlTag.javadoc"));
   }
 
   @Test
-  public void testNonTightRtHtmlTag() throws Exception {
+  void nonTightRtHtmlTag() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedNonTightRtHtmlTagAst.txt"),
         getHtmlPath("InputNonTightRtHtmlTag.javadoc"));
   }
 
   @Test
-  public void testRtcHtmlTag() throws Exception {
+  void rtcHtmlTag() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedRtcHtmlTagAst.txt"), getHtmlPath("InputRtcHtmlTag.javadoc"));
   }
 
   @Test
-  public void testNonTightRtcHtmlTag() throws Exception {
+  void nonTightRtcHtmlTag() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedNonTightRtcHtmlTagAst.txt"),
         getHtmlPath("InputNonTightRtcHtmlTag.javadoc"));
   }
 
   @Test
-  public void testRpHtmlTag() throws Exception {
+  void rpHtmlTag() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedRpHtmlTagAst.txt"), getHtmlPath("InputRpHtmlTag.javadoc"));
   }
 
   @Test
-  public void testNonTightRpHtmlTag() throws Exception {
+  void nonTightRpHtmlTag() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedNonTightRpHtmlTagAst.txt"),
         getHtmlPath("InputNonTightRpHtmlTag.javadoc"));
   }
 
   @Test
-  public void testLeadingAsteriskAfterSeeTag() throws Exception {
+  void leadingAsteriskAfterSeeTag() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedLeadingAsteriskAfterSeeTagAst.txt"),
         getDocPath("InputLeadingAsteriskAfterSeeTag.javadoc"));
   }
 
   @Test
-  public void testUppercaseInPackageName() throws Exception {
+  void uppercaseInPackageName() throws Exception {
     verifyJavadocTree(
         getDocPath("expectedUppercaseInPackageNameAst.txt"),
         getDocPath("InputUppercaseInPackageName.javadoc"));
   }
 
   @Test
-  public void testParagraph() throws Exception {
+  void paragraph() throws Exception {
     verifyJavadocTree(
         getHtmlPath("expectedParagraphAst.txt"), getHtmlPath("InputParagraph.javadoc"));
   }
 
   @Test
-  public void testCdata() throws Exception {
+  void cdata() throws Exception {
     verifyJavadocTree(getHtmlPath("expectedCdataAst.txt"), getHtmlPath("InputCdata.javadoc"));
   }
 
   @Test
-  public void testCrAsNewlineMultiline() throws Exception {
+  void crAsNewlineMultiline() throws Exception {
     verifyJavadocTree(
         getPath("expectedCrAsNewlineMultiline.txt"), getPath("InputCrAsNewlineMultiline.javadoc"));
   }
 
   @Test
-  public void testDosLineEndingAsNewlineMultiline() throws Exception {
+  void dosLineEndingAsNewlineMultiline() throws Exception {
     verifyJavadocTree(
         getPath("expectedDosLineEndingAsNewlineMultiline.txt"),
         getPath("InputDosLineEndingAsNewlineMultiline.javadoc"));
--- a/src/test/java/com/puppycrawl/tools/checkstyle/gui/BaseCellEditorTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/gui/BaseCellEditorTest.java
@@ -25,10 +25,10 @@ import javax.swing.event.CellEditorListener;
 import javax.swing.event.ChangeEvent;
 import org.junit.jupiter.api.Test;
 
-class BaseCellEditorTest {
+final class BaseCellEditorTest {
 
   @Test
-  public void testToString() {
+  void testToString() {
 
     final BaseCellEditor cellEditor = new BaseCellEditor();
 
@@ -36,7 +36,7 @@ class BaseCellEditorTest {
   }
 
   @Test
-  public void testStopCellEditing() {
+  void stopCellEditing() {
 
     final BaseCellEditor cellEditor = new BaseCellEditor();
 
@@ -44,7 +44,7 @@ class BaseCellEditorTest {
   }
 
   @Test
-  public void testFireEditingStoppedAndCanceled() {
+  void fireEditingStoppedAndCanceled() {
 
     final BaseCellEditor cellEditor = new BaseCellEditor();
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/gui/CodeSelectorPresentationTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/gui/CodeSelectorPresentationTest.java
@@ -32,7 +32,7 @@ import java.util.List;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-public class CodeSelectorPresentationTest extends AbstractPathTestSupport {
+final class CodeSelectorPresentationTest extends AbstractPathTestSupport {
 
   private MainFrameModel model;
 
@@ -41,7 +41,7 @@ public class CodeSelectorPresentationTest extends AbstractPathTestSupport {
   private ImmutableList<Integer> linesToPosition;
 
   @BeforeEach
-  public void loadFile() throws Exception {
+  void loadFile() throws Exception {
     model = new MainFrameModel();
     model.setParseMode(ParseMode.JAVA_WITH_JAVADOC_AND_COMMENTS);
     model.openFile(new File(getPath("InputCodeSelectorPresentation.java")));
@@ -73,7 +73,7 @@ public class CodeSelectorPresentationTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testDetailASTSelection() {
+  void detailASTSelection() {
     final CodeSelectorPresentation selector = new CodeSelectorPresentation(tree, linesToPosition);
     selector.findSelectionPositions();
     assertWithMessage("Invalid selection start").that(selector.getSelectionStart()).isEqualTo(94);
@@ -81,7 +81,7 @@ public class CodeSelectorPresentationTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testDetailASTLeafSelection() {
+  void detailASTLeafSelection() {
     final DetailAST leaf = tree.getLastChild().getFirstChild();
     final CodeSelectorPresentation selector = new CodeSelectorPresentation(leaf, linesToPosition);
     selector.findSelectionPositions();
@@ -90,7 +90,7 @@ public class CodeSelectorPresentationTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testDetailASTNoSelection() {
+  void detailASTNoSelection() {
     final DetailAST leaf = tree.getFirstChild();
     final CodeSelectorPresentation selector = new CodeSelectorPresentation(leaf, linesToPosition);
     selector.findSelectionPositions();
@@ -99,7 +99,7 @@ public class CodeSelectorPresentationTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testDetailNodeSelection() {
+  void detailNodeSelection() {
     final DetailNode javadoc =
         (DetailNode)
             model
@@ -113,7 +113,7 @@ public class CodeSelectorPresentationTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testDetailNodeLeafSelection() {
+  void detailNodeLeafSelection() {
     final DetailNode javadoc =
         (DetailNode)
             model
--- a/src/test/java/com/puppycrawl/tools/checkstyle/gui/MainFrameModelTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/gui/MainFrameModelTest.java
@@ -33,7 +33,7 @@ import java.util.Locale;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-public class MainFrameModelTest extends AbstractModuleTestSupport {
+final class MainFrameModelTest extends AbstractModuleTestSupport {
 
   private static final String FILE_NAME_TEST_DATA = "InputMainFrameModel.java";
   private static final String FILE_NAME_NON_EXISTENT = "non-existent.file";
@@ -49,13 +49,13 @@ public class MainFrameModelTest extends AbstractModuleTestSupport {
   }
 
   @BeforeEach
-  public void prepareTestData() throws IOException {
+  void prepareTestData() throws IOException {
     model = new MainFrameModel();
     testData = new File(getPath(FILE_NAME_TEST_DATA));
   }
 
   @Test
-  public void testParseModeEnum() {
+  void parseModeEnum() {
     for (final ParseMode parseMode : ParseMode.values()) {
       switch (parseMode) {
         case PLAIN_JAVA:
@@ -80,7 +80,7 @@ public class MainFrameModelTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOpenFileWithParseModePlainJava() throws Exception {
+  void openFileWithParseModePlainJava() throws Exception {
     // Default parse mode: Plain Java
     model.openFile(testData);
     verifyCorrectTestDataInFrameModel();
@@ -90,7 +90,7 @@ public class MainFrameModelTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOpenFileWithParseModeJavaWithComments() throws Exception {
+  void openFileWithParseModeJavaWithComments() throws Exception {
     model.setParseMode(ParseMode.JAVA_WITH_COMMENTS);
     model.openFile(testData);
 
@@ -98,7 +98,7 @@ public class MainFrameModelTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOpenFileWithParseModeJavaWithJavadocAndComments() throws Exception {
+  void openFileWithParseModeJavaWithJavadocAndComments() throws Exception {
     model.setParseMode(ParseMode.JAVA_WITH_JAVADOC_AND_COMMENTS);
     model.openFile(testData);
 
@@ -106,7 +106,7 @@ public class MainFrameModelTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOpenFileNullParameter() throws Exception {
+  void openFileNullParameter() throws Exception {
     model.openFile(testData);
 
     model.openFile(null);
@@ -116,7 +116,7 @@ public class MainFrameModelTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOpenFileNullParameter2() throws Exception {
+  void openFileNullParameter2() throws Exception {
     model.openFile(null);
 
     assertWithMessage("Test is null").that(model.getText()).isNull();
@@ -128,7 +128,7 @@ public class MainFrameModelTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOpenFileNonExistentFile() throws IOException {
+  void openFileNonExistentFile() throws IOException {
     final File nonExistentFile = new File(getPath(FILE_NAME_NON_EXISTENT));
 
     try {
@@ -147,7 +147,7 @@ public class MainFrameModelTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOpenFileNonCompilableFile() throws IOException {
+  void openFileNonCompilableFile() throws IOException {
     final File nonCompilableFile = new File(getNonCompilablePath(FILE_NAME_NON_COMPILABLE));
 
     try {
@@ -196,7 +196,7 @@ public class MainFrameModelTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testShouldAcceptDirectory() {
+  void shouldAcceptDirectory() {
     final File directory = mock();
     when(directory.isDirectory()).thenReturn(true);
     assertWithMessage("MainFrame should accept directory")
@@ -205,7 +205,7 @@ public class MainFrameModelTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testShouldAcceptFile() throws IOException {
+  void shouldAcceptFile() throws IOException {
     final File javaFile = new File(getPath(FILE_NAME_TEST_DATA));
     assertWithMessage("MainFrame should accept java file")
         .that(MainFrameModel.shouldAcceptFile(javaFile))
@@ -213,7 +213,7 @@ public class MainFrameModelTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testShouldNotAcceptNonJavaFile() {
+  void shouldNotAcceptNonJavaFile() {
     final File nonJavaFile = mock();
     when(nonJavaFile.isDirectory()).thenReturn(false);
     when(nonJavaFile.getName()).thenReturn(FILE_NAME_NON_JAVA);
@@ -223,7 +223,7 @@ public class MainFrameModelTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testShouldNotAcceptNonExistentFile() throws IOException {
+  void shouldNotAcceptNonExistentFile() throws IOException {
     final File nonExistentFile = new File(getPath(FILE_NAME_NON_EXISTENT));
     assertWithMessage("MainFrame should not accept non-existent file")
         .that(MainFrameModel.shouldAcceptFile(nonExistentFile))
@@ -231,7 +231,7 @@ public class MainFrameModelTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOpenFileForUnknownParseMode() throws IOException {
+  void openFileForUnknownParseMode() throws IOException {
     final File javaFile = new File(getPath(FILE_NAME_TEST_DATA));
     final ParseMode mock = mock();
     model.setParseMode(mock);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/gui/MainFrameTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/gui/MainFrameTest.java
@@ -46,7 +46,7 @@ import org.junit.jupiter.api.Test;
 import org.mockito.MockedConstruction;
 import org.mockito.MockedStatic;
 
-public class MainFrameTest extends AbstractGuiTestSupport {
+final class MainFrameTest extends AbstractGuiTestSupport {
 
   private static final String TEST_FILE_NAME = "InputMainFrame.java";
   private static final String NON_EXISTENT_FILE_NAME = "non-existent.file";
@@ -59,17 +59,17 @@ public class MainFrameTest extends AbstractGuiTestSupport {
   }
 
   @BeforeEach
-  public void prepare() {
+  void prepare() {
     mainFrame = new MainFrame();
   }
 
   @AfterEach
-  public void tearDown() {
+  void tearDown() {
     Arrays.stream(mainFrame.getOwnedWindows()).forEach(Window::dispose);
   }
 
   @Test
-  public void testOpenFile() throws IOException {
+  void openFile() throws IOException {
     mainFrame.openFile(new File(getPath(TEST_FILE_NAME)));
     assertWithMessage("Unexpected frame title")
         .that(mainFrame.getTitle())
@@ -83,7 +83,7 @@ public class MainFrameTest extends AbstractGuiTestSupport {
    * @throws IOException if I/O exception occurs while forming the path.
    */
   @Test
-  public void testOpenNonExistentFile() throws IOException {
+  void openNonExistentFile() throws IOException {
     final File file = new File(getPath(NON_EXISTENT_FILE_NAME));
     try (MockedStatic<JOptionPane> optionPane = mockStatic(JOptionPane.class)) {
       mainFrame.openFile(file);
@@ -99,7 +99,7 @@ public class MainFrameTest extends AbstractGuiTestSupport {
   }
 
   @Test
-  public void testChangeMode() {
+  void changeMode() {
     final JComboBox<MainFrameModel.ParseMode> modesCombobox =
         findComponentByName(mainFrame, "modesCombobox");
     modesCombobox.setSelectedIndex(MainFrameModel.ParseMode.JAVA_WITH_COMMENTS.ordinal());
@@ -117,7 +117,7 @@ public class MainFrameTest extends AbstractGuiTestSupport {
    * @throws IOException if I/O exception occurs while forming the path.
    */
   @Test
-  public void testOpenFileButton() throws IOException {
+  void openFileButton() throws IOException {
     final JButton openFileButton = findComponentByName(mainFrame, "openFileButton");
     final File testFile = new File(getPath(TEST_FILE_NAME));
     try (MockedConstruction<JFileChooser> mocked =
@@ -139,7 +139,7 @@ public class MainFrameTest extends AbstractGuiTestSupport {
    * JFileChooser} is mocked to obtain an instance of {@code JavaFileFilter} class.
    */
   @Test
-  public void testFileFilter() {
+  void fileFilter() {
     final JButton openFileButton = findComponentByName(mainFrame, "openFileButton");
     try (MockedConstruction<JFileChooser> mocked =
         mockConstruction(
@@ -162,7 +162,7 @@ public class MainFrameTest extends AbstractGuiTestSupport {
   }
 
   @Test
-  public void testExpandButton() {
+  void expandButton() {
     final JButton expandButton = findComponentByName(mainFrame, "expandButton");
     final JTextArea xpathTextArea = findComponentByName(mainFrame, "xpathTextArea");
     expandButton.doClick();
@@ -176,7 +176,7 @@ public class MainFrameTest extends AbstractGuiTestSupport {
   }
 
   @Test
-  public void testFindNodeButton() throws IOException {
+  void findNodeButton() throws IOException {
     mainFrame.openFile(new File(getPath(TEST_FILE_NAME)));
     final JButton findNodeButton = findComponentByName(mainFrame, "findNodeButton");
     final JTextArea xpathTextArea = findComponentByName(mainFrame, "xpathTextArea");
--- a/src/test/java/com/puppycrawl/tools/checkstyle/gui/MainTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/gui/MainTest.java
@@ -28,7 +28,7 @@ import javax.swing.SwingUtilities;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ValueSource;
 
-public class MainTest extends AbstractGuiTestSupport {
+final class MainTest extends AbstractGuiTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -43,7 +43,7 @@ public class MainTest extends AbstractGuiTestSupport {
    */
   @ParameterizedTest
   @ValueSource(strings = {";", "InputMain.java"})
-  public void testMain(String argList) throws Exception {
+  void main(String argList) throws Exception {
     final String[] args = argList.split(";");
     for (int i = 0; i < args.length; i++) {
       args[i] = getPath(args[i]);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/gui/ParseTreeTableModelTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/gui/ParseTreeTableModelTest.java
@@ -38,7 +38,7 @@ import java.io.File;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-public class ParseTreeTableModelTest extends AbstractPathTestSupport {
+final class ParseTreeTableModelTest extends AbstractPathTestSupport {
 
   private DetailAST classDef;
 
@@ -48,7 +48,7 @@ public class ParseTreeTableModelTest extends AbstractPathTestSupport {
   }
 
   @BeforeEach
-  public void loadTree() throws Exception {
+  void loadTree() throws Exception {
     classDef =
         JavaParser.parseFile(
                 new File(getPath("InputParseTreeTablePresentation.java")),
@@ -57,13 +57,13 @@ public class ParseTreeTableModelTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testChildCount() {
+  void childCount() {
     final int childCount = new ParseTreeTableModel(null).getChildCount(classDef);
     assertWithMessage("Invalid child count").that(childCount).isEqualTo(5);
   }
 
   @Test
-  public void testChild() {
+  void child() {
     final Object child = new ParseTreeTableModel(null).getChild(classDef, 1);
     assertWithMessage("Invalid child type").that(child).isInstanceOf(DetailAST.class);
     final int type = ((DetailAST) child).getType();
@@ -71,7 +71,7 @@ public class ParseTreeTableModelTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testCommentChildCount() {
+  void commentChildCount() {
     final DetailAST commentContentNode =
         classDef.findFirstToken(BLOCK_COMMENT_BEGIN).findFirstToken(COMMENT_CONTENT);
     final ParseTreeTableModel parseTree = new ParseTreeTableModel(null);
@@ -81,7 +81,7 @@ public class ParseTreeTableModelTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testChildCountInJavaAndJavadocMode() {
+  void childCountInJavaAndJavadocMode() {
     final ParseTreeTableModel parseTree = new ParseTreeTableModel(null);
     parseTree.setParseMode(ParseMode.JAVA_WITH_JAVADOC_AND_COMMENTS);
     final int childCount = parseTree.getChildCount(classDef);
@@ -89,7 +89,7 @@ public class ParseTreeTableModelTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testChildInJavaAndJavadocMode() {
+  void childInJavaAndJavadocMode() {
     final ParseTreeTableModel parseTree = new ParseTreeTableModel(null);
     parseTree.setParseMode(ParseMode.JAVA_WITH_JAVADOC_AND_COMMENTS);
     final Object child = parseTree.getChild(classDef, 1);
@@ -99,7 +99,7 @@ public class ParseTreeTableModelTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testCommentChildCountInJavaAndJavadocMode() {
+  void commentChildCountInJavaAndJavadocMode() {
     final DetailAST commentContentNode =
         classDef.findFirstToken(BLOCK_COMMENT_BEGIN).findFirstToken(COMMENT_CONTENT);
     final ParseTreeTableModel parseTree = new ParseTreeTableModel(null);
@@ -109,7 +109,7 @@ public class ParseTreeTableModelTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testCommentChildInJavaAndJavadocMode() {
+  void commentChildInJavaAndJavadocMode() {
     final DetailAST commentContentNode =
         classDef.findFirstToken(BLOCK_COMMENT_BEGIN).findFirstToken(COMMENT_CONTENT);
     final ParseTreeTableModel parseTree = new ParseTreeTableModel(null);
@@ -119,7 +119,7 @@ public class ParseTreeTableModelTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testJavadocCommentChildCount() {
+  void javadocCommentChildCount() {
     final DetailAST commentContentNode =
         classDef.findFirstToken(BLOCK_COMMENT_BEGIN).findFirstToken(COMMENT_CONTENT);
     final ParseTreeTableModel parseTree = new ParseTreeTableModel(null);
@@ -131,7 +131,7 @@ public class ParseTreeTableModelTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testJavadocCommentChild() {
+  void javadocCommentChild() {
     final DetailAST commentContentNode =
         classDef.findFirstToken(BLOCK_COMMENT_BEGIN).findFirstToken(COMMENT_CONTENT);
     final ParseTreeTableModel parseTree = new ParseTreeTableModel(null);
@@ -149,7 +149,7 @@ public class ParseTreeTableModelTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testJavadocChildCount() {
+  void javadocChildCount() {
     final DetailAST commentContentNode =
         classDef.findFirstToken(BLOCK_COMMENT_BEGIN).findFirstToken(COMMENT_CONTENT);
     final ParseTreeTableModel parseTree = new ParseTreeTableModel(null);
@@ -163,7 +163,7 @@ public class ParseTreeTableModelTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testJavadocChild() {
+  void javadocChild() {
     final DetailAST commentContentNode =
         classDef.findFirstToken(BLOCK_COMMENT_BEGIN).findFirstToken(COMMENT_CONTENT);
     final ParseTreeTableModel parseTree = new ParseTreeTableModel(null);
@@ -179,7 +179,7 @@ public class ParseTreeTableModelTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetIndexOfChild() {
+  void getIndexOfChild() {
     DetailAST child = classDef.findFirstToken(MODIFIERS);
     assertWithMessage("Child must not be null").that(child).isNotNull();
     final ParseTreeTableModel parseTree = new ParseTreeTableModel(null);
@@ -195,7 +195,7 @@ public class ParseTreeTableModelTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetValueAt() {
+  void getValueAt() {
     final DetailAST classIdentNode = classDef.findFirstToken(IDENT);
     assertWithMessage("Expected a non-null identifier classDef here")
         .that(classIdentNode)
@@ -223,7 +223,7 @@ public class ParseTreeTableModelTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetValueAtDetailNode() {
+  void getValueAtDetailNode() {
     final DetailAST commentContentNode =
         classDef.findFirstToken(BLOCK_COMMENT_BEGIN).findFirstToken(COMMENT_CONTENT);
     assertWithMessage("Comment classDef cannot be null").that(commentContentNode).isNotNull();
@@ -258,7 +258,7 @@ public class ParseTreeTableModelTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testColumnMethods() {
+  void columnMethods() {
     final ParseTreeTableModel parseTree = new ParseTreeTableModel(null);
     assertWithMessage("Invalid type")
         .that(parseTree.getColumnClass(0))
@@ -279,7 +279,7 @@ public class ParseTreeTableModelTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testColumnNames() {
+  void columnNames() {
     final ParseTreeTableModel parseTree = new ParseTreeTableModel(null);
     assertWithMessage("Invalid column count").that(parseTree.getColumnCount()).isEqualTo(5);
     assertWithMessage("Invalid column name").that(parseTree.getColumnName(0)).isEqualTo("Tree");
--- a/src/test/java/com/puppycrawl/tools/checkstyle/gui/ParseTreeTablePresentationTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/gui/ParseTreeTablePresentationTest.java
@@ -34,7 +34,7 @@ import java.io.File;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-public class ParseTreeTablePresentationTest extends AbstractPathTestSupport {
+final class ParseTreeTablePresentationTest extends AbstractPathTestSupport {
 
   private DetailAST tree;
 
@@ -44,7 +44,7 @@ public class ParseTreeTablePresentationTest extends AbstractPathTestSupport {
   }
 
   @BeforeEach
-  public void loadTree() throws Exception {
+  void loadTree() throws Exception {
     tree =
         JavaParser.parseFile(
                 new File(getPath("InputParseTreeTablePresentation.java")),
@@ -54,7 +54,7 @@ public class ParseTreeTablePresentationTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testRoot() throws Exception {
+  void root() throws Exception {
     final DetailAST root =
         JavaParser.parseFile(
             new File(getPath("InputParseTreeTablePresentation.java")),
@@ -63,13 +63,13 @@ public class ParseTreeTablePresentationTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testChildCount() {
+  void childCount() {
     final int childCount = new ParseTreeTablePresentation(null).getChildCount(tree);
     assertWithMessage("Invalid child count").that(childCount).isEqualTo(5);
   }
 
   @Test
-  public void testChildCountInJavaAndJavadocMode() {
+  void childCountInJavaAndJavadocMode() {
     final ParseTreeTablePresentation parseTree = new ParseTreeTablePresentation(null);
     parseTree.setParseMode(ParseMode.JAVA_WITH_JAVADOC_AND_COMMENTS);
     final int childCount = parseTree.getChildCount(tree);
@@ -77,7 +77,7 @@ public class ParseTreeTablePresentationTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testChild() {
+  void child() {
     final Object child = new ParseTreeTablePresentation(null).getChild(tree, 1);
     assertWithMessage("Invalid child type").that(child).isInstanceOf(DetailAST.class);
     final int type = ((DetailAST) child).getType();
@@ -87,7 +87,7 @@ public class ParseTreeTablePresentationTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testChildInJavaAndJavadocMode() {
+  void childInJavaAndJavadocMode() {
     final ParseTreeTablePresentation parseTree = new ParseTreeTablePresentation(null);
     parseTree.setParseMode(ParseMode.JAVA_WITH_JAVADOC_AND_COMMENTS);
     final Object child = parseTree.getChild(tree, 1);
@@ -99,7 +99,7 @@ public class ParseTreeTablePresentationTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testCommentChildCount() {
+  void commentChildCount() {
     final DetailAST commentContentNode = tree.getFirstChild().getNextSibling().getFirstChild();
     final ParseTreeTablePresentation parseTree = new ParseTreeTablePresentation(null);
     parseTree.setParseMode(ParseMode.JAVA_WITH_COMMENTS);
@@ -108,7 +108,7 @@ public class ParseTreeTablePresentationTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testCommentChildCountInJavaAndJavadocMode() {
+  void commentChildCountInJavaAndJavadocMode() {
     final ParseTreeTablePresentation parseTree = new ParseTreeTablePresentation(null);
     parseTree.setParseMode(ParseMode.JAVA_WITH_JAVADOC_AND_COMMENTS);
     final DetailAST commentContentNode =
@@ -123,7 +123,7 @@ public class ParseTreeTablePresentationTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testCommentChildInJavaAndJavadocMode() {
+  void commentChildInJavaAndJavadocMode() {
     final ParseTreeTablePresentation parseTree = new ParseTreeTablePresentation(null);
     parseTree.setParseMode(ParseMode.JAVA_WITH_JAVADOC_AND_COMMENTS);
     final DetailAST commentContentNode =
@@ -138,7 +138,7 @@ public class ParseTreeTablePresentationTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testJavadocCommentChildCount() {
+  void javadocCommentChildCount() {
     final DetailAST commentContentNode = tree.getFirstChild().getNextSibling().getFirstChild();
     final ParseTreeTablePresentation parseTree = new ParseTreeTablePresentation(null);
     final int commentChildCount = parseTree.getChildCount(commentContentNode);
@@ -149,7 +149,7 @@ public class ParseTreeTablePresentationTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testJavadocCommentChild() {
+  void javadocCommentChild() {
     final DetailAST commentContentNode = tree.getFirstChild().getNextSibling().getFirstChild();
     final ParseTreeTablePresentation parseTree = new ParseTreeTablePresentation(null);
     parseTree.setParseMode(ParseMode.JAVA_WITH_JAVADOC_AND_COMMENTS);
@@ -167,7 +167,7 @@ public class ParseTreeTablePresentationTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testJavadocChildCount() {
+  void javadocChildCount() {
     final DetailAST commentContentNode = tree.getFirstChild().getNextSibling().getFirstChild();
     final ParseTreeTablePresentation parseTree = new ParseTreeTablePresentation(null);
     parseTree.setParseMode(ParseMode.JAVA_WITH_JAVADOC_AND_COMMENTS);
@@ -180,7 +180,7 @@ public class ParseTreeTablePresentationTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testJavadocChild() {
+  void javadocChild() {
     final DetailAST commentContentNode = tree.getFirstChild().getNextSibling().getFirstChild();
     final ParseTreeTablePresentation parseTree = new ParseTreeTablePresentation(null);
     parseTree.setParseMode(ParseMode.JAVA_WITH_JAVADOC_AND_COMMENTS);
@@ -195,7 +195,7 @@ public class ParseTreeTablePresentationTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetIndexOfChild() {
+  void getIndexOfChild() {
     DetailAST ithChild = tree.getFirstChild();
     assertWithMessage("Child must not be null").that(ithChild).isNotNull();
     final ParseTreeTablePresentation parseTree = new ParseTreeTablePresentation(null);
@@ -225,7 +225,7 @@ public class ParseTreeTablePresentationTest extends AbstractPathTestSupport {
    *  </pre>
    */
   @Test
-  public void testGetValueAt() {
+  void getValueAt() {
     final DetailAST node = tree.getFirstChild().getNextSibling().getNextSibling().getNextSibling();
 
     assertWithMessage("Expected a non-null identifier node here").that(node).isNotNull();
@@ -253,7 +253,7 @@ public class ParseTreeTablePresentationTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetValueAtDetailNode() {
+  void getValueAtDetailNode() {
     final DetailAST commentContentNode = tree.getFirstChild().getNextSibling().getFirstChild();
     assertWithMessage("Comment node cannot be null").that(commentContentNode).isNotNull();
     final int nodeType = commentContentNode.getType();
@@ -292,7 +292,7 @@ public class ParseTreeTablePresentationTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testColumnMethods() {
+  void columnMethods() {
     final ParseTreeTablePresentation parseTree = new ParseTreeTablePresentation(null);
     assertWithMessage("Invalid type")
         .that(parseTree.getColumnClass(0))
@@ -313,7 +313,7 @@ public class ParseTreeTablePresentationTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testColumnNames() {
+  void columnNames() {
     final ParseTreeTablePresentation parseTree = new ParseTreeTablePresentation(null);
     assertWithMessage("Invalid column count").that(parseTree.getColumnCount()).isEqualTo(5);
     assertWithMessage("Invalid column name").that(parseTree.getColumnName(0)).isEqualTo("Tree");
--- a/src/test/java/com/puppycrawl/tools/checkstyle/gui/TreeTableTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/gui/TreeTableTest.java
@@ -35,7 +35,7 @@ import javax.swing.tree.TreePath;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-public class TreeTableTest extends AbstractGuiTestSupport {
+final class TreeTableTest extends AbstractGuiTestSupport {
 
   private static final String TEST_FILE_NAME = "InputTreeTable.java";
 
@@ -47,7 +47,7 @@ public class TreeTableTest extends AbstractGuiTestSupport {
   }
 
   @BeforeEach
-  public void prepare() throws Exception {
+  void prepare() throws Exception {
     final MainFrameModel model = new MainFrameModel();
     model.openFile(new File(getPath(TEST_FILE_NAME)));
     treeTable = new TreeTable(model.getParseTreeTableModel());
@@ -58,7 +58,7 @@ public class TreeTableTest extends AbstractGuiTestSupport {
   }
 
   @Test
-  public void testExpandOnMouseDoubleClick() {
+  void expandOnMouseDoubleClick() {
     final MouseEvent mouseDoubleClickEvent =
         new MouseEvent(treeTable, MouseEvent.MOUSE_CLICKED, 0, 0, 0, 0, 2, false);
     assertWithMessage("The tree should be initially expanded")
@@ -75,7 +75,7 @@ public class TreeTableTest extends AbstractGuiTestSupport {
   }
 
   @Test
-  public void testNothingChangedOnMouseSingleClick() {
+  void nothingChangedOnMouseSingleClick() {
     final MouseEvent mouseSingleClickEvent =
         new MouseEvent(treeTable, MouseEvent.MOUSE_CLICKED, 0, 0, 0, 0, 1, false);
     assertWithMessage("The tree should be initially expanded")
@@ -88,7 +88,7 @@ public class TreeTableTest extends AbstractGuiTestSupport {
   }
 
   @Test
-  public void testExpandOnEnterKey() {
+  void expandOnEnterKey() {
     final ActionEvent expandCollapseActionEvent =
         new ActionEvent(treeTable, ActionEvent.ACTION_PERFORMED, "expand/collapse");
     final ActionListener actionForEnter =
@@ -107,7 +107,7 @@ public class TreeTableTest extends AbstractGuiTestSupport {
   }
 
   @Test
-  public void testFindNodesAllClassDefs() throws IOException {
+  void findNodesAllClassDefs() throws IOException {
     final MainFrame mainFrame = new MainFrame();
     mainFrame.openFile(new File(getPath("InputTreeTableXpathAreaPanel.java")));
     final JButton findNodeButton = findComponentByName(mainFrame, "findNodeButton");
@@ -128,7 +128,7 @@ public class TreeTableTest extends AbstractGuiTestSupport {
   }
 
   @Test
-  public void testFindNodesIdent() throws IOException {
+  void findNodesIdent() throws IOException {
     final MainFrame mainFrame = new MainFrame();
     mainFrame.openFile(new File(getPath("InputTreeTableXpathAreaPanel.java")));
     final JButton findNodeButton = findComponentByName(mainFrame, "findNodeButton");
@@ -163,7 +163,7 @@ public class TreeTableTest extends AbstractGuiTestSupport {
   }
 
   @Test
-  public void testFindNodesMissingElements() throws IOException {
+  void findNodesMissingElements() throws IOException {
     final MainFrame mainFrame = new MainFrame();
     mainFrame.openFile(new File(getPath("InputTreeTableXpathAreaPanel.java")));
     final JButton findNodeButton = findComponentByName(mainFrame, "findNodeButton");
@@ -179,7 +179,7 @@ public class TreeTableTest extends AbstractGuiTestSupport {
   }
 
   @Test
-  public void testFindNodesUnexpectedTokenAtStart() throws IOException {
+  void findNodesUnexpectedTokenAtStart() throws IOException {
     final MainFrame mainFrame = new MainFrame();
     mainFrame.openFile(new File(getPath("InputTreeTableXpathAreaPanel.java")));
     final JButton findNodeButton = findComponentByName(mainFrame, "findNodeButton");
@@ -195,7 +195,7 @@ public class TreeTableTest extends AbstractGuiTestSupport {
   }
 
   @Test
-  public void testFindNodesInvalidCharacterInExpression() throws IOException {
+  void findNodesInvalidCharacterInExpression() throws IOException {
     final MainFrame mainFrame = new MainFrame();
     mainFrame.openFile(new File(getPath("InputTreeTableXpathAreaPanel.java")));
     final JButton findNodeButton = findComponentByName(mainFrame, "findNodeButton");
@@ -211,7 +211,7 @@ public class TreeTableTest extends AbstractGuiTestSupport {
   }
 
   @Test
-  public void testTreeModelAdapterMethods() throws IOException {
+  void treeModelAdapterMethods() throws IOException {
     final MainFrame mainFrame = new MainFrame();
     mainFrame.openFile(new File(getPath("InputTreeTableXpathAreaPanel.java")));
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/internal/AllChecksTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/internal/AllChecksTest.java
@@ -20,6 +20,7 @@
 package com.puppycrawl.tools.checkstyle.internal;
 
 import static com.google.common.truth.Truth.assertWithMessage;
+import static java.util.stream.Collectors.toUnmodifiableSet;
 
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
@@ -53,11 +54,10 @@ import java.util.Map.Entry;
 import java.util.Properties;
 import java.util.Set;
 import java.util.TreeMap;
-import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import org.junit.jupiter.api.Test;
 
-public class AllChecksTest extends AbstractModuleTestSupport {
+final class AllChecksTest extends AbstractModuleTestSupport {
 
   private static final Locale[] ALL_LOCALES = {
     Locale.CHINESE,
@@ -85,20 +85,20 @@ public class AllChecksTest extends AbstractModuleTestSupport {
         Stream.of(
                 // we use GenericWhitespace for this behavior
                 "GENERIC_START", "GENERIC_END")
-            .collect(Collectors.toUnmodifiableSet()));
+            .collect(toUnmodifiableSet()));
     CHECKSTYLE_TOKENS_IN_CONFIG_TO_IGNORE.put(
         "AbbreviationAsWordInName",
         Stream.of(
                 // enum values should be uppercase, we use EnumValueNameCheck instead
                 "ENUM_CONSTANT_DEF")
-            .collect(Collectors.toUnmodifiableSet()));
+            .collect(toUnmodifiableSet()));
     CHECKSTYLE_TOKENS_IN_CONFIG_TO_IGNORE.put(
         "FinalLocalVariable",
         Stream.of(
                 // we prefer all parameters be effectively final as to not damage readability
                 // we use ParameterAssignmentCheck to enforce this
                 "PARAMETER_DEF")
-            .collect(Collectors.toUnmodifiableSet()));
+            .collect(toUnmodifiableSet()));
     // we have no need to block these specific tokens
     CHECKSTYLE_TOKENS_IN_CONFIG_TO_IGNORE.put(
         "IllegalToken",
@@ -280,7 +280,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
                 "TEXT_BLOCK_LITERAL_END",
                 "LITERAL_YIELD",
                 "SWITCH_RULE")
-            .collect(Collectors.toUnmodifiableSet()));
+            .collect(toUnmodifiableSet()));
     // we have no need to block specific token text
     CHECKSTYLE_TOKENS_IN_CONFIG_TO_IGNORE.put(
         "IllegalTokenText",
@@ -295,7 +295,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
                 "CHAR_LITERAL",
                 "TEXT_BLOCK_CONTENT",
                 "STRING_TEMPLATE_CONTENT")
-            .collect(Collectors.toUnmodifiableSet()));
+            .collect(toUnmodifiableSet()));
     // we do not use this check as it is deprecated
     CHECKSTYLE_TOKENS_IN_CONFIG_TO_IGNORE.put(
         "WriteTag",
@@ -306,7 +306,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
                 "ANNOTATION_FIELD_DEF",
                 "RECORD_DEF",
                 "COMPACT_CTOR_DEF")
-            .collect(Collectors.toUnmodifiableSet()));
+            .collect(toUnmodifiableSet()));
     // state of the configuration when test was made until reason found in
     // https://github.com/checkstyle/checkstyle/issues/3730
     CHECKSTYLE_TOKENS_IN_CONFIG_TO_IGNORE.put(
@@ -320,7 +320,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
                 "VARIABLE_DEF",
                 "RECORD_DEF",
                 "COMPACT_CTOR_DEF")
-            .collect(Collectors.toUnmodifiableSet()));
+            .collect(toUnmodifiableSet()));
     CHECKSTYLE_TOKENS_IN_CONFIG_TO_IGNORE.put(
         "NoLineWrap",
         Stream.of(
@@ -335,33 +335,33 @@ public class AllChecksTest extends AbstractModuleTestSupport {
                 "ENUM_DEF",
                 "INTERFACE_DEF",
                 "RECORD_DEF")
-            .collect(Collectors.toUnmodifiableSet()));
+            .collect(toUnmodifiableSet()));
     CHECKSTYLE_TOKENS_IN_CONFIG_TO_IGNORE.put(
         "NoWhitespaceAfter",
         Stream.of(
                 // whitespace after is preferred
                 "TYPECAST", "LITERAL_SYNCHRONIZED")
-            .collect(Collectors.toUnmodifiableSet()));
+            .collect(toUnmodifiableSet()));
     CHECKSTYLE_TOKENS_IN_CONFIG_TO_IGNORE.put(
         "SeparatorWrap",
         Stream.of(
                 // needs context to decide what type of parentheses should be separated or not
                 // which this check does not provide
                 "LPAREN", "RPAREN")
-            .collect(Collectors.toUnmodifiableSet()));
+            .collect(toUnmodifiableSet()));
     CHECKSTYLE_TOKENS_IN_CONFIG_TO_IGNORE.put(
         "NeedBraces",
         Stream.of(
                 // we prefer no braces here as it looks unusual even though they help avoid sharing
                 // scope of variables
                 "LITERAL_DEFAULT", "LITERAL_CASE")
-            .collect(Collectors.toUnmodifiableSet()));
+            .collect(toUnmodifiableSet()));
     CHECKSTYLE_TOKENS_IN_CONFIG_TO_IGNORE.put(
         "FinalParameters",
         Stream.of(
                 // we prefer these to be effectively final as to not damage readability
                 "FOR_EACH_CLAUSE", "LITERAL_CATCH")
-            .collect(Collectors.toUnmodifiableSet()));
+            .collect(toUnmodifiableSet()));
     CHECKSTYLE_TOKENS_IN_CONFIG_TO_IGNORE.put(
         "WhitespaceAround",
         Stream.of(
@@ -372,7 +372,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
                 "WILDCARD_TYPE",
                 "GENERIC_END",
                 "GENERIC_START")
-            .collect(Collectors.toUnmodifiableSet()));
+            .collect(toUnmodifiableSet()));
 
     // google
     GOOGLE_TOKENS_IN_CONFIG_TO_IGNORE.put(
@@ -381,13 +381,13 @@ public class AllChecksTest extends AbstractModuleTestSupport {
                 // state of the configuration when test was made until reason found in
                 // https://github.com/checkstyle/checkstyle/issues/3730
                 "ANNOTATION_DEF", "ANNOTATION_FIELD_DEF", "ENUM_CONSTANT_DEF", "PACKAGE_DEF")
-            .collect(Collectors.toUnmodifiableSet()));
+            .collect(toUnmodifiableSet()));
     GOOGLE_TOKENS_IN_CONFIG_TO_IGNORE.put(
         "AbbreviationAsWordInName",
         Stream.of(
                 // enum values should be uppercase
                 "ENUM_CONSTANT_DEF")
-            .collect(Collectors.toUnmodifiableSet()));
+            .collect(toUnmodifiableSet()));
     GOOGLE_TOKENS_IN_CONFIG_TO_IGNORE.put(
         "NoLineWrap",
         Stream.of(
@@ -400,7 +400,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
                 "INTERFACE_DEF",
                 "RECORD_DEF",
                 "COMPACT_CTOR_DEF")
-            .collect(Collectors.toUnmodifiableSet()));
+            .collect(toUnmodifiableSet()));
     GOOGLE_TOKENS_IN_CONFIG_TO_IGNORE.put(
         "SeparatorWrap",
         Stream.of(
@@ -417,13 +417,13 @@ public class AllChecksTest extends AbstractModuleTestSupport {
                 // which this check does not provide
                 "LPAREN",
                 "RPAREN")
-            .collect(Collectors.toUnmodifiableSet()));
+            .collect(toUnmodifiableSet()));
     GOOGLE_TOKENS_IN_CONFIG_TO_IGNORE.put(
         "NeedBraces",
         Stream.of(
                 // google doesn't require or prevent braces on these
                 "LAMBDA", "LITERAL_DEFAULT", "LITERAL_CASE")
-            .collect(Collectors.toUnmodifiableSet()));
+            .collect(toUnmodifiableSet()));
     GOOGLE_TOKENS_IN_CONFIG_TO_IGNORE.put(
         "EmptyBlock",
         Stream.of(
@@ -442,7 +442,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
                 "LITERAL_SYNCHRONIZED",
                 "LITERAL_WHILE",
                 "STATIC_INIT")
-            .collect(Collectors.toUnmodifiableSet()));
+            .collect(toUnmodifiableSet()));
     GOOGLE_TOKENS_IN_CONFIG_TO_IGNORE.put(
         "WhitespaceAround",
         Stream.of(
@@ -454,7 +454,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
                 "GENERIC_START",
                 "GENERIC_END",
                 "WILDCARD_TYPE")
-            .collect(Collectors.toUnmodifiableSet()));
+            .collect(toUnmodifiableSet()));
     GOOGLE_TOKENS_IN_CONFIG_TO_IGNORE.put(
         "IllegalTokenText",
         Stream.of(
@@ -469,7 +469,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
                 "CHAR_LITERAL",
                 "TEXT_BLOCK_CONTENT",
                 "STRING_TEMPLATE_CONTENT")
-            .collect(Collectors.toUnmodifiableSet()));
+            .collect(toUnmodifiableSet()));
     GOOGLE_TOKENS_IN_CONFIG_TO_IGNORE.put(
         "OperatorWrap",
         Stream.of(
@@ -490,7 +490,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
                 // COLON token ignored in check config, explained in
                 // https://github.com/checkstyle/checkstyle/issues/4122
                 "COLON")
-            .collect(Collectors.toUnmodifiableSet()));
+            .collect(toUnmodifiableSet()));
     GOOGLE_TOKENS_IN_CONFIG_TO_IGNORE.put(
         "NoWhitespaceBefore",
         Stream.of(
@@ -500,7 +500,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
                 // whitespace is necessary between a type annotation and ellipsis
                 // according '4.6.2 Horizontal whitespace point 9'
                 "ELLIPSIS")
-            .collect(Collectors.toUnmodifiableSet()));
+            .collect(toUnmodifiableSet()));
     INTERNAL_MODULES =
         Definitions.INTERNAL_MODULES.stream()
             .map(
@@ -508,7 +508,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
                   final String[] packageTokens = moduleName.split("\\.");
                   return packageTokens[packageTokens.length - 1];
                 })
-            .collect(Collectors.toUnmodifiableSet());
+            .collect(toUnmodifiableSet());
   }
 
   @Override
@@ -517,7 +517,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllModulesWithDefaultConfiguration() throws Exception {
+  void allModulesWithDefaultConfiguration() throws Exception {
     final String inputFilePath = getPath("InputAllChecksDefaultConfig.java");
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
@@ -537,7 +537,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testDefaultTokensAreSubsetOfAcceptableTokens() throws Exception {
+  void defaultTokensAreSubsetOfAcceptableTokens() throws Exception {
     for (Class<?> check : CheckUtil.getCheckstyleChecks()) {
       if (AbstractCheck.class.isAssignableFrom(check)) {
         final AbstractCheck testedCheck =
@@ -554,7 +554,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRequiredTokensAreSubsetOfAcceptableTokens() throws Exception {
+  void requiredTokensAreSubsetOfAcceptableTokens() throws Exception {
     for (Class<?> check : CheckUtil.getCheckstyleChecks()) {
       if (AbstractCheck.class.isAssignableFrom(check)) {
         final AbstractCheck testedCheck =
@@ -571,7 +571,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRequiredTokensAreSubsetOfDefaultTokens() throws Exception {
+  void requiredTokensAreSubsetOfDefaultTokens() throws Exception {
     for (Class<?> check : CheckUtil.getCheckstyleChecks()) {
       if (AbstractCheck.class.isAssignableFrom(check)) {
         final AbstractCheck testedCheck =
@@ -588,7 +588,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllModulesHaveMultiThreadAnnotation() throws Exception {
+  void allModulesHaveMultiThreadAnnotation() throws Exception {
     for (Class<?> module : CheckUtil.getCheckstyleModules()) {
       if (ModuleReflectionUtil.isRootModule(module)
           || ModuleReflectionUtil.isFilterModule(module)
@@ -608,7 +608,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllModulesAreReferencedInConfigFile() throws Exception {
+  void allModulesAreReferencedInConfigFile() throws Exception {
     final Set<String> modulesReferencedInConfig = CheckUtil.getConfigCheckStyleModules();
     final Set<String> moduleNames = CheckUtil.getSimpleNames(CheckUtil.getCheckstyleModules());
 
@@ -625,7 +625,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllCheckTokensAreReferencedInCheckstyleConfigFile() throws Exception {
+  void allCheckTokensAreReferencedInCheckstyleConfigFile() throws Exception {
     final Configuration configuration =
         ConfigurationUtil.loadConfiguration("config/checkstyle-checks.xml");
 
@@ -634,7 +634,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllCheckTokensAreReferencedInGoogleConfigFile() throws Exception {
+  void allCheckTokensAreReferencedInGoogleConfigFile() throws Exception {
     final Configuration configuration =
         ConfigurationUtil.loadConfiguration("src/main/resources/google_checks.xml");
 
@@ -732,7 +732,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllCheckstyleModulesHaveXdocDocumentation() throws Exception {
+  void allCheckstyleModulesHaveXdocDocumentation() throws Exception {
     final Set<String> checkstyleModulesNames =
         CheckUtil.getSimpleNames(CheckUtil.getCheckstyleModules());
     final Set<String> modulesNamesWhichHaveXdocs = XdocUtil.getModulesNamesWhichHaveXdoc();
@@ -754,7 +754,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllCheckstyleModulesInCheckstyleConfig() throws Exception {
+  void allCheckstyleModulesInCheckstyleConfig() throws Exception {
     final Set<String> configChecks = CheckUtil.getConfigCheckStyleModules();
     final Set<String> moduleNames = CheckUtil.getSimpleNames(CheckUtil.getCheckstyleModules());
     moduleNames.removeAll(INTERNAL_MODULES);
@@ -766,7 +766,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllCheckstyleChecksHaveMessage() throws Exception {
+  void allCheckstyleChecksHaveMessage() throws Exception {
     for (Class<?> module : CheckUtil.getCheckstyleChecks()) {
       final String name = module.getSimpleName();
       final Set<Field> messages = CheckUtil.getCheckMessages(module, false);
@@ -785,7 +785,7 @@ public class AllChecksTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAllCheckstyleMessages() throws Exception {
+  void allCheckstyleMessages() throws Exception {
     final Map<String, List<String>> usedMessages = new TreeMap<>();
 
     // test validity of messages from modules
--- a/src/test/java/com/puppycrawl/tools/checkstyle/internal/AllTestsTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/internal/AllTestsTest.java
@@ -42,10 +42,10 @@ import org.junit.jupiter.api.Test;
  * @noinspectionreason ClassIndependentOfModule - architecture of test modules requires this
  *     structure
  */
-public class AllTestsTest {
+final class AllTestsTest {
 
   @Test
-  public void testAllInputsHaveTest() throws Exception {
+  void allInputsHaveTest() throws Exception {
     final Map<String, List<String>> allTests = new HashMap<>();
 
     walk(
@@ -69,7 +69,7 @@ public class AllTestsTest {
   }
 
   @Test
-  public void testAllTestsHaveProductionCode() throws Exception {
+  void allTestsHaveProductionCode() throws Exception {
     final Map<String, List<String>> allTests = new HashMap<>();
 
     walk(
--- a/src/test/java/com/puppycrawl/tools/checkstyle/internal/ArchUnitSuperClassTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/internal/ArchUnitSuperClassTest.java
@@ -41,7 +41,7 @@ import java.util.Optional;
 import java.util.Set;
 import org.junit.jupiter.api.Test;
 
-public class ArchUnitSuperClassTest {
+final class ArchUnitSuperClassTest {
 
   /**
    * Classes not abiding to {@link #testChecksShouldHaveAllowedAbstractClassAsSuperclass()} rule.
@@ -90,7 +90,7 @@ public class ArchUnitSuperClassTest {
    * AbstractJavadocCheck} as their super class.
    */
   @Test
-  public void testChecksShouldHaveAllowedAbstractClassAsSuperclass() {
+  void checksShouldHaveAllowedAbstractClassAsSuperclass() {
     final JavaClasses checksPackage =
         new ClassFileImporter()
             .withImportOption(ImportOption.Predefined.DO_NOT_INCLUDE_TESTS)
@@ -134,7 +134,7 @@ public class ArchUnitSuperClassTest {
     public void check(JavaClass item, ConditionEvents events) {
       final Optional<JavaType> superclassOptional = item.getSuperclass();
       if (superclassOptional.isPresent()) {
-        final JavaClass superclass = superclassOptional.get().toErasure();
+        final JavaClass superclass = superclassOptional.orElseThrow().toErasure();
         if (!superclass.isEquivalentTo(expectedSuperclass)) {
           final String format = "<%s> is subclass of <%s> instead of <%s>";
           final String message =
--- a/src/test/java/com/puppycrawl/tools/checkstyle/internal/ArchUnitTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/internal/ArchUnitTest.java
@@ -32,7 +32,7 @@ import com.tngtech.archunit.lang.EvaluationResult;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class ArchUnitTest {
+final class ArchUnitTest {
 
   /**
    * Suppression list containing violations from {@code classShouldNotDependOnUtilPackages}
@@ -92,7 +92,7 @@ public class ArchUnitTest {
    * we need to make checkstyle's Check on this.
    */
   @Test
-  public void nonProtectedCheckMethodsTest() {
+  void nonProtectedCheckMethodsTest() {
     // This list contains methods which have been overridden and are set to ignore in this test.
     final String[] methodsWithOverrideAnnotation = {
       "processFiltered",
@@ -129,7 +129,7 @@ public class ArchUnitTest {
    * Therefore classes in api should not depend on them.
    */
   @Test
-  public void testClassesInApiDoNotDependOnClassesInUtil() {
+  void classesInApiDoNotDependOnClassesInUtil() {
     final JavaClasses apiPackage =
         new ClassFileImporter()
             .withImportOption(ImportOption.Predefined.DO_NOT_INCLUDE_TESTS)
--- a/src/test/java/com/puppycrawl/tools/checkstyle/internal/CliOptionsXdocsSyncTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/internal/CliOptionsXdocsSyncTest.java
@@ -20,6 +20,7 @@
 package com.puppycrawl.tools.checkstyle.internal;
 
 import static com.google.common.truth.Truth.assertWithMessage;
+import static java.util.stream.Collectors.toUnmodifiableSet;
 
 import com.puppycrawl.tools.checkstyle.internal.utils.XmlUtil;
 import java.nio.file.Files;
@@ -32,7 +33,6 @@ import java.util.Map;
 import java.util.Set;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 import org.junit.jupiter.api.Test;
 import org.w3c.dom.Document;
 import org.w3c.dom.Node;
@@ -40,10 +40,10 @@ import org.w3c.dom.NodeList;
 import picocli.CommandLine;
 import picocli.CommandLine.Model.OptionSpec;
 
-public class CliOptionsXdocsSyncTest {
+final class CliOptionsXdocsSyncTest {
 
   @Test
-  public void validateCliDocSections() throws Exception {
+  void validateCliDocSections() throws Exception {
     final Map<String, String> cmdDesc = new HashMap<>();
 
     final NodeList sections = getSectionsFromXdoc("src/xdocs/cmdline.xml.vm");
@@ -85,7 +85,7 @@ public class CliOptionsXdocsSyncTest {
   }
 
   @Test
-  public void validateCliUsageSection() throws Exception {
+  void validateCliUsageSection() throws Exception {
     final NodeList sections = getSectionsFromXdoc("src/xdocs/cmdline.xml.vm");
     final Node usageSource = XmlUtil.getFirstChildElement(sections.item(2));
     final String usageText = XmlUtil.getFirstChildElement(usageSource).getTextContent();
@@ -99,12 +99,12 @@ public class CliOptionsXdocsSyncTest {
     final Set<String> shortParamsMain =
         commandLine.getCommandSpec().options().stream()
             .map(OptionSpec::shortestName)
-            .collect(Collectors.toUnmodifiableSet());
+            .collect(toUnmodifiableSet());
     final Set<String> longParamsMain =
         commandLine.getCommandSpec().options().stream()
             .map(OptionSpec::longestName)
             .filter(names -> names.length() != 2)
-            .collect(Collectors.toUnmodifiableSet());
+            .collect(toUnmodifiableSet());
 
     assertWithMessage("Short parameters in Main.java and cmdline" + ".xml.vm should match")
         .that(shortParamsMain)
@@ -138,7 +138,7 @@ public class CliOptionsXdocsSyncTest {
       result =
           XmlUtil.getChildrenElements(node).stream()
               .map(Node::getTextContent)
-              .collect(Collectors.toUnmodifiableSet());
+              .collect(toUnmodifiableSet());
     }
     return result;
   }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/internal/CommitValidationTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/internal/CommitValidationTest.java
@@ -20,16 +20,17 @@
 package com.puppycrawl.tools.checkstyle.internal;
 
 import static com.google.common.truth.Truth.assertWithMessage;
+import static java.util.Collections.emptyIterator;
+import static java.util.stream.Collectors.toUnmodifiableList;
 
+import com.google.common.collect.ImmutableList;
 import java.io.IOException;
-import java.util.Collections;
 import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Spliterator;
 import java.util.Spliterators;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
 import org.eclipse.jgit.api.Git;
 import org.eclipse.jgit.api.errors.GitAPIException;
@@ -59,10 +60,10 @@ import org.junit.jupiter.api.Test;
  *
  * <p>Filtered commit list is checked if their messages has proper structure.
  */
-public class CommitValidationTest {
+final class CommitValidationTest {
 
   private static final List<String> USERS_EXCLUDED_FROM_VALIDATION =
-      Collections.singletonList("dependabot[bot]");
+      ImmutableList.of("dependabot[bot]");
 
   private static final String ISSUE_COMMIT_MESSAGE_REGEX_PATTERN = "^Issue #\\d+: .*$";
   private static final String PR_COMMIT_MESSAGE_REGEX_PATTERN = "^Pull #\\d+: .*$";
@@ -97,14 +98,14 @@ public class CommitValidationTest {
       CommitsResolutionMode.BY_LAST_COMMIT_AUTHOR;
 
   @Test
-  public void testHasCommits() throws Exception {
+  void hasCommits() throws Exception {
     final List<RevCommit> lastCommits = getCommitsToCheck();
 
     assertWithMessage("must have at least one commit to validate").that(lastCommits).isNotEmpty();
   }
 
   @Test
-  public void testCommitMessage() {
+  void commitMessage() {
     assertWithMessage("should not accept commit message with periods on end")
         .that(validateCommitMessage("minor: Test. Test."))
         .isEqualTo(3);
@@ -146,7 +147,7 @@ public class CommitValidationTest {
   }
 
   @Test
-  public void testReleaseCommitMessage() {
+  void releaseCommitMessage() {
     assertWithMessage("should accept release commit message for preparing release")
         .that(
             validateCommitMessage("[maven-release-plugin] " + "prepare release checkstyle-10.8.0"))
@@ -161,7 +162,7 @@ public class CommitValidationTest {
   }
 
   @Test
-  public void testRevertCommitMessage() {
+  void revertCommitMessage() {
     assertWithMessage("should accept proper revert commit message")
         .that(
             validateCommitMessage(
@@ -179,7 +180,7 @@ public class CommitValidationTest {
   }
 
   @Test
-  public void testSupplementalPrefix() {
+  void supplementalPrefix() {
     assertWithMessage("should accept commit message with supplemental prefix")
         .that(0)
         .isEqualTo(
@@ -209,7 +210,7 @@ public class CommitValidationTest {
   }
 
   @Test
-  public void testCommitMessageHasProperStructure() throws Exception {
+  void commitMessageHasProperStructure() throws Exception {
     final List<RevCommit> lastCommits = getCommitsToCheck();
     for (RevCommit commit : filterValidCommits(lastCommits)) {
       final String commitMessage = commit.getFullMessage();
@@ -295,7 +296,7 @@ public class CommitValidationTest {
         second = git.log().add(secondParent).call().iterator();
       } else {
         first = git.log().call().iterator();
-        second = Collections.emptyIterator();
+        second = emptyIterator();
       }
 
       revCommitIteratorPair =
@@ -317,7 +318,7 @@ public class CommitValidationTest {
         Spliterators.spliteratorUnknownSize(previousCommitsIterator, Spliterator.ORDERED);
     return StreamSupport.stream(spliterator, false)
         .limit(PREVIOUS_COMMITS_TO_CHECK_COUNT)
-        .collect(Collectors.toUnmodifiableList());
+        .collect(toUnmodifiableList());
   }
 
   private static List<RevCommit> getCommitsByLastCommitAuthor(
@@ -384,8 +385,8 @@ public class CommitValidationTest {
     private final Iterator<RevCommit> second;
 
     private RevCommitsPair() {
-      first = Collections.emptyIterator();
-      second = Collections.emptyIterator();
+      first = emptyIterator();
+      second = emptyIterator();
     }
 
     private RevCommitsPair(Iterator<RevCommit> first, Iterator<RevCommit> second) {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/internal/ImmutabilityTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/internal/ImmutabilityTest.java
@@ -25,7 +25,10 @@ import static com.tngtech.archunit.lang.conditions.ArchPredicates.are;
 import static com.tngtech.archunit.lang.conditions.ArchPredicates.have;
 import static com.tngtech.archunit.lang.syntax.ArchRuleDefinition.classes;
 import static com.tngtech.archunit.lang.syntax.ArchRuleDefinition.fields;
+import static java.util.function.Function.identity;
+import static java.util.stream.Collectors.toUnmodifiableMap;
 
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
 import com.puppycrawl.tools.checkstyle.GlobalStatefulCheck;
 import com.puppycrawl.tools.checkstyle.StatelessCheck;
@@ -51,11 +54,9 @@ import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
-import java.util.function.Function;
-import java.util.stream.Collectors;
 import org.junit.jupiter.api.Test;
 
-public class ImmutabilityTest {
+final class ImmutabilityTest {
 
   /** Immutable types canonical names. */
   private static final Set<String> IMMUTABLE_TYPES =
@@ -99,7 +100,7 @@ public class ImmutabilityTest {
 
   /** List of fields not following {@link #testUtilClassesImmutability()} rule. */
   private static final Set<String> SUPPRESSED_FIELDS_IN_UTIL_CLASSES =
-      Set.of(
+      ImmutableSet.of(
           "com.puppycrawl.tools.checkstyle.utils.TokenUtil.TOKEN_IDS",
           "com.puppycrawl.tools.checkstyle.utils.XpathUtil.TOKEN_TYPES_WITH_TEXT_ATTRIBUTE");
 
@@ -164,7 +165,7 @@ public class ImmutabilityTest {
 
   /** List of classes not following {@link #testClassesWithMutableFieldsShouldBeStateful()} rule. */
   private static final Set<String> SUPPRESSED_CLASSES_FOR_STATEFUL_CHECK_RULE =
-      Set.of("com.puppycrawl.tools.checkstyle.checks.whitespace.ParenPadCheck");
+      ImmutableSet.of("com.puppycrawl.tools.checkstyle.checks.whitespace.ParenPadCheck");
 
   private static final JavaClasses CHECKSTYLE_CHECKS =
       new ClassFileImporter()
@@ -191,13 +192,11 @@ public class ImmutabilityTest {
   /** Map of module full name to module details. */
   private static final Map<String, ModuleDetails> MODULE_DETAILS_MAP =
       XmlMetaReader.readAllModulesIncludingThirdPartyIfAny().stream()
-          .collect(
-              Collectors.toUnmodifiableMap(
-                  ModuleDetails::getFullQualifiedName, Function.identity()));
+          .collect(toUnmodifiableMap(ModuleDetails::getFullQualifiedName, identity()));
 
   /** Test to ensure that fields in util classes are immutable. */
   @Test
-  public void testUtilClassesImmutability() {
+  void utilClassesImmutability() {
     final JavaClasses utilClasses =
         new ClassFileImporter()
             .withImportOption(ImportOption.Predefined.DO_NOT_INCLUDE_TESTS)
@@ -225,7 +224,7 @@ public class ImmutabilityTest {
 
   /** Test to ensure modules annotated with {@link StatelessCheck} contain immutable fields. */
   @Test
-  public void testFieldsInStatelessChecksShouldBeImmutable() {
+  void fieldsInStatelessChecksShouldBeImmutable() {
     final DescribedPredicate<JavaField> moduleProperties = new ModulePropertyPredicate();
 
     final ArchCondition<JavaField> beSuppressedField =
@@ -247,7 +246,7 @@ public class ImmutabilityTest {
 
   /** Test to ensure classes with immutable fields are annotated with {@link StatelessCheck}. */
   @Test
-  public void testClassesWithImmutableFieldsShouldBeStateless() {
+  void classesWithImmutableFieldsShouldBeStateless() {
     final ArchCondition<JavaClass> beSuppressedClass =
         new SuppressionArchCondition<>(
             SUPPRESSED_CLASSES_FOR_STATELESS_CHECK_RULE, "be suppressed");
@@ -269,7 +268,7 @@ public class ImmutabilityTest {
    * {@link GlobalStatefulCheck}.
    */
   @Test
-  public void testClassesWithMutableFieldsShouldBeStateful() {
+  void classesWithMutableFieldsShouldBeStateful() {
     final ArchCondition<JavaClass> beSuppressedClass =
         new SuppressionArchCondition<>(SUPPRESSED_CLASSES_FOR_STATEFUL_CHECK_RULE, "be suppressed");
 
@@ -352,7 +351,7 @@ public class ImmutabilityTest {
                 "Field <%s> should %s in %s",
                 item.getFullName(),
                 getDescription(),
-                item.getSourceCodeLocation().toString());
+                item.getSourceCodeLocation());
         events.add(SimpleConditionEvent.violated(item, message));
       }
     }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/internal/XdocsJavaDocsTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/internal/XdocsJavaDocsTest.java
@@ -68,7 +68,7 @@ import org.w3c.dom.NamedNodeMap;
 import org.w3c.dom.Node;
 import org.w3c.dom.NodeList;
 
-public class XdocsJavaDocsTest extends AbstractModuleTestSupport {
+final class XdocsJavaDocsTest extends AbstractModuleTestSupport {
   private static final Map<String, Class<?>> FULLY_QUALIFIED_CLASS_NAMES =
       ImmutableMap.<String, Class<?>>builder()
           .put("int", int.class)
@@ -115,7 +115,7 @@ public class XdocsJavaDocsTest extends AbstractModuleTestSupport {
   }
 
   @BeforeEach
-  public void setUp() throws Exception {
+  void setUp() throws Exception {
     final DefaultConfiguration checkConfig =
         new DefaultConfiguration(JavaDocCapture.class.getName());
     checker = createChecker(checkConfig);
@@ -129,7 +129,7 @@ public class XdocsJavaDocsTest extends AbstractModuleTestSupport {
    *     method
    */
   @Test
-  public void testAllCheckSectionJavaDocs() throws Exception {
+  void allCheckSectionJavaDocs() throws Exception {
     final ModuleFactory moduleFactory = TestUtil.getPackageObjectFactory();
 
     for (Path path : XdocUtil.getXdocsConfigFilePaths(XdocUtil.getXdocsFilePaths())) {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/internal/XdocsMobileWrapperTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/internal/XdocsMobileWrapperTest.java
@@ -21,6 +21,7 @@ package com.puppycrawl.tools.checkstyle.internal;
 
 import static com.google.common.truth.Truth.assertWithMessage;
 
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.internal.utils.XdocUtil;
 import com.puppycrawl.tools.checkstyle.internal.utils.XmlUtil;
 import java.io.File;
@@ -32,12 +33,12 @@ import org.w3c.dom.Document;
 import org.w3c.dom.Node;
 import org.w3c.dom.NodeList;
 
-public class XdocsMobileWrapperTest {
+final class XdocsMobileWrapperTest {
 
-  private static final Set<String> NODES_TO_WRAP = Set.of("pre", "table", "svg", "img");
+  private static final Set<String> NODES_TO_WRAP = ImmutableSet.of("pre", "table", "svg", "img");
 
   @Test
-  public void testAllCheckSectionMobileWrapper() throws Exception {
+  void allCheckSectionMobileWrapper() throws Exception {
     for (Path path : XdocUtil.getXdocsFilePaths()) {
       final File file = path.toFile();
       final String fileName = file.getName();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/internal/XdocsPagesTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/internal/XdocsPagesTest.java
@@ -21,6 +21,10 @@ package com.puppycrawl.tools.checkstyle.internal;
 
 import static com.google.common.truth.Truth.assertWithMessage;
 import static java.lang.Integer.parseInt;
+import static java.util.Collections.unmodifiableSet;
+import static java.util.regex.Pattern.DOTALL;
+import static java.util.stream.Collectors.joining;
+import static java.util.stream.Collectors.toUnmodifiableSet;
 
 import com.puppycrawl.tools.checkstyle.Checker;
 import com.puppycrawl.tools.checkstyle.ConfigurationLoader;
@@ -55,7 +59,6 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.BitSet;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
@@ -69,7 +72,6 @@ import java.util.Set;
 import java.util.TreeSet;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 import java.util.stream.Stream;
 import org.apache.commons.beanutils.PropertyUtils;
@@ -85,7 +87,7 @@ import org.xml.sax.InputSource;
  * following commands have to be executed: - mvn clean compile - Required for next command - mvn
  * plexus-component-metadata:generate-metadata - Required to find custom macros and parser
  */
-public class XdocsPagesTest {
+final class XdocsPagesTest {
   private static final Path SITE_PATH = Paths.get("src/site/site.xml");
 
   private static final Path AVAILABLE_CHECKS_PATH = Paths.get("src/xdocs/checks.xml");
@@ -151,7 +153,7 @@ public class XdocsPagesTest {
           "CustomImportOrder.customImportOrderRules");
 
   private static final Set<String> SUN_MODULES =
-      Collections.unmodifiableSet(CheckUtil.getConfigSunStyleModules());
+      unmodifiableSet(CheckUtil.getConfigSunStyleModules());
   // ignore the not yet properly covered modules while testing newly added ones
   // add proper sections to the coverage report and integration tests
   // and then remove this list eventually
@@ -221,7 +223,7 @@ public class XdocsPagesTest {
           "WhitespaceAround");
 
   private static final Set<String> GOOGLE_MODULES =
-      Collections.unmodifiableSet(CheckUtil.getConfigGoogleStyleModules());
+      unmodifiableSet(CheckUtil.getConfigGoogleStyleModules());
 
   /**
    * Generate xdoc content from templates before validation. This method will be removed once <a
@@ -230,12 +232,12 @@ public class XdocsPagesTest {
    * @throws Exception if something goes wrong
    */
   @BeforeAll
-  public static void generateXdocContent() throws Exception {
+  static void generateXdocContent() throws Exception {
     XdocGenerator.generateXdocContent();
   }
 
   @Test
-  public void testAllChecksPresentOnAvailableChecksPage() throws Exception {
+  void allChecksPresentOnAvailableChecksPage() throws Exception {
     final String availableChecks = Files.readString(AVAILABLE_CHECKS_PATH);
 
     CheckUtil.getSimpleNames(CheckUtil.getCheckstyleChecks()).stream()
@@ -263,7 +265,7 @@ public class XdocsPagesTest {
   }
 
   @Test
-  public void testAllConfigsHaveLinkInSite() throws Exception {
+  void allConfigsHaveLinkInSite() throws Exception {
     final String siteContent = Files.readString(SITE_PATH);
 
     for (Path path : XdocUtil.getXdocsConfigFilePaths(XdocUtil.getXdocsFilePaths())) {
@@ -280,8 +282,8 @@ public class XdocsPagesTest {
   }
 
   @Test
-  public void testAllChecksPageInSyncWithChecksSummaries() throws Exception {
-    final Pattern endOfSentence = Pattern.compile("(.*?\\.)\\s", Pattern.DOTALL);
+  void allChecksPageInSyncWithChecksSummaries() throws Exception {
+    final Pattern endOfSentence = Pattern.compile("(.*?\\.)\\s", DOTALL);
     final Map<String, String> summaries = readSummaries();
 
     for (Path path : XdocUtil.getXdocsConfigFilePaths(XdocUtil.getXdocsFilePaths())) {
@@ -331,7 +333,7 @@ public class XdocsPagesTest {
   }
 
   @Test
-  public void testCategoryIndexPageTableInSyncWithAllChecksPageTable() throws Exception {
+  void categoryIndexPageTableInSyncWithAllChecksPageTable() throws Exception {
     final Map<String, String> summaries = readSummaries();
     for (Path path : XdocUtil.getXdocsConfigFilePaths(XdocUtil.getXdocsFilePaths())) {
       final String fileName = path.getFileName().toString();
@@ -384,7 +386,7 @@ public class XdocsPagesTest {
   }
 
   @Test
-  public void testAllSubSections() throws Exception {
+  void allSubSections() throws Exception {
     for (Path path : XdocUtil.getXdocsFilePaths()) {
       final String input = Files.readString(path);
       final String fileName = path.getFileName().toString();
@@ -441,7 +443,7 @@ public class XdocsPagesTest {
   }
 
   @Test
-  public void testAllXmlExamples() throws Exception {
+  void allXmlExamples() throws Exception {
     for (Path path : XdocUtil.getXdocsFilePaths()) {
       final String input = Files.readString(path);
       final String fileName = path.getFileName().toString();
@@ -564,7 +566,7 @@ public class XdocsPagesTest {
   }
 
   @Test
-  public void testAllCheckSections() throws Exception {
+  void allCheckSections() throws Exception {
     final ModuleFactory moduleFactory = TestUtil.getPackageObjectFactory();
 
     for (Path path : XdocUtil.getXdocsConfigFilePaths(XdocUtil.getXdocsFilePaths())) {
@@ -624,7 +626,7 @@ public class XdocsPagesTest {
    *     method
    */
   @Test
-  public void testAllCheckSectionsEx() throws Exception {
+  void allCheckSectionsEx() throws Exception {
     final ModuleFactory moduleFactory = TestUtil.getPackageObjectFactory();
 
     final Path path = Paths.get(XdocUtil.DIRECTORY_PATH + "/config.xml");
@@ -1364,7 +1366,7 @@ public class XdocsPagesTest {
         final Object[] array = (Object[]) value;
         valuesStream = Arrays.stream(array);
       }
-      result = valuesStream.map(String.class::cast).sorted().collect(Collectors.joining(", "));
+      result = valuesStream.map(String.class::cast).sorted().collect(joining(", "));
     }
 
     if (result.isEmpty()) {
@@ -1393,8 +1395,7 @@ public class XdocsPagesTest {
     } else {
       stream = Arrays.stream((int[]) value);
     }
-    String result =
-        stream.mapToObj(TokenUtil::getTokenName).sorted().collect(Collectors.joining(", "));
+    String result = stream.mapToObj(TokenUtil::getTokenName).sorted().collect(joining(", "));
     if (result.isEmpty()) {
       result = "{}";
     }
@@ -1470,7 +1471,7 @@ public class XdocsPagesTest {
       result =
           XmlUtil.getChildrenElements(node).stream()
               .map(Node::getTextContent)
-              .collect(Collectors.toUnmodifiableSet());
+              .collect(toUnmodifiableSet());
     }
     return result;
   }
@@ -1684,7 +1685,7 @@ public class XdocsPagesTest {
   }
 
   @Test
-  public void testAllStyleRules() throws Exception {
+  void allStyleRules() throws Exception {
     for (Path path : XdocUtil.getXdocsStyleFilePaths(XdocUtil.getXdocsFilePaths())) {
       final String fileName = path.getFileName().toString();
       final String styleName = fileName.substring(0, fileName.lastIndexOf('_'));
@@ -1989,7 +1990,7 @@ public class XdocsPagesTest {
   }
 
   @Test
-  public void testAllExampleMacrosHaveParagraphWithIdBeforeThem() throws Exception {
+  void allExampleMacrosHaveParagraphWithIdBeforeThem() throws Exception {
     for (Path path : XdocUtil.getXdocsTemplatesFilePaths()) {
       final String fileName = path.getFileName().toString();
       final String input = Files.readString(path);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/internal/XdocsUrlTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/internal/XdocsUrlTest.java
@@ -20,6 +20,7 @@
 package com.puppycrawl.tools.checkstyle.internal;
 
 import static com.google.common.truth.Truth.assertWithMessage;
+import static java.util.stream.Collectors.toUnmodifiableSet;
 
 import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
 import com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck;
@@ -35,14 +36,13 @@ import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
-import java.util.stream.Collectors;
 import javax.xml.parsers.SAXParser;
 import javax.xml.parsers.SAXParserFactory;
 import org.junit.jupiter.api.Test;
 import org.xml.sax.Attributes;
 import org.xml.sax.helpers.DefaultHandler;
 
-public class XdocsUrlTest {
+final class XdocsUrlTest {
 
   private static final String PACKAGE_NAME = "src/main/java/com/puppycrawl/tools/checkstyle/checks";
 
@@ -74,7 +74,7 @@ public class XdocsUrlTest {
                   return AbstractCheck.class.isAssignableFrom(clazz)
                       || AbstractFileSetCheck.class.isAssignableFrom(clazz);
                 })
-            .collect(Collectors.toUnmodifiableSet());
+            .collect(toUnmodifiableSet());
     for (Class<?> check : treeWalkerOrFileSetCheckSet) {
       final String checkName = check.getSimpleName();
       if (!TREE_WORKER.equals(checkName)) {
@@ -96,7 +96,7 @@ public class XdocsUrlTest {
   }
 
   @Test
-  public void testXdocsUrl() throws Exception {
+  void xdocsUrl() throws Exception {
     final SAXParserFactory parserFactory = SAXParserFactory.newInstance();
     final SAXParser parser = parserFactory.newSAXParser();
     final DummyHandler checkHandler = new DummyHandler();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/internal/XpathRegressionTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/internal/XpathRegressionTest.java
@@ -20,7 +20,12 @@
 package com.puppycrawl.tools.checkstyle.internal;
 
 import static com.google.common.truth.Truth.assertWithMessage;
+import static java.util.function.Function.identity;
+import static java.util.stream.Collectors.toCollection;
+import static java.util.stream.Collectors.toUnmodifiableMap;
+import static java.util.stream.Collectors.toUnmodifiableSet;
 
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.Definitions;
 import com.puppycrawl.tools.checkstyle.checks.javadoc.AbstractJavadocCheck;
@@ -38,18 +43,16 @@ import java.util.HashSet;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
-import java.util.function.Function;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-public class XpathRegressionTest extends AbstractModuleTestSupport {
+final class XpathRegressionTest extends AbstractModuleTestSupport {
 
   // Checks that not compatible with SuppressionXpathFilter
   public static final Set<String> INCOMPATIBLE_CHECK_NAMES =
-      Set.of(
+      ImmutableSet.of(
           "NoCodeInFile (reason is that AST is not generated for a file not containing code)",
           "Regexp (reason is at  #7759)",
           "RegexpSinglelineJava (reason is at  #7759)");
@@ -79,7 +82,7 @@ public class XpathRegressionTest extends AbstractModuleTestSupport {
   // Older regex-based checks that are under INCOMPATIBLE_JAVADOC_CHECK_NAMES
   // but not subclasses of AbstractJavadocCheck.
   private static final Set<Class<?>> REGEXP_JAVADOC_CHECKS =
-      Set.of(
+      ImmutableSet.of(
           JavadocStyleCheck.class,
           JavadocMethodCheck.class,
           JavadocTypeCheck.class,
@@ -115,7 +118,7 @@ public class XpathRegressionTest extends AbstractModuleTestSupport {
           "VisibilityModifier");
 
   // Modules that will never have xpath support ever because they not report violations
-  private static final Set<String> NO_VIOLATION_MODULES = Set.of("SuppressWarningsHolder");
+  private static final Set<String> NO_VIOLATION_MODULES = ImmutableSet.of("SuppressWarningsHolder");
 
   private static final Set<String> SIMPLE_CHECK_NAMES = getSimpleCheckNames();
   private static final Map<String, String> ALLOWED_DIRECTORY_AND_CHECKS =
@@ -136,9 +139,7 @@ public class XpathRegressionTest extends AbstractModuleTestSupport {
 
   private static Map<String, String> getAllowedDirectoryAndChecks() {
     return SIMPLE_CHECK_NAMES.stream()
-        .collect(
-            Collectors.toUnmodifiableMap(
-                id -> id.toLowerCase(Locale.ENGLISH), Function.identity()));
+        .collect(toUnmodifiableMap(id -> id.toLowerCase(Locale.ENGLISH), identity()));
   }
 
   private static Set<String> getInternalModules() {
@@ -148,11 +149,11 @@ public class XpathRegressionTest extends AbstractModuleTestSupport {
               final String[] packageTokens = moduleName.split("\\.");
               return packageTokens[packageTokens.length - 1];
             })
-        .collect(Collectors.toUnmodifiableSet());
+        .collect(toUnmodifiableSet());
   }
 
   @BeforeEach
-  public void setUp() throws Exception {
+  void setUp() throws Exception {
     javaDir = Paths.get("src/it/java/" + getPackageLocation());
     inputDir = Paths.get(getPath(""));
   }
@@ -168,12 +169,12 @@ public class XpathRegressionTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void validateIncompatibleJavadocCheckNames() throws IOException {
+  void validateIncompatibleJavadocCheckNames() throws IOException {
     // subclasses of AbstractJavadocCheck
     final Set<Class<?>> abstractJavadocCheckNames =
         CheckUtil.getCheckstyleChecks().stream()
             .filter(AbstractJavadocCheck.class::isAssignableFrom)
-            .collect(Collectors.toCollection(HashSet::new));
+            .collect(toCollection(HashSet::new));
     // add the extra checks
     abstractJavadocCheckNames.addAll(REGEXP_JAVADOC_CHECKS);
     final Set<String> abstractJavadocCheckSimpleNames =
@@ -187,7 +188,7 @@ public class XpathRegressionTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void validateIntegrationTestClassNames() throws Exception {
+  void validateIntegrationTestClassNames() throws Exception {
     final Set<String> compatibleChecks = new HashSet<>();
     final Pattern pattern = Pattern.compile("^XpathRegression(.+)Test\\.java$");
     try (DirectoryStream<Path> javaPaths = Files.newDirectoryStream(javaDir)) {
@@ -231,7 +232,7 @@ public class XpathRegressionTest extends AbstractModuleTestSupport {
     final Set<String> allChecks = new HashSet<>(SIMPLE_CHECK_NAMES);
     allChecks.removeAll(INCOMPATIBLE_JAVADOC_CHECK_NAMES);
     allChecks.removeAll(INCOMPATIBLE_CHECK_NAMES);
-    allChecks.removeAll(Set.of("Regexp", "RegexpSinglelineJava", "NoCodeInFile"));
+    allChecks.removeAll(ImmutableSet.of("Regexp", "RegexpSinglelineJava", "NoCodeInFile"));
     allChecks.removeAll(MISSING_CHECK_NAMES);
     allChecks.removeAll(NO_VIOLATION_MODULES);
     allChecks.removeAll(compatibleChecks);
@@ -246,7 +247,7 @@ public class XpathRegressionTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void validateInputFiles() throws Exception {
+  void validateInputFiles() throws Exception {
     try (DirectoryStream<Path> dirs = Files.newDirectoryStream(inputDir)) {
       for (Path dir : dirs) {
         // input directory must be named in lower case
--- a/src/test/java/com/puppycrawl/tools/checkstyle/internal/testmodules/CheckstyleAntTaskLogStub.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/internal/testmodules/CheckstyleAntTaskLogStub.java
@@ -19,9 +19,10 @@
 
 package com.puppycrawl.tools.checkstyle.internal.testmodules;
 
+import static java.util.Collections.unmodifiableList;
+
 import com.puppycrawl.tools.checkstyle.ant.CheckstyleAntTask;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 
 public final class CheckstyleAntTaskLogStub extends CheckstyleAntTask {
@@ -39,6 +40,6 @@ public final class CheckstyleAntTaskLogStub extends CheckstyleAntTask {
   }
 
   public List<MessageLevelPair> getLoggedMessages() {
-    return Collections.unmodifiableList(loggedMessages);
+    return unmodifiableList(loggedMessages);
   }
 }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/internal/testmodules/CheckstyleAntTaskStub.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/internal/testmodules/CheckstyleAntTaskStub.java
@@ -19,16 +19,16 @@
 
 package com.puppycrawl.tools.checkstyle.internal.testmodules;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.ant.CheckstyleAntTask;
 import java.io.File;
-import java.util.Collections;
 import java.util.List;
 
 public class CheckstyleAntTaskStub extends CheckstyleAntTask {
 
   @Override
   protected List<File> scanFileSets() {
-    return Collections.singletonList(new MockFile());
+    return ImmutableList.of(new MockFile());
   }
 
   private static final class MockFile extends File {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/internal/testmodules/TestRootModuleChecker.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/internal/testmodules/TestRootModuleChecker.java
@@ -19,13 +19,14 @@
 
 package com.puppycrawl.tools.checkstyle.internal.testmodules;
 
+import static java.util.Collections.unmodifiableList;
+
 import com.puppycrawl.tools.checkstyle.api.AuditListener;
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
 import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.api.RootModule;
 import java.io.File;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 
 public class TestRootModuleChecker implements RootModule {
@@ -85,7 +86,7 @@ public class TestRootModuleChecker implements RootModule {
   }
 
   public static List<File> getFilesToCheck() {
-    return Collections.unmodifiableList(filesToCheck);
+    return unmodifiableList(filesToCheck);
   }
 
   public static Configuration getConfig() {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/internal/utils/CheckUtil.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/internal/utils/CheckUtil.java
@@ -19,6 +19,9 @@
 
 package com.puppycrawl.tools.checkstyle.internal.utils;
 
+import static java.util.stream.Collectors.toCollection;
+import static java.util.stream.Collectors.toUnmodifiableSet;
+
 import com.google.common.reflect.ClassPath;
 import com.puppycrawl.tools.checkstyle.api.FileText;
 import com.puppycrawl.tools.checkstyle.checks.coding.AbstractSuperCheck;
@@ -41,7 +44,6 @@ import java.util.HashSet;
 import java.util.Locale;
 import java.util.Properties;
 import java.util.Set;
-import java.util.stream.Collectors;
 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;
 import org.w3c.dom.Document;
@@ -86,7 +88,7 @@ public final class CheckUtil {
 
               return name;
             })
-        .collect(Collectors.toCollection(HashSet::new));
+        .collect(toCollection(HashSet::new));
   }
 
   /**
@@ -145,7 +147,7 @@ public final class CheckUtil {
     final String packageName = "com.puppycrawl.tools.checkstyle";
     return getCheckstyleModulesRecursive(packageName, loader).stream()
         .filter(ModuleReflectionUtil::isCheckstyleTreeWalkerCheck)
-        .collect(Collectors.toUnmodifiableSet());
+        .collect(toUnmodifiableSet());
   }
 
   /**
@@ -176,7 +178,7 @@ public final class CheckUtil {
         .map(ClassPath.ClassInfo::load)
         .filter(ModuleReflectionUtil::isCheckstyleModule)
         .filter(CheckUtil::isFromAllowedPackages)
-        .collect(Collectors.toUnmodifiableSet());
+        .collect(toUnmodifiableSet());
   }
 
   /**
--- a/src/test/java/com/puppycrawl/tools/checkstyle/internal/utils/XdocGenerator.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/internal/utils/XdocGenerator.java
@@ -19,11 +19,12 @@
 
 package com.puppycrawl.tools.checkstyle.internal.utils;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import com.puppycrawl.tools.checkstyle.site.XdocsTemplateParser;
 import com.puppycrawl.tools.checkstyle.site.XdocsTemplateSinkFactory;
 import java.io.File;
 import java.io.Reader;
-import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.StandardCopyOption;
@@ -57,11 +58,10 @@ public final class XdocGenerator {
           (XdocsTemplateSinkFactory) plexus.lookup(SinkFactory.ROLE, XDOCS_TEMPLATE_HINT);
       final Sink sink =
           sinkFactory.createSink(
-              tempFile.getParentFile(), tempFile.getName(), String.valueOf(StandardCharsets.UTF_8));
+              tempFile.getParentFile(), tempFile.getName(), String.valueOf(UTF_8));
       final XdocsTemplateParser parser =
           (XdocsTemplateParser) plexus.lookup(Parser.ROLE, XDOCS_TEMPLATE_HINT);
-      try (Reader reader =
-          ReaderFactory.newReader(inputFile, String.valueOf(StandardCharsets.UTF_8))) {
+      try (Reader reader = ReaderFactory.newReader(inputFile, String.valueOf(UTF_8))) {
         parser.parse(reader, sink);
       } finally {
         sink.close();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/internal/utils/XdocUtil.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/internal/utils/XdocUtil.java
@@ -19,13 +19,14 @@
 
 package com.puppycrawl.tools.checkstyle.internal.utils;
 
+import static java.util.stream.Collectors.toUnmodifiableSet;
+
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.HashSet;
 import java.util.Set;
-import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;
@@ -64,7 +65,7 @@ public final class XdocUtil {
               return attr.isRegularFile()
                   && (path.toString().endsWith(".xml") || path.toString().endsWith(".xml.vm"));
             })) {
-      return stream.collect(Collectors.toUnmodifiableSet());
+      return stream.collect(toUnmodifiableSet());
     }
   }
 
@@ -85,7 +86,7 @@ public final class XdocUtil {
             (path, attr) -> {
               return attr.isRegularFile() && path.toString().endsWith(".xml.template");
             })) {
-      return stream.collect(Collectors.toUnmodifiableSet());
+      return stream.collect(toUnmodifiableSet());
     }
   }
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/meta/JavadocMetadataScraperTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/meta/JavadocMetadataScraperTest.java
@@ -31,7 +31,7 @@ import java.util.Map;
 import java.util.Map.Entry;
 import org.junit.jupiter.api.Test;
 
-public class JavadocMetadataScraperTest extends AbstractModuleTestSupport {
+final class JavadocMetadataScraperTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -39,7 +39,7 @@ public class JavadocMetadataScraperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAtclauseOrderCheck() throws Exception {
+  void atclauseOrderCheck() throws Exception {
     JavadocMetadataScraper.resetModuleDetailsStore();
     verifyWithInlineConfigParser(
         getPath("InputJavadocMetadataScraperAtclauseOrderCheck.java"),
@@ -50,7 +50,7 @@ public class JavadocMetadataScraperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationUseStyleCheck() throws Exception {
+  void annotationUseStyleCheck() throws Exception {
     JavadocMetadataScraper.resetModuleDetailsStore();
     verifyWithInlineConfigParser(
         getPath("InputJavadocMetadataScraperAnnotationUseStyleCheck.java"),
@@ -61,7 +61,7 @@ public class JavadocMetadataScraperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testBeforeExecutionExclusionFileFilter() throws Exception {
+  void beforeExecutionExclusionFileFilter() throws Exception {
     JavadocMetadataScraper.resetModuleDetailsStore();
     verifyWithInlineConfigParser(
         getPath("InputJavadocMetadataScraperBeforeExecutionExclusionFileFilter.java"),
@@ -74,7 +74,7 @@ public class JavadocMetadataScraperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNoCodeInFileCheck() throws Exception {
+  void noCodeInFileCheck() throws Exception {
     JavadocMetadataScraper.resetModuleDetailsStore();
     verifyWithInlineConfigParser(
         getPath("InputJavadocMetadataScraperNoCodeInFileCheck.java"),
@@ -85,7 +85,7 @@ public class JavadocMetadataScraperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPropertyMisplacedDefaultValueCheck() {
+  void propertyMisplacedDefaultValueCheck() {
     JavadocMetadataScraper.resetModuleDetailsStore();
     final CheckstyleException exc =
         assertThrows(
@@ -101,7 +101,7 @@ public class JavadocMetadataScraperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPropertyMisplacedTypeCheck() {
+  void propertyMisplacedTypeCheck() {
     JavadocMetadataScraper.resetModuleDetailsStore();
     final CheckstyleException exc =
         assertThrows(
@@ -118,7 +118,7 @@ public class JavadocMetadataScraperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPropertyMissingDefaultValueCheck() {
+  void propertyMissingDefaultValueCheck() {
     JavadocMetadataScraper.resetModuleDetailsStore();
     final CheckstyleException exc =
         assertThrows(
@@ -135,7 +135,7 @@ public class JavadocMetadataScraperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPropertyMissingTypeCheck() {
+  void propertyMissingTypeCheck() {
     JavadocMetadataScraper.resetModuleDetailsStore();
     final CheckstyleException exc =
         assertThrows(
@@ -151,7 +151,7 @@ public class JavadocMetadataScraperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPropertyWithNoCodeTagCheck() throws Exception {
+  void propertyWithNoCodeTagCheck() throws Exception {
     JavadocMetadataScraper.resetModuleDetailsStore();
     verifyWithInlineConfigParser(
         getPath("InputJavadocMetadataScraperPropertyWithNoCodeTagCheck.java"),
@@ -163,7 +163,7 @@ public class JavadocMetadataScraperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRightCurlyCheck() throws Exception {
+  void rightCurlyCheck() throws Exception {
     JavadocMetadataScraper.resetModuleDetailsStore();
     verifyWithInlineConfigParser(
         getPath("InputJavadocMetadataScraperRightCurlyCheck.java"), CommonUtil.EMPTY_STRING_ARRAY);
@@ -173,7 +173,7 @@ public class JavadocMetadataScraperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSummaryJavadocCheck() throws Exception {
+  void summaryJavadocCheck() throws Exception {
     JavadocMetadataScraper.resetModuleDetailsStore();
     verifyWithInlineConfigParser(
         getPath("InputJavadocMetadataScraperSummaryJavadocCheck.java"),
@@ -184,7 +184,7 @@ public class JavadocMetadataScraperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSuppressWarningsFilter() throws Exception {
+  void suppressWarningsFilter() throws Exception {
     JavadocMetadataScraper.resetModuleDetailsStore();
     verifyWithInlineConfigParser(
         getPath("InputJavadocMetadataScraperSuppressWarningsFilter.java"),
@@ -195,7 +195,7 @@ public class JavadocMetadataScraperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testWriteTagCheck() throws Exception {
+  void writeTagCheck() throws Exception {
     JavadocMetadataScraper.resetModuleDetailsStore();
     verifyWithInlineConfigParser(
         getPath("InputJavadocMetadataScraperWriteTagCheck.java"), CommonUtil.EMPTY_STRING_ARRAY);
@@ -205,7 +205,7 @@ public class JavadocMetadataScraperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmptyDescription() throws Exception {
+  void emptyDescription() throws Exception {
     JavadocMetadataScraper.resetModuleDetailsStore();
 
     final String[] expected = {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/meta/MetadataGeneratorUtilTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/meta/MetadataGeneratorUtilTest.java
@@ -21,7 +21,9 @@ package com.puppycrawl.tools.checkstyle.meta;
 
 import static com.google.common.truth.Truth.assertWithMessage;
 import static com.puppycrawl.tools.checkstyle.meta.JavadocMetadataScraper.MSG_DESC_MISSING;
+import static java.util.stream.Collectors.toCollection;
 
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.internal.utils.CheckUtil;
 import java.nio.file.Files;
@@ -32,7 +34,6 @@ import java.util.LinkedHashSet;
 import java.util.Set;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import org.itsallcode.io.Capturable;
 import org.itsallcode.junit.sysextensions.SystemOutGuard;
@@ -40,10 +41,10 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 
 @ExtendWith(SystemOutGuard.class)
-public final class MetadataGeneratorUtilTest extends AbstractModuleTestSupport {
+final class MetadataGeneratorUtilTest extends AbstractModuleTestSupport {
 
   private final Set<String> modulesContainingNoMetadataFile =
-      Set.of(
+      ImmutableSet.of(
           "Checker",
           "TreeWalker",
           "JavadocMetadataScraper",
@@ -67,7 +68,7 @@ public final class MetadataGeneratorUtilTest extends AbstractModuleTestSupport {
    *     System.out} for error messages
    */
   @Test
-  public void testMetadataFilesGenerationAllFiles(@SystemOutGuard.SysOut Capturable systemOut)
+  void metadataFilesGenerationAllFiles(@SystemOutGuard.SysOut Capturable systemOut)
       throws Exception {
     systemOut.captureMuted();
 
@@ -117,12 +118,12 @@ public final class MetadataGeneratorUtilTest extends AbstractModuleTestSupport {
               .filter(path -> !path.toString().endsWith(".properties"))
               .map(MetadataGeneratorUtilTest::getMetaFileName)
               .sorted()
-              .collect(Collectors.toCollection(LinkedHashSet::new));
+              .collect(toCollection(LinkedHashSet::new));
     }
     final Set<String> checkstyleModules =
         CheckUtil.getSimpleNames(CheckUtil.getCheckstyleModules()).stream()
             .sorted()
-            .collect(Collectors.toCollection(LinkedHashSet::new));
+            .collect(toCollection(LinkedHashSet::new));
     checkstyleModules.removeAll(modulesContainingNoMetadataFile);
     assertWithMessage(
             "Number of generated metadata files dont match with " + "number of checkstyle module")
--- a/src/test/java/com/puppycrawl/tools/checkstyle/meta/XmlMetaReaderTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/meta/XmlMetaReaderTest.java
@@ -29,7 +29,7 @@ import java.util.List;
 import org.apache.commons.io.IOUtils;
 import org.junit.jupiter.api.Test;
 
-public class XmlMetaReaderTest extends AbstractPathTestSupport {
+final class XmlMetaReaderTest extends AbstractPathTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -37,12 +37,12 @@ public class XmlMetaReaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void test() {
+  void test() {
     assertThat(XmlMetaReader.readAllModulesIncludingThirdPartyIfAny()).hasSize(200);
   }
 
   @Test
-  public void testDuplicatePackage() {
+  void duplicatePackage() {
     assertThat(
             XmlMetaReader.readAllModulesIncludingThirdPartyIfAny(
                 "com.puppycrawl.tools.checkstyle.meta"))
@@ -50,12 +50,12 @@ public class XmlMetaReaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testBadPackage() {
+  void badPackage() {
     assertThat(XmlMetaReader.readAllModulesIncludingThirdPartyIfAny("DOES.NOT.EXIST")).hasSize(200);
   }
 
   @Test
-  public void testReadXmlMetaCheckWithProperties() throws Exception {
+  void readXmlMetaCheckWithProperties() throws Exception {
     final String path = getPath("InputXmlMetaReaderCheckWithProps.xml");
     try (InputStream is = Files.newInputStream(Paths.get(path))) {
       final ModuleDetails result = XmlMetaReader.read(is, ModuleType.CHECK);
@@ -87,7 +87,7 @@ public class XmlMetaReaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testReadXmlMetaCheckNoProperties() throws Exception {
+  void readXmlMetaCheckNoProperties() throws Exception {
     final String path = getPath("InputXmlMetaReaderCheckNoProps.xml");
     try (InputStream is = Files.newInputStream(Paths.get(path))) {
       final ModuleDetails result = XmlMetaReader.read(is, ModuleType.CHECK);
@@ -107,7 +107,7 @@ public class XmlMetaReaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testReadXmlMetaFilter() throws Exception {
+  void readXmlMetaFilter() throws Exception {
     final String path = getPath("InputXmlMetaReaderFilter.xml");
     try (InputStream is = Files.newInputStream(Paths.get(path))) {
       final ModuleDetails result = XmlMetaReader.read(is, ModuleType.FILTER);
@@ -133,7 +133,7 @@ public class XmlMetaReaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testReadXmlMetaFileFilter() throws Exception {
+  void readXmlMetaFileFilter() throws Exception {
     final String path = getPath("InputXmlMetaReaderFileFilter.xml");
     try (InputStream is = Files.newInputStream(Paths.get(path))) {
       final ModuleDetails result = XmlMetaReader.read(is, ModuleType.FILEFILTER);
@@ -158,7 +158,7 @@ public class XmlMetaReaderTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testReadXmlMetaModuleTypeNull() throws Exception {
+  void readXmlMetaModuleTypeNull() throws Exception {
     try (InputStream is = IOUtils.toInputStream("", "UTF-8")) {
       assertThat(XmlMetaReader.read(is, null)).isNull();
     }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/utils/AnnotationUtilTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/utils/AnnotationUtilTest.java
@@ -23,6 +23,7 @@ import static com.google.common.truth.Truth.assertWithMessage;
 import static com.puppycrawl.tools.checkstyle.checks.annotation.SuppressWarningsCheck.MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED;
 import static com.puppycrawl.tools.checkstyle.internal.utils.TestUtil.isUtilsClassHasPrivateConstructor;
 
+import com.google.common.collect.ImmutableSet;
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.DetailAstImpl;
 import com.puppycrawl.tools.checkstyle.api.DetailAST;
@@ -31,7 +32,7 @@ import com.puppycrawl.tools.checkstyle.checks.annotation.SuppressWarningsCheck;
 import java.util.Set;
 import org.junit.jupiter.api.Test;
 
-public class AnnotationUtilTest extends AbstractModuleTestSupport {
+final class AnnotationUtilTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -39,7 +40,7 @@ public class AnnotationUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIsProperUtilsClass() {
+  void isProperUtilsClass() {
     try {
       isUtilsClassHasPrivateConstructor(AnnotationUtil.class);
       assertWithMessage("Exception is expected").fail();
@@ -53,7 +54,7 @@ public class AnnotationUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testContainsAnnotationNull() {
+  void containsAnnotationNull() {
     try {
       AnnotationUtil.containsAnnotation(null);
       assertWithMessage("IllegalArgumentException is expected").fail();
@@ -65,7 +66,7 @@ public class AnnotationUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testContainsAnnotationNull2() {
+  void containsAnnotationNull2() {
     try {
       AnnotationUtil.containsAnnotation(null, "");
       assertWithMessage("IllegalArgumentException is expected").fail();
@@ -77,7 +78,7 @@ public class AnnotationUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testContainsAnnotationFalse() {
+  void containsAnnotationFalse() {
     final DetailAstImpl ast = new DetailAstImpl();
     ast.setType(1);
     assertWithMessage("AnnotationUtil should not contain " + ast)
@@ -86,7 +87,7 @@ public class AnnotationUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testContainsAnnotationFalse2() {
+  void containsAnnotationFalse2() {
     final DetailAstImpl ast = new DetailAstImpl();
     ast.setType(1);
     final DetailAstImpl ast2 = new DetailAstImpl();
@@ -98,7 +99,7 @@ public class AnnotationUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testContainsAnnotationTrue() {
+  void containsAnnotationTrue() {
     final DetailAstImpl ast = new DetailAstImpl();
     ast.setType(1);
     final DetailAstImpl ast2 = new DetailAstImpl();
@@ -113,7 +114,7 @@ public class AnnotationUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationHolderNull() {
+  void annotationHolderNull() {
     try {
       AnnotationUtil.getAnnotationHolder(null);
       assertWithMessage("IllegalArgumentException is expected").fail();
@@ -125,7 +126,7 @@ public class AnnotationUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationNull() {
+  void annotationNull() {
     try {
       AnnotationUtil.getAnnotation(null, null);
       assertWithMessage("IllegalArgumentException is expected").fail();
@@ -137,7 +138,7 @@ public class AnnotationUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationNull2() {
+  void annotationNull2() {
     try {
       AnnotationUtil.getAnnotation(new DetailAstImpl(), null);
       assertWithMessage("IllegalArgumentException is expected").fail();
@@ -149,7 +150,7 @@ public class AnnotationUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAnnotationEmpty() {
+  void annotationEmpty() {
     try {
       AnnotationUtil.getAnnotation(new DetailAstImpl(), "");
       assertWithMessage("IllegalArgumentException is expected").fail();
@@ -161,7 +162,7 @@ public class AnnotationUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testContainsAnnotationWithNull() {
+  void containsAnnotationWithNull() {
     try {
       AnnotationUtil.getAnnotation(null, "");
       assertWithMessage("IllegalArgumentException is expected").fail();
@@ -173,9 +174,9 @@ public class AnnotationUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testContainsAnnotationListWithNullAst() {
+  void containsAnnotationListWithNullAst() {
     try {
-      AnnotationUtil.containsAnnotation(null, Set.of("Override"));
+      AnnotationUtil.containsAnnotation(null, ImmutableSet.of("Override"));
       assertWithMessage("IllegalArgumentException is expected").fail();
     } catch (IllegalArgumentException ex) {
       assertWithMessage("Invalid exception message")
@@ -185,7 +186,7 @@ public class AnnotationUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testContainsAnnotationListWithNullList() {
+  void containsAnnotationListWithNullList() {
     final DetailAST ast = new DetailAstImpl();
     final Set<String> annotations = null;
     try {
@@ -199,26 +200,26 @@ public class AnnotationUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testContainsAnnotationListWithEmptyList() {
+  void containsAnnotationListWithEmptyList() {
     final DetailAST ast = new DetailAstImpl();
-    final Set<String> annotations = Set.of();
+    final Set<String> annotations = ImmutableSet.of();
     final boolean result = AnnotationUtil.containsAnnotation(ast, annotations);
     assertWithMessage("An empty set should lead to a false result").that(result).isFalse();
   }
 
   @Test
-  public void testContainsAnnotationListWithNoAnnotationNode() {
+  void containsAnnotationListWithNoAnnotationNode() {
     final DetailAstImpl ast = new DetailAstImpl();
     final DetailAstImpl modifiersAst = new DetailAstImpl();
     modifiersAst.setType(TokenTypes.MODIFIERS);
     ast.addChild(modifiersAst);
-    final Set<String> annotations = Set.of("Override");
+    final Set<String> annotations = ImmutableSet.of("Override");
     final boolean result = AnnotationUtil.containsAnnotation(ast, annotations);
     assertWithMessage("An empty ast should lead to a false result").that(result).isFalse();
   }
 
   @Test
-  public void testContainsAnnotationListWithNoMatchingAnnotation() {
+  void containsAnnotationListWithNoMatchingAnnotation() {
     final DetailAstImpl ast = new DetailAstImpl();
     final DetailAstImpl modifiersAst =
         create(
@@ -227,13 +228,13 @@ public class AnnotationUtilTest extends AbstractModuleTestSupport {
                 TokenTypes.ANNOTATION,
                 create(TokenTypes.DOT, create(TokenTypes.IDENT, "Override"))));
     ast.addChild(modifiersAst);
-    final Set<String> annotations = Set.of("Deprecated");
+    final Set<String> annotations = ImmutableSet.of("Deprecated");
     final boolean result = AnnotationUtil.containsAnnotation(ast, annotations);
     assertWithMessage("No matching annotation found").that(result).isFalse();
   }
 
   @Test
-  public void testContainsAnnotation() {
+  void containsAnnotation() {
     final DetailAstImpl astForTest = new DetailAstImpl();
     astForTest.setType(TokenTypes.PACKAGE_DEF);
     final DetailAstImpl child = new DetailAstImpl();
@@ -258,7 +259,7 @@ public class AnnotationUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testContainsAnnotationWithStringFalse() {
+  void containsAnnotationWithStringFalse() {
     final DetailAstImpl astForTest = new DetailAstImpl();
     astForTest.setType(TokenTypes.PACKAGE_DEF);
     final DetailAstImpl child = new DetailAstImpl();
@@ -283,7 +284,7 @@ public class AnnotationUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testContainsAnnotationWithComment() {
+  void containsAnnotationWithComment() {
     final DetailAstImpl astForTest = new DetailAstImpl();
     astForTest.setType(TokenTypes.PACKAGE_DEF);
     final DetailAstImpl child = new DetailAstImpl();
@@ -311,7 +312,7 @@ public class AnnotationUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCompactNoUnchecked() throws Exception {
+  void compactNoUnchecked() throws Exception {
 
     final String[] expected = {
       "16:20: "
@@ -335,7 +336,7 @@ public class AnnotationUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testValuePairAnnotation() throws Exception {
+  void valuePairAnnotation() throws Exception {
 
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/utils/BlockCommentPositionTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/utils/BlockCommentPositionTest.java
@@ -19,6 +19,7 @@
 
 package com.puppycrawl.tools.checkstyle.utils;
 
+import static com.google.common.base.Preconditions.checkState;
 import static com.google.common.truth.Truth.assertWithMessage;
 
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
@@ -32,17 +33,17 @@ import java.util.List;
 import java.util.function.Function;
 import org.junit.jupiter.api.Test;
 
-public class BlockCommentPositionTest extends AbstractModuleTestSupport {
+final class BlockCommentPositionTest extends AbstractModuleTestSupport {
 
   @Test
-  public void testPrivateConstr() throws Exception {
+  void privateConstr() throws Exception {
     assertWithMessage("Constructor is not private")
         .that(TestUtil.isUtilsClassHasPrivateConstructor(BlockCommentPosition.class))
         .isTrue();
   }
 
   @Test
-  public void testJavaDocsRecognition() throws Exception {
+  void javaDocsRecognition() throws Exception {
     final List<BlockCommentPositionTestMetadata> metadataList =
         Arrays.asList(
             new BlockCommentPositionTestMetadata(
@@ -88,7 +89,7 @@ public class BlockCommentPositionTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavaDocsRecognitionNonCompilable() throws Exception {
+  void javaDocsRecognitionNonCompilable() throws Exception {
     final List<BlockCommentPositionTestMetadata> metadataList =
         Arrays.asList(
             new BlockCommentPositionTestMetadata(
@@ -113,9 +114,7 @@ public class BlockCommentPositionTest extends AbstractModuleTestSupport {
     DetailAST node = detailAST;
     while (node != null) {
       if (node.getType() == TokenTypes.BLOCK_COMMENT_BEGIN && JavadocUtil.isJavadocComment(node)) {
-        if (!assertion.apply(node)) {
-          throw new IllegalStateException("Position of comment is defined correctly");
-        }
+        checkState(assertion.apply(node), "Position of comment is defined correctly");
         matchFound++;
       }
       matchFound += getJavadocsCount(node.getFirstChild(), assertion);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/utils/ChainedPropertyUtilTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/utils/ChainedPropertyUtilTest.java
@@ -33,7 +33,7 @@ import java.nio.file.Files;
 import java.util.Properties;
 import org.junit.jupiter.api.Test;
 
-public class ChainedPropertyUtilTest extends AbstractModuleTestSupport {
+final class ChainedPropertyUtilTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -41,14 +41,14 @@ public class ChainedPropertyUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIsProperUtilsClass() throws ReflectiveOperationException {
+  void isProperUtilsClass() throws ReflectiveOperationException {
     assertWithMessage("Constructor is not private.")
         .that(isUtilsClassHasPrivateConstructor(ChainedPropertyUtil.class))
         .isTrue();
   }
 
   @Test
-  public void testPropertyChaining() throws Exception {
+  void propertyChaining() throws Exception {
     final File propertiesFile = new File(getPath("InputChainedPropertyUtil.properties"));
     final Properties properties = loadProperties(propertiesFile);
     final Properties resolvedProperties = ChainedPropertyUtil.getResolvedProperties(properties);
@@ -72,7 +72,7 @@ public class ChainedPropertyUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPropertyChainingPropertyNotFound() throws Exception {
+  void propertyChainingPropertyNotFound() throws Exception {
     final File propertiesFile =
         new File(getPath("InputChainedPropertyUtilUndefinedProperty.properties"));
     final Properties properties = loadProperties(propertiesFile);
@@ -87,7 +87,7 @@ public class ChainedPropertyUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPropertyChainingRecursiveUnresolvable() throws Exception {
+  void propertyChainingRecursiveUnresolvable() throws Exception {
     final File propertiesFile =
         new File(getPath("InputChainedPropertyUtilRecursiveUnresolvable.properties"));
     final Properties properties = loadProperties(propertiesFile);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/utils/CheckUtilTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/utils/CheckUtilTest.java
@@ -55,20 +55,20 @@ public class CheckUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIsProperUtilsClass() throws ReflectiveOperationException {
+  void isProperUtilsClass() throws ReflectiveOperationException {
     assertWithMessage("Constructor is not private")
         .that(isUtilsClassHasPrivateConstructor(CheckUtil.class))
         .isTrue();
   }
 
   @Test
-  public void testParseDoubleWithIncorrectToken() {
+  void parseDoubleWithIncorrectToken() {
     final double parsedDouble = CheckUtil.parseDouble("1_02", TokenTypes.ASSIGN);
     assertWithMessage("Invalid parse result").that(parsedDouble).isEqualTo(Double.NaN);
   }
 
   @Test
-  public void testEquals() {
+  void testEquals() {
     final DetailAstImpl litStatic = new DetailAstImpl();
     litStatic.setType(TokenTypes.LITERAL_STATIC);
 
@@ -112,7 +112,7 @@ public class CheckUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAccessModifierFromModifiersTokenWrongTokenType() {
+  void getAccessModifierFromModifiersTokenWrongTokenType() {
     final DetailAstImpl modifiers = new DetailAstImpl();
     modifiers.setType(TokenTypes.METHOD_DEF);
 
@@ -129,7 +129,7 @@ public class CheckUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetTypeParameterNames() throws Exception {
+  void getTypeParameterNames() throws Exception {
     final DetailAST parameterizedClassNode = getNodeFromFile(TokenTypes.CLASS_DEF);
     final List<String> expected = Arrays.asList("V", "C");
     final List<String> actual = CheckUtil.getTypeParameterNames(parameterizedClassNode);
@@ -138,7 +138,7 @@ public class CheckUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetTypeParameters() throws Exception {
+  void getTypeParameters() throws Exception {
     final DetailAST parameterizedClassNode = getNodeFromFile(TokenTypes.CLASS_DEF);
     final DetailAST firstTypeParameter = getNode(parameterizedClassNode, TokenTypes.TYPE_PARAMETER);
     final List<DetailAST> expected =
@@ -149,7 +149,7 @@ public class CheckUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIsEqualsMethod() throws Exception {
+  void isEqualsMethod() throws Exception {
     final DetailAST equalsMethodNode = getNodeFromFile(TokenTypes.METHOD_DEF);
     final DetailAST someOtherMethod = equalsMethodNode.getNextSibling();
 
@@ -162,7 +162,7 @@ public class CheckUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIsNonVoidMethod() throws Exception {
+  void isNonVoidMethod() throws Exception {
     final DetailAST nonVoidMethod = getNodeFromFile(TokenTypes.METHOD_DEF);
     final DetailAST voidMethod = nonVoidMethod.getNextSibling();
 
@@ -175,7 +175,7 @@ public class CheckUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetAccessModifierFromModifiersToken() throws Exception {
+  void getAccessModifierFromModifiersToken() throws Exception {
     final DetailAST interfaceDef = getNodeFromFile(TokenTypes.INTERFACE_DEF);
     final AccessModifierOption modifierInterface =
         CheckUtil.getAccessModifierFromModifiersToken(
@@ -214,7 +214,7 @@ public class CheckUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetFirstNode() throws Exception {
+  void getFirstNode() throws Exception {
     final DetailAST classDef = getNodeFromFile(TokenTypes.CLASS_DEF);
 
     final DetailAST firstChild = classDef.getFirstChild().getFirstChild();
@@ -223,7 +223,7 @@ public class CheckUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetFirstNode1() {
+  void getFirstNode1() {
     final DetailAstImpl child = new DetailAstImpl();
     child.setLineNo(5);
     child.setColumnNo(6);
@@ -239,7 +239,7 @@ public class CheckUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testGetFirstNode2() {
+  void getFirstNode2() {
     final DetailAstImpl child = new DetailAstImpl();
     child.setLineNo(6);
     child.setColumnNo(5);
@@ -255,7 +255,7 @@ public class CheckUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testParseDoubleFloatingPointValues() {
+  void parseDoubleFloatingPointValues() {
     assertWithMessage("Invalid parse result")
         .that(CheckUtil.parseDouble("-0.05f", TokenTypes.NUM_FLOAT))
         .isEqualTo(-0.05);
@@ -277,7 +277,7 @@ public class CheckUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testParseDoubleIntegerValues() {
+  void parseDoubleIntegerValues() {
     assertWithMessage("Invalid parse result")
         .that(CheckUtil.parseDouble("0L", TokenTypes.NUM_LONG))
         .isEqualTo(0.0);
@@ -314,7 +314,7 @@ public class CheckUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testParseClassNames() {
+  void parseClassNames() {
     final Set<String> actual =
         CheckUtil.parseClassNames("I.am.class.name.with.dot.in.the.end.", "ClassOnly", "my.Class");
     final Set<String> expected = new HashSet<>();
@@ -326,7 +326,7 @@ public class CheckUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEqualsAvoidNullCheck() throws Exception {
+  void equalsAvoidNullCheck() throws Exception {
 
     final String[] expected = {
       "14:28: " + getCheckMessage(EqualsAvoidNullCheck.class, MSG_EQUALS_AVOID_NULL),
@@ -336,7 +336,7 @@ public class CheckUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMultipleVariableDeclarationsCheck() throws Exception {
+  void multipleVariableDeclarationsCheck() throws Exception {
     final String[] expected = {
       "11:5: " + getCheckMessage(MultipleVariableDeclarationsCheck.class, MSG_MULTIPLE),
       "14:5: " + getCheckMessage(MultipleVariableDeclarationsCheck.class, MSG_MULTIPLE),
@@ -345,7 +345,7 @@ public class CheckUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNestedIfDepth() throws Exception {
+  void nestedIfDepth() throws Exception {
     final String[] expected = {
       "26:17: " + getCheckMessage(NestedIfDepthCheck.class, MSG_KEY, 2, 1),
       "52:17: " + getCheckMessage(NestedIfDepthCheck.class, MSG_KEY, 2, 1),
@@ -354,13 +354,13 @@ public class CheckUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavaDocMethod() throws Exception {
+  void javaDocMethod() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
     verifyWithInlineConfigParser(getPath("InputCheckUtil4.java"), expected);
   }
 
   @Test
-  public void testJavaDocMethod2() throws Exception {
+  void javaDocMethod2() throws Exception {
     final String[] expected = {
       "14:25: " + getCheckMessage(JavadocMethodCheck.class, MSG_EXPECTED_TAG, "@param", "i"),
     };
@@ -368,7 +368,7 @@ public class CheckUtilTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testJavadoc() throws Exception {
+  void javadoc() throws Exception {
     final String[] expected = {
       "25:39: " + getCheckMessage(JavadocMethodCheck.class, MSG_EXPECTED_TAG, "@param", "i"),
     };
@@ -402,6 +402,6 @@ public class CheckUtilTest extends AbstractModuleTestSupport {
         .that(node.isPresent())
         .isTrue();
 
-    return node.get();
+    return node.orElseThrow();
   }
 }
--- a/src/test/java/com/puppycrawl/tools/checkstyle/utils/CodePointUtilTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/utils/CodePointUtilTest.java
@@ -24,10 +24,10 @@ import static com.puppycrawl.tools.checkstyle.internal.utils.TestUtil.isUtilsCla
 
 import org.junit.jupiter.api.Test;
 
-public class CodePointUtilTest {
+final class CodePointUtilTest {
 
   @Test
-  public void testIsProperUtilsClass() throws ReflectiveOperationException {
+  void isProperUtilsClass() throws ReflectiveOperationException {
     assertWithMessage("Constructor is not private")
         .that(isUtilsClassHasPrivateConstructor(CodePointUtil.class))
         .isTrue();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/utils/CommonUtilTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/utils/CommonUtilTest.java
@@ -22,6 +22,8 @@ package com.puppycrawl.tools.checkstyle.utils;
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.common.truth.Truth.assertWithMessage;
 import static com.puppycrawl.tools.checkstyle.internal.utils.TestUtil.isUtilsClassHasPrivateConstructor;
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static java.util.regex.Pattern.MULTILINE;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.mockito.Mockito.CALLS_REAL_METHODS;
 import static org.mockito.Mockito.mock;
@@ -40,7 +42,6 @@ import java.lang.reflect.Constructor;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.net.URL;
-import java.nio.charset.StandardCharsets;
 import java.util.Dictionary;
 import java.util.Properties;
 import java.util.regex.Pattern;
@@ -48,7 +49,7 @@ import org.apache.commons.io.IOUtils;
 import org.junit.jupiter.api.Test;
 import org.mockito.MockedStatic;
 
-public class CommonUtilTest extends AbstractPathTestSupport {
+final class CommonUtilTest extends AbstractPathTestSupport {
 
   /** After appending to path produces equivalent, but denormalized path. */
   private static final String PATH_DENORMALIZER = "/levelDown/.././";
@@ -59,7 +60,7 @@ public class CommonUtilTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testIsProperUtilsClass() throws ReflectiveOperationException {
+  void isProperUtilsClass() throws ReflectiveOperationException {
     assertWithMessage("Constructor is not private")
         .that(isUtilsClassHasPrivateConstructor(CommonUtil.class))
         .isTrue();
@@ -67,7 +68,7 @@ public class CommonUtilTest extends AbstractPathTestSupport {
 
   /** Test CommonUtil.countCharInString. */
   @Test
-  public void testLengthExpandedTabs() {
+  void lengthExpandedTabs() {
     final String s1 = "\t";
     assertWithMessage("Invalid expanded tabs length")
         .that(CommonUtil.lengthExpandedTabs(s1, s1.length(), 8))
@@ -103,7 +104,7 @@ public class CommonUtilTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testCreatePattern() {
+  void createPattern() {
     assertWithMessage("invalid pattern")
         .that(CommonUtil.createPattern("Test").pattern())
         .isEqualTo("Test");
@@ -113,7 +114,7 @@ public class CommonUtilTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testBadRegex() {
+  void badRegex() {
     final IllegalArgumentException ex =
         assertThrows(
             IllegalArgumentException.class,
@@ -127,12 +128,12 @@ public class CommonUtilTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testBadRegex2() {
+  void badRegex2() {
     final IllegalArgumentException ex =
         assertThrows(
             IllegalArgumentException.class,
             () -> {
-              CommonUtil.createPattern("[", Pattern.MULTILINE);
+              CommonUtil.createPattern("[", MULTILINE);
             });
     assertWithMessage("Invalid exception message")
         .that(ex)
@@ -141,7 +142,7 @@ public class CommonUtilTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testFileExtensions() {
+  void fileExtensions() {
     final String[] fileExtensions = {"java"};
     final File pdfFile = new File("file.pdf");
     assertWithMessage("Invalid file extension")
@@ -174,42 +175,42 @@ public class CommonUtilTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testHasWhitespaceBefore() {
+  void hasWhitespaceBefore() {
     assertWithMessage("Invalid result").that(CommonUtil.hasWhitespaceBefore(0, "a")).isTrue();
     assertWithMessage("Invalid result").that(CommonUtil.hasWhitespaceBefore(4, "    a")).isTrue();
     assertWithMessage("Invalid result").that(CommonUtil.hasWhitespaceBefore(5, "    a")).isFalse();
   }
 
   @Test
-  public void testBaseClassNameForCanonicalName() {
+  void baseClassNameForCanonicalName() {
     assertWithMessage("Invalid base class name")
         .that(CommonUtil.baseClassName("java.util.List"))
         .isEqualTo("List");
   }
 
   @Test
-  public void testBaseClassNameForSimpleName() {
+  void baseClassNameForSimpleName() {
     assertWithMessage("Invalid base class name")
         .that(CommonUtil.baseClassName("Set"))
         .isEqualTo("Set");
   }
 
   @Test
-  public void testRelativeNormalizedPath() {
+  void relativeNormalizedPath() {
     final String relativePath = CommonUtil.relativizePath("/home", "/home/test");
 
     assertWithMessage("Invalid relative path").that(relativePath).isEqualTo("test");
   }
 
   @Test
-  public void testRelativeNormalizedPathWithNullBaseDirectory() {
+  void relativeNormalizedPathWithNullBaseDirectory() {
     final String relativePath = CommonUtil.relativizePath(null, "/tmp");
 
     assertWithMessage("Invalid relative path").that(relativePath).isEqualTo("/tmp");
   }
 
   @Test
-  public void testRelativeNormalizedPathWithDenormalizedBaseDirectory() throws IOException {
+  void relativeNormalizedPathWithDenormalizedBaseDirectory() throws IOException {
     final String sampleAbsolutePath = new File("src/main/java").getCanonicalPath();
     final String absoluteFilePath = sampleAbsolutePath + "/SampleFile.java";
     final String basePath = sampleAbsolutePath + PATH_DENORMALIZER;
@@ -220,19 +221,19 @@ public class CommonUtilTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testPattern() {
+  void pattern() {
     final boolean result = CommonUtil.isPatternValid("someValidPattern");
     assertWithMessage("Should return true when pattern is valid").that(result).isTrue();
   }
 
   @Test
-  public void testInvalidPattern() {
+  void invalidPattern() {
     final boolean result = CommonUtil.isPatternValid("some[invalidPattern");
     assertWithMessage("Should return false when pattern is invalid").that(result).isFalse();
   }
 
   @Test
-  public void testGetExistingConstructor() throws NoSuchMethodException {
+  void getExistingConstructor() throws NoSuchMethodException {
     final Constructor<?> constructor = CommonUtil.getConstructor(String.class, String.class);
 
     assertWithMessage("Invalid constructor")
@@ -241,7 +242,7 @@ public class CommonUtilTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetNonExistentConstructor() {
+  void getNonExistentConstructor() {
     final IllegalStateException ex =
         assertThrows(
             IllegalStateException.class,
@@ -255,7 +256,7 @@ public class CommonUtilTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testInvokeConstructor() throws NoSuchMethodException {
+  void invokeConstructor() throws NoSuchMethodException {
     final Constructor<String> constructor = String.class.getConstructor(String.class);
 
     final String constructedString = CommonUtil.invokeConstructor(constructor, "string");
@@ -265,7 +266,7 @@ public class CommonUtilTest extends AbstractPathTestSupport {
 
   @SuppressWarnings("rawtypes")
   @Test
-  public void testInvokeConstructorThatFails() throws NoSuchMethodException {
+  void invokeConstructorThatFails() throws NoSuchMethodException {
     final Constructor<Dictionary> constructor = Dictionary.class.getConstructor();
     final IllegalStateException ex =
         assertThrows(
@@ -280,7 +281,7 @@ public class CommonUtilTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testClose() {
+  void close() {
     final TestCloseable closeable = new TestCloseable();
 
     CommonUtil.close(null);
@@ -290,7 +291,7 @@ public class CommonUtilTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testCloseWithException() {
+  void closeWithException() {
     final IllegalStateException ex =
         assertThrows(
             IllegalStateException.class,
@@ -307,7 +308,7 @@ public class CommonUtilTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testFillTemplateWithStringsByRegexp() {
+  void fillTemplateWithStringsByRegexp() {
     assertWithMessage("invalid result")
         .that(
             CommonUtil.fillTemplateWithStringsByRegexp(
@@ -328,7 +329,7 @@ public class CommonUtilTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetFileNameWithoutExtension() {
+  void getFileNameWithoutExtension() {
     assertWithMessage("invalid result")
         .that(CommonUtil.getFileNameWithoutExtension("filename"))
         .isEqualTo("filename");
@@ -341,7 +342,7 @@ public class CommonUtilTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetFileExtension() {
+  void getFileExtension() {
     assertWithMessage("Invalid extension")
         .that(CommonUtil.getFileExtension("filename"))
         .isEqualTo("");
@@ -354,133 +355,133 @@ public class CommonUtilTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testIsIdentifier() {
+  void isIdentifier() {
     assertWithMessage("Should return true when valid identifier is passed")
         .that(CommonUtil.isIdentifier("aValidIdentifier"))
         .isTrue();
   }
 
   @Test
-  public void testIsIdentifierEmptyString() {
+  void isIdentifierEmptyString() {
     assertWithMessage("Should return false when empty string is passed")
         .that(CommonUtil.isIdentifier(""))
         .isFalse();
   }
 
   @Test
-  public void testIsIdentifierInvalidFirstSymbol() {
+  void isIdentifierInvalidFirstSymbol() {
     assertWithMessage("Should return false when invalid identifier is passed")
         .that(CommonUtil.isIdentifier("1InvalidIdentifier"))
         .isFalse();
   }
 
   @Test
-  public void testIsIdentifierInvalidSymbols() {
+  void isIdentifierInvalidSymbols() {
     assertWithMessage("Should return false when invalid identifier is passed")
         .that(CommonUtil.isIdentifier("invalid#Identifier"))
         .isFalse();
   }
 
   @Test
-  public void testIsName() {
+  void isName() {
     assertWithMessage("Should return true when valid name is passed")
         .that(CommonUtil.isName("a.valid.Nam3"))
         .isTrue();
   }
 
   @Test
-  public void testIsNameEmptyString() {
+  void isNameEmptyString() {
     assertWithMessage("Should return false when empty string is passed")
         .that(CommonUtil.isName(""))
         .isFalse();
   }
 
   @Test
-  public void testIsNameInvalidFirstSymbol() {
+  void isNameInvalidFirstSymbol() {
     assertWithMessage("Should return false when invalid name is passed")
         .that(CommonUtil.isName("1.invalid.name"))
         .isFalse();
   }
 
   @Test
-  public void testIsNameEmptyPart() {
+  void isNameEmptyPart() {
     assertWithMessage("Should return false when name has empty part")
         .that(CommonUtil.isName("invalid..name"))
         .isFalse();
   }
 
   @Test
-  public void testIsNameEmptyLastPart() {
+  void isNameEmptyLastPart() {
     assertWithMessage("Should return false when name has empty part")
         .that(CommonUtil.isName("invalid.name."))
         .isFalse();
   }
 
   @Test
-  public void testIsNameInvalidSymbol() {
+  void isNameInvalidSymbol() {
     assertWithMessage("Should return false when invalid name is passed")
         .that(CommonUtil.isName("invalid.name#42"))
         .isFalse();
   }
 
   @Test
-  public void testIsBlank() {
+  void isBlank() {
     assertWithMessage("Should return false when string is not empty")
         .that(CommonUtil.isBlank("string"))
         .isFalse();
   }
 
   @Test
-  public void testIsBlankAheadWhitespace() {
+  void isBlankAheadWhitespace() {
     assertWithMessage("Should return false when string is not empty")
         .that(CommonUtil.isBlank("  string"))
         .isFalse();
   }
 
   @Test
-  public void testIsBlankBehindWhitespace() {
+  void isBlankBehindWhitespace() {
     assertWithMessage("Should return false when string is not empty")
         .that(CommonUtil.isBlank("string    "))
         .isFalse();
   }
 
   @Test
-  public void testIsBlankWithWhitespacesAround() {
+  void isBlankWithWhitespacesAround() {
     assertWithMessage("Should return false when string is not empty")
         .that(CommonUtil.isBlank("    string    "))
         .isFalse();
   }
 
   @Test
-  public void testIsBlankWhitespaceInside() {
+  void isBlankWhitespaceInside() {
     assertWithMessage("Should return false when string is not empty")
         .that(CommonUtil.isBlank("str    ing"))
         .isFalse();
   }
 
   @Test
-  public void testIsBlankNullString() {
+  void isBlankNullString() {
     assertWithMessage("Should return true when string is null")
         .that(CommonUtil.isBlank(null))
         .isTrue();
   }
 
   @Test
-  public void testIsBlankWithEmptyString() {
+  void isBlankWithEmptyString() {
     assertWithMessage("Should return true when string is empty")
         .that(CommonUtil.isBlank(""))
         .isTrue();
   }
 
   @Test
-  public void testIsBlankWithWhitespacesOnly() {
+  void isBlankWithWhitespacesOnly() {
     assertWithMessage("Should return true when string contains only spaces")
         .that(CommonUtil.isBlank("   "))
         .isTrue();
   }
 
   @Test
-  public void testGetUriByFilenameFindsAbsoluteResourceOnClasspath() throws Exception {
+  void getUriByFilenameFindsAbsoluteResourceOnClasspath() throws Exception {
     final String filename = "/" + getPackageLocation() + "/InputCommonUtilTest_empty_checks.xml";
     final URI uri = CommonUtil.getUriByFilename(filename);
 
@@ -491,7 +492,7 @@ public class CommonUtilTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetUriByFilenameFindsRelativeResourceOnClasspath() throws Exception {
+  void getUriByFilenameFindsRelativeResourceOnClasspath() throws Exception {
     final String filename = getPackageLocation() + "/InputCommonUtilTest_empty_checks.xml";
     final URI uri = CommonUtil.getUriByFilename(filename);
 
@@ -507,7 +508,7 @@ public class CommonUtilTest extends AbstractPathTestSupport {
    * interpreted relative to the current package "com/puppycrawl/tools/checkstyle/utils/"
    */
   @Test
-  public void testGetUriByFilenameFindsResourceRelativeToRootClasspath() throws Exception {
+  void getUriByFilenameFindsResourceRelativeToRootClasspath() throws Exception {
     final String filename = getPackageLocation() + "/InputCommonUtilTest_resource.txt";
     final URI uri = CommonUtil.getUriByFilename(filename);
     assertWithMessage("URI is null for: " + filename).that(uri).isNotNull();
@@ -518,12 +519,12 @@ public class CommonUtilTest extends AbstractPathTestSupport {
     assertWithMessage("URI is relative to package " + uriRelativeToPackage)
         .that(uri.toString())
         .doesNotContain(uriRelativeToPackage);
-    final String content = IOUtils.toString(uri.toURL(), StandardCharsets.UTF_8);
+    final String content = IOUtils.toString(uri.toURL(), UTF_8);
     assertWithMessage("Content mismatches for: " + uri).that(content).startsWith("good");
   }
 
   @Test
-  public void testGetUriByFilenameClasspathPrefixLoadConfig() throws Exception {
+  void getUriByFilenameClasspathPrefixLoadConfig() throws Exception {
     final String filename =
         CommonUtil.CLASSPATH_URL_PROTOCOL
             + getPackageLocation()
@@ -537,7 +538,7 @@ public class CommonUtilTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetUriByFilenameFindsRelativeResourceOnClasspathPrefix() throws Exception {
+  void getUriByFilenameFindsRelativeResourceOnClasspathPrefix() throws Exception {
     final String filename =
         CommonUtil.CLASSPATH_URL_PROTOCOL
             + getPackageLocation()
@@ -551,14 +552,14 @@ public class CommonUtilTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testIsCodePointWhitespace() {
+  void isCodePointWhitespace() {
     final int[] codePoints = " 123".codePoints().toArray();
     assertThat(CommonUtil.isCodePointWhitespace(codePoints, 0)).isTrue();
     assertThat(CommonUtil.isCodePointWhitespace(codePoints, 1)).isFalse();
   }
 
   @Test
-  public void testLoadSuppressionsUriSyntaxException() throws Exception {
+  void loadSuppressionsUriSyntaxException() throws Exception {
     final URL configUrl = mock();
     when(configUrl.toURI()).thenThrow(URISyntaxException.class);
     try (MockedStatic<CommonUtil> utilities = mockStatic(CommonUtil.class, CALLS_REAL_METHODS)) {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/utils/FilterUtilTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/utils/FilterUtilTest.java
@@ -26,19 +26,19 @@ import java.io.File;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
 
-public class FilterUtilTest {
+final class FilterUtilTest {
 
   @TempDir public File temporaryFolder;
 
   @Test
-  public void testIsProperUtilsClass() throws ReflectiveOperationException {
+  void isProperUtilsClass() throws ReflectiveOperationException {
     assertWithMessage("Constructor is not private")
         .that(isUtilsClassHasPrivateConstructor(FilterUtil.class))
         .isTrue();
   }
 
   @Test
-  public void testExistingFile() throws Exception {
+  void existingFile() throws Exception {
     final File file = File.createTempFile("junit", null, temporaryFolder);
     assertWithMessage("Suppression file exists")
         .that(FilterUtil.isFileExists(file.getPath()))
@@ -46,7 +46,7 @@ public class FilterUtilTest {
   }
 
   @Test
-  public void testNonExistentFile() {
+  void nonExistentFile() {
     assertWithMessage("Suppression file does not exist")
         .that(FilterUtil.isFileExists("non-existent.xml"))
         .isFalse();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/utils/JavadocUtilTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/utils/JavadocUtilTest.java
@@ -35,10 +35,10 @@ import com.puppycrawl.tools.checkstyle.checks.javadoc.JavadocTags;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class JavadocUtilTest {
+final class JavadocUtilTest {
 
   @Test
-  public void testTags() {
+  void tags() {
     final String[] text = {
       "/** @see elsewhere ",
       " * {@link List }, {@link List link text }",
@@ -51,7 +51,7 @@ public class JavadocUtilTest {
   }
 
   @Test
-  public void testBlockTag() {
+  void blockTag() {
     final String[] text = {
       "/** @see elsewhere ", " */",
     };
@@ -61,7 +61,7 @@ public class JavadocUtilTest {
   }
 
   @Test
-  public void testTagType() {
+  void tagType() {
     final String[] text = {
       "/** @see block", " * {@link List inline}, {@link List#add(Object)}",
     };
@@ -75,7 +75,7 @@ public class JavadocUtilTest {
   }
 
   @Test
-  public void testInlineTagLinkText() {
+  void inlineTagLinkText() {
     final String[] text = {
       "/** {@link List link text }",
     };
@@ -88,7 +88,7 @@ public class JavadocUtilTest {
   }
 
   @Test
-  public void testInlineTagMethodRef() {
+  void inlineTagMethodRef() {
     final String[] text = {
       "/** {@link List#add(Object)}",
     };
@@ -101,7 +101,7 @@ public class JavadocUtilTest {
   }
 
   @Test
-  public void testTagPositions() {
+  void tagPositions() {
     final String[] text = {
       "/** @see elsewhere", "    also {@link Name value} */",
     };
@@ -128,7 +128,7 @@ public class JavadocUtilTest {
   }
 
   @Test
-  public void testInlineTagPositions() {
+  void inlineTagPositions() {
     final String[] text = {"/** Also {@link Name value} */"};
     final Comment comment = new Comment(text, 1, 0, text[0].length());
 
@@ -143,7 +143,7 @@ public class JavadocUtilTest {
   }
 
   @Test
-  public void testInvalidTags() {
+  void invalidTags() {
     final String[] text = {
       "/** @fake block", " * {@bogus inline}", " * {@link List valid}",
     };
@@ -166,7 +166,7 @@ public class JavadocUtilTest {
   }
 
   @Test
-  public void testEmptyBlockComment() {
+  void emptyBlockComment() {
     final String emptyComment = "";
     assertWithMessage("Should return false when empty string is passed")
         .that(JavadocUtil.isJavadocComment(emptyComment))
@@ -174,7 +174,7 @@ public class JavadocUtilTest {
   }
 
   @Test
-  public void testEmptyBlockCommentAst() {
+  void emptyBlockCommentAst() {
     final DetailAstImpl commentBegin = new DetailAstImpl();
     commentBegin.setType(TokenTypes.BLOCK_COMMENT_BEGIN);
     commentBegin.setText("/*");
@@ -196,7 +196,7 @@ public class JavadocUtilTest {
   }
 
   @Test
-  public void testEmptyJavadocComment() {
+  void emptyJavadocComment() {
     final String emptyJavadocComment = "*";
     assertWithMessage("Should return true when empty javadoc comment is passed")
         .that(JavadocUtil.isJavadocComment(emptyJavadocComment))
@@ -204,7 +204,7 @@ public class JavadocUtilTest {
   }
 
   @Test
-  public void testEmptyJavadocCommentAst() {
+  void emptyJavadocCommentAst() {
     final DetailAstImpl commentBegin = new DetailAstImpl();
     commentBegin.setType(TokenTypes.BLOCK_COMMENT_BEGIN);
     commentBegin.setText("/*");
@@ -233,21 +233,21 @@ public class JavadocUtilTest {
   }
 
   @Test
-  public void testIsProperUtilsClass() throws ReflectiveOperationException {
+  void isProperUtilsClass() throws ReflectiveOperationException {
     assertWithMessage("Constructor is not private")
         .that(isUtilsClassHasPrivateConstructor(JavadocUtil.class))
         .isTrue();
   }
 
   @Test
-  public void testGetTokenNameForId() {
+  void getTokenNameForId() {
     assertWithMessage("Invalid token name")
         .that(JavadocUtil.getTokenName(JavadocTokenTypes.EOF))
         .isEqualTo("EOF");
   }
 
   @Test
-  public void testGetTokenNameForLargeId() {
+  void getTokenNameForLargeId() {
     try {
       JavadocUtil.getTokenName(30073);
       assertWithMessage("exception expected").fail();
@@ -259,7 +259,7 @@ public class JavadocUtilTest {
   }
 
   @Test
-  public void testGetTokenNameForInvalidId() {
+  void getTokenNameForInvalidId() {
     try {
       JavadocUtil.getTokenName(110);
       assertWithMessage("exception expected").fail();
@@ -271,7 +271,7 @@ public class JavadocUtilTest {
   }
 
   @Test
-  public void testGetTokenNameForLowerBoundInvalidId() {
+  void getTokenNameForLowerBoundInvalidId() {
     try {
       JavadocUtil.getTokenName(10095);
       assertWithMessage("exception expected").fail();
@@ -283,7 +283,7 @@ public class JavadocUtilTest {
   }
 
   @Test
-  public void testGetTokenIdThatIsUnknown() {
+  void getTokenIdThatIsUnknown() {
     try {
       JavadocUtil.getTokenId("");
       assertWithMessage("exception expected").fail();
@@ -295,14 +295,14 @@ public class JavadocUtilTest {
   }
 
   @Test
-  public void testGetTokenId() {
+  void getTokenId() {
     final int tokenId = JavadocUtil.getTokenId("JAVADOC");
 
     assertWithMessage("Invalid token id").that(tokenId).isEqualTo(JavadocTokenTypes.JAVADOC);
   }
 
   @Test
-  public void testGetJavadocCommentContent() {
+  void getJavadocCommentContent() {
     final DetailAstImpl detailAST = new DetailAstImpl();
     final DetailAstImpl javadoc = new DetailAstImpl();
 
@@ -314,7 +314,7 @@ public class JavadocUtilTest {
   }
 
   @Test
-  public void testGetFirstToken() {
+  void getFirstToken() {
     final JavadocNodeImpl javadocNode = new JavadocNodeImpl();
     final JavadocNodeImpl basetag = new JavadocNodeImpl();
     basetag.setType(JavadocTokenTypes.BASE_TAG);
@@ -331,7 +331,7 @@ public class JavadocUtilTest {
   }
 
   @Test
-  public void testGetPreviousSibling() {
+  void getPreviousSibling() {
     final JavadocNodeImpl root = new JavadocNodeImpl();
 
     final JavadocNodeImpl node = new JavadocNodeImpl();
@@ -350,14 +350,14 @@ public class JavadocUtilTest {
   }
 
   @Test
-  public void testGetLastTokenName() {
+  void getLastTokenName() {
     assertWithMessage("Unexpected token name")
         .that(JavadocUtil.getTokenName(10094))
         .isEqualTo("RP");
   }
 
   @Test
-  public void testEscapeAllControlChars() {
+  void escapeAllControlChars() {
     assertWithMessage("invalid result")
         .that(JavadocUtil.escapeAllControlChars("abc"))
         .isEqualTo("abc");
--- a/src/test/java/com/puppycrawl/tools/checkstyle/utils/ModuleReflectionUtilTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/utils/ModuleReflectionUtilTest.java
@@ -39,17 +39,17 @@ import java.io.File;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 
-public class ModuleReflectionUtilTest {
+final class ModuleReflectionUtilTest {
 
   @Test
-  public void testIsProperUtilsClass() throws ReflectiveOperationException {
+  void isProperUtilsClass() throws ReflectiveOperationException {
     assertWithMessage("Constructor is not private")
         .that(isUtilsClassHasPrivateConstructor(ModuleReflectionUtil.class))
         .isTrue();
   }
 
   @Test
-  public void testIsCheckstyleModule() {
+  void isCheckstyleModule() {
     assertWithMessage("Should return true when checkstyle module is passed")
         .that(ModuleReflectionUtil.isCheckstyleModule(CheckClass.class))
         .isTrue();
@@ -74,7 +74,7 @@ public class ModuleReflectionUtilTest {
   }
 
   @Test
-  public void testIsValidCheckstyleClass() {
+  void isValidCheckstyleClass() {
     assertWithMessage("Should return true when valid checkstyle class is passed")
         .that(ModuleReflectionUtil.isCheckstyleModule(ValidCheckstyleClass.class))
         .isTrue();
@@ -93,7 +93,7 @@ public class ModuleReflectionUtilTest {
   }
 
   @Test
-  public void testIsCheckstyleCheck() {
+  void isCheckstyleCheck() {
     assertWithMessage("Should return true when valid checkstyle check is passed")
         .that(ModuleReflectionUtil.isCheckstyleTreeWalkerCheck(CheckClass.class))
         .isTrue();
@@ -103,7 +103,7 @@ public class ModuleReflectionUtilTest {
   }
 
   @Test
-  public void testIsFileSetModule() {
+  void isFileSetModule() {
     assertWithMessage("Should return true when valid checkstyle file set module is passed")
         .that(ModuleReflectionUtil.isFileSetModule(FileSetModuleClass.class))
         .isTrue();
@@ -113,7 +113,7 @@ public class ModuleReflectionUtilTest {
   }
 
   @Test
-  public void testIsFilterModule() {
+  void isFilterModule() {
     assertWithMessage("Should return true when valid checkstyle filter module is passed")
         .that(ModuleReflectionUtil.isFilterModule(FilterClass.class))
         .isTrue();
@@ -123,7 +123,7 @@ public class ModuleReflectionUtilTest {
   }
 
   @Test
-  public void testIsFileFilterModule() {
+  void isFileFilterModule() {
     assertWithMessage("Should return true when valid checkstyle file filter module is passed")
         .that(ModuleReflectionUtil.isFileFilterModule(FileFilterModuleClass.class))
         .isTrue();
@@ -133,7 +133,7 @@ public class ModuleReflectionUtilTest {
   }
 
   @Test
-  public void testIsTreeWalkerFilterModule() {
+  void isTreeWalkerFilterModule() {
     assertWithMessage("Should return true when valid checkstyle TreeWalker filter module is passed")
         .that(ModuleReflectionUtil.isTreeWalkerFilterModule(TreeWalkerFilterClass.class))
         .isTrue();
@@ -143,7 +143,7 @@ public class ModuleReflectionUtilTest {
   }
 
   @Test
-  public void testIsAuditListener() {
+  void isAuditListener() {
     assertWithMessage("Should return true when valid checkstyle AuditListener module is passed")
         .that(ModuleReflectionUtil.isAuditListener(DefaultLogger.class))
         .isTrue();
@@ -153,7 +153,7 @@ public class ModuleReflectionUtilTest {
   }
 
   @Test
-  public void testIsRootModule() {
+  void isRootModule() {
     assertWithMessage("Should return true when valid checkstyle root module is passed")
         .that(ModuleReflectionUtil.isRootModule(RootModuleClass.class))
         .isTrue();
@@ -163,7 +163,7 @@ public class ModuleReflectionUtilTest {
   }
 
   @Test
-  public void testKeepEclipseHappy() {
+  void keepEclipseHappy() {
     final InvalidNonDefaultConstructorClass test = new InvalidNonDefaultConstructorClass(0);
     assertWithMessage("should use constructor").that(test).isNotNull();
     assertWithMessage("should use field").that(test.getField()).isEqualTo(1);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/utils/ParserUtilTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/utils/ParserUtilTest.java
@@ -26,17 +26,17 @@ import com.puppycrawl.tools.checkstyle.api.DetailAST;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class ParserUtilTest {
+final class ParserUtilTest {
 
   @Test
-  public void testIsProperUtilsClass() throws ReflectiveOperationException {
+  void isProperUtilsClass() throws ReflectiveOperationException {
     assertWithMessage("Constructor is not private")
         .that(isUtilsClassHasPrivateConstructor(ParserUtil.class))
         .isTrue();
   }
 
   @Test
-  public void testCreationOfFakeCommentBlock() {
+  void creationOfFakeCommentBlock() {
     final DetailAST testCommentBlock = ParserUtil.createBlockCommentNode("test_comment");
     assertWithMessage("Invalid token type")
         .that(testCommentBlock.getType())
--- a/src/test/java/com/puppycrawl/tools/checkstyle/utils/ScopeUtilTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/utils/ScopeUtilTest.java
@@ -28,17 +28,17 @@ import com.puppycrawl.tools.checkstyle.api.Scope;
 import com.puppycrawl.tools.checkstyle.api.TokenTypes;
 import org.junit.jupiter.api.Test;
 
-public class ScopeUtilTest {
+final class ScopeUtilTest {
 
   @Test
-  public void testIsProperUtilsClass() throws ReflectiveOperationException {
+  void isProperUtilsClass() throws ReflectiveOperationException {
     assertWithMessage("Constructor is not private")
         .that(isUtilsClassHasPrivateConstructor(ScopeUtil.class))
         .isTrue();
   }
 
   @Test
-  public void testInClassBlock() {
+  void inClassBlock() {
     assertWithMessage("Should return false when passed is not class")
         .that(ScopeUtil.isInClassBlock(new DetailAstImpl()))
         .isFalse();
@@ -76,7 +76,7 @@ public class ScopeUtilTest {
   }
 
   @Test
-  public void testInEnumBlock() {
+  void inEnumBlock() {
     assertWithMessage("Should return false when passed is not enum")
         .that(ScopeUtil.isInEnumBlock(new DetailAstImpl()))
         .isFalse();
@@ -114,7 +114,7 @@ public class ScopeUtilTest {
   }
 
   @Test
-  public void testIsInCodeBlock() {
+  void isInCodeBlock() {
     assertWithMessage("invalid result")
         .that(ScopeUtil.isInCodeBlock(getNode(TokenTypes.CLASS_DEF)))
         .isFalse();
@@ -139,7 +139,7 @@ public class ScopeUtilTest {
   }
 
   @Test
-  public void testInRecordBlock() {
+  void inRecordBlock() {
     assertWithMessage("Should return false when passed is not record")
         .that(ScopeUtil.isInRecordBlock(new DetailAstImpl()))
         .isFalse();
@@ -177,42 +177,42 @@ public class ScopeUtilTest {
   }
 
   @Test
-  public void testIsOuterMostTypeInterface() {
+  void isOuterMostTypeInterface() {
     assertWithMessage("Should return false when passed is not outer most type")
         .that(ScopeUtil.isOuterMostType(getNode(TokenTypes.INTERFACE_DEF, TokenTypes.MODIFIERS)))
         .isFalse();
   }
 
   @Test
-  public void testIsOuterMostTypeAnnotation() {
+  void isOuterMostTypeAnnotation() {
     assertWithMessage("Should return false when passed is not outer most type")
         .that(ScopeUtil.isOuterMostType(getNode(TokenTypes.ANNOTATION_DEF, TokenTypes.MODIFIERS)))
         .isFalse();
   }
 
   @Test
-  public void testIsOuterMostTypeEnum() {
+  void isOuterMostTypeEnum() {
     assertWithMessage("Should return false when passed is not outer most type")
         .that(ScopeUtil.isOuterMostType(getNode(TokenTypes.ENUM_DEF, TokenTypes.MODIFIERS)))
         .isFalse();
   }
 
   @Test
-  public void testIsOuterMostTypeClass() {
+  void isOuterMostTypeClass() {
     assertWithMessage("Should return false when passed is not outer most type")
         .that(ScopeUtil.isOuterMostType(getNode(TokenTypes.CLASS_DEF, TokenTypes.MODIFIERS)))
         .isFalse();
   }
 
   @Test
-  public void testIsOuterMostTypePackageDef() {
+  void isOuterMostTypePackageDef() {
     assertWithMessage("Should return false when passed is not outer most type")
         .that(ScopeUtil.isOuterMostType(getNode(TokenTypes.PACKAGE_DEF, TokenTypes.DOT)))
         .isTrue();
   }
 
   @Test
-  public void testIsLocalVariableDefCatch() {
+  void isLocalVariableDefCatch() {
     assertWithMessage("Should return true when passed is variable def")
         .that(
             ScopeUtil.isLocalVariableDef(
@@ -221,7 +221,7 @@ public class ScopeUtilTest {
   }
 
   @Test
-  public void testIsLocalVariableDefUnexpected() {
+  void isLocalVariableDefUnexpected() {
     assertWithMessage("Should return false when passed is not variable def")
         .that(ScopeUtil.isLocalVariableDef(getNode(TokenTypes.LITERAL_CATCH)))
         .isFalse();
@@ -231,7 +231,7 @@ public class ScopeUtilTest {
   }
 
   @Test
-  public void testIsLocalVariableDefResource() {
+  void isLocalVariableDefResource() {
     final DetailAstImpl node = getNode(TokenTypes.RESOURCE);
     final DetailAstImpl modifiers = new DetailAstImpl();
     modifiers.setType(TokenTypes.MODIFIERS);
@@ -251,7 +251,7 @@ public class ScopeUtilTest {
   }
 
   @Test
-  public void testIsLocalVariableDefVariable() {
+  void isLocalVariableDefVariable() {
     assertWithMessage("invalid result")
         .that(ScopeUtil.isLocalVariableDef(getNode(TokenTypes.SLIST, TokenTypes.VARIABLE_DEF)))
         .isTrue();
@@ -269,7 +269,7 @@ public class ScopeUtilTest {
   }
 
   @Test
-  public void testIsClassFieldDef() {
+  void isClassFieldDef() {
     assertWithMessage("Should return true when passed is class field def")
         .that(
             ScopeUtil.isClassFieldDef(
@@ -286,7 +286,7 @@ public class ScopeUtilTest {
   }
 
   @Test
-  public void testSurroundingScope() {
+  void surroundingScope() {
     final Scope publicScope =
         ScopeUtil.getSurroundingScope(
             getNodeWithParentScope(TokenTypes.LITERAL_PUBLIC, "public", TokenTypes.ANNOTATION_DEF));
@@ -307,7 +307,7 @@ public class ScopeUtilTest {
   }
 
   @Test
-  public void testIsInScope() {
+  void isInScope() {
     assertWithMessage("Should return true when node is in valid scope")
         .that(
             ScopeUtil.isInScope(
@@ -325,14 +325,14 @@ public class ScopeUtilTest {
   }
 
   @Test
-  public void testSurroundingScopeOfNodeChildOfLiteralNewIsAnoninner() {
+  void surroundingScopeOfNodeChildOfLiteralNewIsAnoninner() {
     final Scope scope =
         ScopeUtil.getSurroundingScope(getNode(TokenTypes.LITERAL_NEW, TokenTypes.IDENT));
     assertWithMessage("Invalid surrounding scope").that(scope).isEqualTo(Scope.ANONINNER);
   }
 
   @Test
-  public void testIsInInterfaceBlock() {
+  void isInInterfaceBlock() {
     final DetailAST ast =
         getNode(
             TokenTypes.INTERFACE_DEF,
@@ -349,7 +349,7 @@ public class ScopeUtilTest {
   }
 
   @Test
-  public void testIsInAnnotationBlock() {
+  void isInAnnotationBlock() {
     final DetailAST ast =
         getNode(
             TokenTypes.ANNOTATION_DEF,
@@ -366,7 +366,7 @@ public class ScopeUtilTest {
   }
 
   @Test
-  public void testisInInterfaceOrAnnotationBlock() {
+  void isInInterfaceOrAnnotationBlock() {
     assertWithMessage("Should return true when node is in interface or annotation block")
         .that(
             ScopeUtil.isInInterfaceOrAnnotationBlock(
--- a/src/test/java/com/puppycrawl/tools/checkstyle/utils/TokenUtilTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/utils/TokenUtilTest.java
@@ -34,17 +34,17 @@ import java.util.Optional;
 import java.util.TreeMap;
 import org.junit.jupiter.api.Test;
 
-public class TokenUtilTest {
+final class TokenUtilTest {
 
   @Test
-  public void testIsProperUtilsClass() throws ReflectiveOperationException {
+  void isProperUtilsClass() throws ReflectiveOperationException {
     assertWithMessage("Constructor is not private")
         .that(isUtilsClassHasPrivateConstructor(TokenUtil.class))
         .isTrue();
   }
 
   @Test
-  public void testGetIntFromAccessibleField() throws NoSuchFieldException {
+  void getIntFromAccessibleField() throws NoSuchFieldException {
     final Field field = Integer.class.getField("MAX_VALUE");
     final int maxValue = TokenUtil.getIntFromField(field, 0);
 
@@ -52,7 +52,7 @@ public class TokenUtilTest {
   }
 
   @Test
-  public void testGetIntFromInaccessibleField() throws NoSuchFieldException {
+  void getIntFromInaccessibleField() throws NoSuchFieldException {
     final Field field = Integer.class.getDeclaredField("value");
 
     try {
@@ -72,7 +72,7 @@ public class TokenUtilTest {
   }
 
   @Test
-  public void testNameToValueMapFromPublicIntFields() {
+  void nameToValueMapFromPublicIntFields() {
     final Map<String, Integer> actualMap =
         TokenUtil.nameToValueMapFromPublicIntFields(Integer.class);
     final Map<String, Integer> expectedMap = new TreeMap<>();
@@ -85,7 +85,7 @@ public class TokenUtilTest {
   }
 
   @Test
-  public void testInvertMap() {
+  void invertMap() {
     final Map<String, Integer> map = new TreeMap<>();
     map.put("ZERO", 0);
     map.put("ONE", 1);
@@ -103,7 +103,7 @@ public class TokenUtilTest {
   }
 
   @Test
-  public void testTokenValueIncorrect() throws IllegalAccessException {
+  void tokenValueIncorrect() throws IllegalAccessException {
     int maxId = 0;
     final Field[] fields = TokenTypes.class.getDeclaredFields();
     for (final Field field : fields) {
@@ -131,7 +131,7 @@ public class TokenUtilTest {
   }
 
   @Test
-  public void testTokenValueCorrect() throws IllegalAccessException {
+  void tokenValueCorrect() throws IllegalAccessException {
     final Field[] fields = TokenTypes.class.getDeclaredFields();
     for (final Field field : fields) {
       // Only process the int declarations.
@@ -147,7 +147,7 @@ public class TokenUtilTest {
   }
 
   @Test
-  public void testTokenValueIncorrect2() {
+  void tokenValueIncorrect2() {
     final int id = 0;
     try {
       TokenUtil.getTokenName(id);
@@ -160,7 +160,7 @@ public class TokenUtilTest {
   }
 
   @Test
-  public void testTokenIdIncorrect() {
+  void tokenIdIncorrect() {
     final String id = "NON_EXISTENT_VALUE";
     try {
       TokenUtil.getTokenId(id);
@@ -173,7 +173,7 @@ public class TokenUtilTest {
   }
 
   @Test
-  public void testShortDescriptionIncorrect() {
+  void shortDescriptionIncorrect() {
     final String id = "NON_EXISTENT_VALUE";
     try {
       TokenUtil.getShortDescription(id);
@@ -186,7 +186,7 @@ public class TokenUtilTest {
   }
 
   @Test
-  public void testIsCommentType() {
+  void isCommentType() {
     assertWithMessage("Should return true when valid type passed")
         .that(TokenUtil.isCommentType(TokenTypes.SINGLE_LINE_COMMENT))
         .isTrue();
@@ -211,14 +211,14 @@ public class TokenUtilTest {
   }
 
   @Test
-  public void testGetTokenTypesTotalNumber() {
+  void getTokenTypesTotalNumber() {
     final int tokenTypesTotalNumber = TokenUtil.getTokenTypesTotalNumber();
 
     assertWithMessage("Invalid token total number").that(tokenTypesTotalNumber).isEqualTo(194);
   }
 
   @Test
-  public void testGetAllTokenIds() {
+  void getAllTokenIds() {
     final int[] allTokenIds = TokenUtil.getAllTokenIds();
     final int sum = Arrays.stream(allTokenIds).sum();
 
@@ -227,7 +227,7 @@ public class TokenUtilTest {
   }
 
   @Test
-  public void testGetTokenNameWithGreatestPossibleId() {
+  void getTokenNameWithGreatestPossibleId() {
     final int id = TokenTypes.COMMENT_CONTENT;
     final String tokenName = TokenUtil.getTokenName(id);
 
@@ -235,7 +235,7 @@ public class TokenUtilTest {
   }
 
   @Test
-  public void testCorrectBehaviourOfGetTokenId() {
+  void correctBehaviourOfGetTokenId() {
     final String id = "COMPILATION_UNIT";
 
     assertWithMessage("Invalid token id")
@@ -244,7 +244,7 @@ public class TokenUtilTest {
   }
 
   @Test
-  public void testCorrectBehaviourOfShortDescription() {
+  void correctBehaviourOfShortDescription() {
     final String id = "COMPILATION_UNIT";
     final String shortDescription = TokenUtil.getShortDescription(id);
 
@@ -254,7 +254,7 @@ public class TokenUtilTest {
   }
 
   @Test
-  public void testFindFirstTokenByPredicate() {
+  void findFirstTokenByPredicate() {
     final DetailAstImpl astForTest = new DetailAstImpl();
     final DetailAstImpl child = new DetailAstImpl();
     final DetailAstImpl firstSibling = new DetailAstImpl();
@@ -274,7 +274,7 @@ public class TokenUtilTest {
   }
 
   @Test
-  public void testForEachChild() {
+  void forEachChild() {
     final DetailAstImpl astForTest = new DetailAstImpl();
     final DetailAstImpl child = new DetailAstImpl();
     final DetailAstImpl firstSibling = new DetailAstImpl();
@@ -296,7 +296,7 @@ public class TokenUtilTest {
   }
 
   @Test
-  public void testIsTypeDeclaration() {
+  void isTypeDeclaration() {
     assertWithMessage("Should return true when valid type passed")
         .that(TokenUtil.isTypeDeclaration(TokenTypes.CLASS_DEF))
         .isTrue();
@@ -315,7 +315,7 @@ public class TokenUtilTest {
   }
 
   @Test
-  public void testIsOfTypeTrue() {
+  void isOfTypeTrue() {
     final int type = TokenTypes.LITERAL_CATCH;
     final DetailAstImpl astForTest = new DetailAstImpl();
     astForTest.setType(type);
@@ -331,7 +331,7 @@ public class TokenUtilTest {
   }
 
   @Test
-  public void testIsOfTypeFalse() {
+  void isOfTypeFalse() {
     final int type = TokenTypes.LITERAL_CATCH;
     final DetailAstImpl astForTest1 = new DetailAstImpl();
     final DetailAstImpl astForTest2 = null;
@@ -352,7 +352,7 @@ public class TokenUtilTest {
   }
 
   @Test
-  public void testIsBooleanLiteralType() {
+  void isBooleanLiteralType() {
     assertWithMessage("Result is not expected")
         .that(TokenUtil.isBooleanLiteralType(TokenTypes.LITERAL_TRUE))
         .isTrue();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/utils/XpathUtilTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/utils/XpathUtilTest.java
@@ -23,6 +23,7 @@ import static com.google.common.truth.Truth.assertWithMessage;
 import static com.puppycrawl.tools.checkstyle.AbstractPathTestSupport.addEndOfLine;
 import static com.puppycrawl.tools.checkstyle.internal.utils.TestUtil.isUtilsClassHasPrivateConstructor;
 import static com.puppycrawl.tools.checkstyle.utils.XpathUtil.getTextAttributeValue;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.puppycrawl.tools.checkstyle.DetailAstImpl;
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
@@ -32,25 +33,24 @@ import com.puppycrawl.tools.checkstyle.xpath.AbstractNode;
 import com.puppycrawl.tools.checkstyle.xpath.RootNode;
 import java.io.File;
 import java.io.IOException;
-import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.util.List;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
 
-public class XpathUtilTest {
+final class XpathUtilTest {
 
   @TempDir public File tempFolder;
 
   @Test
-  public void testIsProperUtilsClass() throws ReflectiveOperationException {
+  void isProperUtilsClass() throws ReflectiveOperationException {
     assertWithMessage("Constructor is not private")
         .that(isUtilsClassHasPrivateConstructor(XpathUtil.class))
         .isTrue();
   }
 
   @Test
-  public void testSupportsTextAttribute() {
+  void supportsTextAttribute() {
     assertWithMessage("Should return true for supported token types")
         .that(XpathUtil.supportsTextAttribute(createDetailAST(TokenTypes.IDENT)))
         .isTrue();
@@ -78,7 +78,7 @@ public class XpathUtilTest {
   }
 
   @Test
-  public void testGetValue() {
+  void getValue() {
     assertWithMessage("Returned value differs from expected")
         .that(getTextAttributeValue(createDetailAST(TokenTypes.STRING_LITERAL, "\"HELLO WORLD\"")))
         .isEqualTo("HELLO WORLD");
@@ -94,10 +94,10 @@ public class XpathUtilTest {
   }
 
   @Test
-  public void testPrintXpathNotComment() throws Exception {
+  void printXpathNotComment() throws Exception {
     final String fileContent = "class Test { public void method() {int a = 5;}}";
     final File file = File.createTempFile("junit", null, tempFolder);
-    Files.write(file.toPath(), fileContent.getBytes(StandardCharsets.UTF_8));
+    Files.write(file.toPath(), fileContent.getBytes(UTF_8));
     final String expected =
         addEndOfLine(
             "COMPILATION_UNIT -> COMPILATION_UNIT [1:0]",
@@ -113,10 +113,10 @@ public class XpathUtilTest {
   }
 
   @Test
-  public void testPrintXpathComment() throws Exception {
+  void printXpathComment() throws Exception {
     final String fileContent = "class Test { /* comment */ }";
     final File file = File.createTempFile("junit", null, tempFolder);
-    Files.write(file.toPath(), fileContent.getBytes(StandardCharsets.UTF_8));
+    Files.write(file.toPath(), fileContent.getBytes(UTF_8));
     final String expected =
         addEndOfLine(
             "COMPILATION_UNIT -> COMPILATION_UNIT [1:0]",
@@ -128,10 +128,10 @@ public class XpathUtilTest {
   }
 
   @Test
-  public void testPrintXpathTwo() throws Exception {
+  void printXpathTwo() throws Exception {
     final String fileContent = "class Test { public void method() {int a = 5; int b = 5;}}";
     final File file = File.createTempFile("junit", null, tempFolder);
-    Files.write(file.toPath(), fileContent.getBytes(StandardCharsets.UTF_8));
+    Files.write(file.toPath(), fileContent.getBytes(UTF_8));
     final String expected =
         addEndOfLine(
             "COMPILATION_UNIT -> COMPILATION_UNIT [1:0]",
@@ -155,10 +155,10 @@ public class XpathUtilTest {
   }
 
   @Test
-  public void testInvalidXpath() throws IOException {
+  void invalidXpath() throws IOException {
     final String fileContent = "class Test { public void method() {int a = 5; int b = 5;}}";
     final File file = File.createTempFile("junit", null, tempFolder);
-    Files.write(file.toPath(), fileContent.getBytes(StandardCharsets.UTF_8));
+    Files.write(file.toPath(), fileContent.getBytes(UTF_8));
     final String invalidXpath = "\\//CLASS_DEF" + "//METHOD_DEF//VARIABLE_DEF//IDENT";
     try {
       XpathUtil.printXpathBranch(invalidXpath, file);
@@ -176,7 +176,7 @@ public class XpathUtilTest {
   }
 
   @Test
-  public void testCreateChildren() {
+  void createChildren() {
     final DetailAstImpl rootAst = new DetailAstImpl();
     final DetailAstImpl elementAst = new DetailAstImpl();
     rootAst.addChild(elementAst);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/xpath/AttributeNodeTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/xpath/AttributeNodeTest.java
@@ -28,31 +28,31 @@ import net.sf.saxon.tree.iter.AxisIterator;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-public class AttributeNodeTest {
+final class AttributeNodeTest {
 
   private static AttributeNode attributeNode;
 
   @BeforeEach
-  public void init() {
+  void init() {
     attributeNode = new AttributeNode("name", "value");
   }
 
   @Test
-  public void testGetNamespaceUri() {
+  void getNamespaceUri() {
     assertWithMessage("Attribute node should have default namespace URI")
         .that(attributeNode.getNamespaceUri())
         .isEqualTo(NamespaceUri.NULL);
   }
 
   @Test
-  public void testGetUri() {
+  void getUri() {
     assertWithMessage("Attribute node should have blank URI")
         .that(attributeNode.getURI())
         .isEqualTo("");
   }
 
   @Test
-  public void testCompareOrder() {
+  void compareOrder() {
     try {
       attributeNode.compareOrder(null);
       assertWithMessage("Exception is excepted").fail();
@@ -64,7 +64,7 @@ public class AttributeNodeTest {
   }
 
   @Test
-  public void testGetDepth() {
+  void getDepth() {
     final UnsupportedOperationException exception =
         assertThrows(UnsupportedOperationException.class, attributeNode::getDepth);
     assertWithMessage("Invalid exception message")
@@ -74,14 +74,14 @@ public class AttributeNodeTest {
   }
 
   @Test
-  public void testHasChildNodes() {
+  void hasChildNodes() {
     assertWithMessage("Attribute node shouldn't have children")
         .that(attributeNode.hasChildNodes())
         .isFalse();
   }
 
   @Test
-  public void testGetAttributeValue() {
+  void getAttributeValue() {
     try {
       attributeNode.getAttributeValue("", "");
       assertWithMessage("Exception is excepted").fail();
@@ -93,7 +93,7 @@ public class AttributeNodeTest {
   }
 
   @Test
-  public void testGetChildren() {
+  void getChildren() {
     final UnsupportedOperationException exception =
         assertThrows(UnsupportedOperationException.class, attributeNode::getChildren);
     assertWithMessage("Invalid exception message")
@@ -103,7 +103,7 @@ public class AttributeNodeTest {
   }
 
   @Test
-  public void testGetParent() {
+  void getParent() {
     try {
       attributeNode.getParent();
       assertWithMessage("Exception is excepted").fail();
@@ -115,7 +115,7 @@ public class AttributeNodeTest {
   }
 
   @Test
-  public void testGetRoot() {
+  void getRoot() {
     try {
       attributeNode.getRoot();
       assertWithMessage("Exception is excepted").fail();
@@ -127,14 +127,14 @@ public class AttributeNodeTest {
   }
 
   @Test
-  public void testGetStringValue() {
+  void getStringValue() {
     assertWithMessage("Invalid string value")
         .that(attributeNode.getStringValue())
         .isEqualTo("value");
   }
 
   @Test
-  public void testIterate() {
+  void iterate() {
     try (AxisIterator ignored = attributeNode.iterateAxis(AxisInfo.SELF)) {
       assertWithMessage("Exception is excepted").fail();
     } catch (UnsupportedOperationException ex) {
@@ -145,7 +145,7 @@ public class AttributeNodeTest {
   }
 
   @Test
-  public void testGetLineNumber() {
+  void getLineNumber() {
     try {
       attributeNode.getLineNumber();
       assertWithMessage("Exception is excepted").fail();
@@ -157,7 +157,7 @@ public class AttributeNodeTest {
   }
 
   @Test
-  public void testGetColumnNumber() {
+  void getColumnNumber() {
     try {
       attributeNode.getColumnNumber();
       assertWithMessage("Exception is excepted").fail();
@@ -169,7 +169,7 @@ public class AttributeNodeTest {
   }
 
   @Test
-  public void testGetTokenType() {
+  void getTokenType() {
     try {
       attributeNode.getTokenType();
       assertWithMessage("Exception is excepted").fail();
@@ -181,7 +181,7 @@ public class AttributeNodeTest {
   }
 
   @Test
-  public void testGetUnderlyingNode() {
+  void getUnderlyingNode() {
     try {
       attributeNode.getUnderlyingNode();
       assertWithMessage("Exception is excepted").fail();
@@ -193,7 +193,7 @@ public class AttributeNodeTest {
   }
 
   @Test
-  public void testGetAllNamespaces() {
+  void getAllNamespaces() {
     try {
       attributeNode.getAllNamespaces();
       assertWithMessage("Exception is excepted").fail();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/xpath/ElementNodeTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/xpath/ElementNodeTest.java
@@ -39,7 +39,7 @@ import net.sf.saxon.tree.iter.EmptyIterator;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-public class ElementNodeTest extends AbstractPathTestSupport {
+final class ElementNodeTest extends AbstractPathTestSupport {
 
   private static RootNode rootNode;
 
@@ -49,14 +49,14 @@ public class ElementNodeTest extends AbstractPathTestSupport {
   }
 
   @BeforeEach
-  public void init() throws Exception {
+  void init() throws Exception {
     final File file = new File(getPath("InputXpathMapperAst.java"));
     final DetailAST rootAst = JavaParser.parseFile(file, JavaParser.Options.WITHOUT_COMMENTS);
     rootNode = new RootNode(rootAst);
   }
 
   @Test
-  public void testParentChildOrdering() {
+  void parentChildOrdering() {
     final DetailAstImpl detailAST = new DetailAstImpl();
     detailAST.setType(TokenTypes.VARIABLE_DEF);
 
@@ -75,7 +75,7 @@ public class ElementNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testSiblingsOrdering() {
+  void siblingsOrdering() {
     final DetailAstImpl detailAst1 = new DetailAstImpl();
     detailAst1.setType(TokenTypes.VARIABLE_DEF);
 
@@ -99,7 +99,7 @@ public class ElementNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testCompareOrderWrongInstance() throws Exception {
+  void compareOrderWrongInstance() throws Exception {
     final String xpath = "//OBJBLOCK";
     final List<NodeInfo> nodes = getXpathItems(xpath, rootNode);
     final int result = nodes.get(0).compareOrder(null);
@@ -107,7 +107,7 @@ public class ElementNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetParent() throws Exception {
+  void getParent() throws Exception {
     final String xpath = "//OBJBLOCK";
     final List<NodeInfo> nodes = getXpathItems(xpath, rootNode);
     assertWithMessage("Invalid number of nodes").that(nodes).hasSize(1);
@@ -118,7 +118,7 @@ public class ElementNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testRootOfElementNode() throws Exception {
+  void rootOfElementNode() throws Exception {
     final String xpath = "//OBJBLOCK";
     final List<NodeInfo> nodes = getXpathItems(xpath, rootNode);
     assertWithMessage("Invalid number of nodes").that(nodes).hasSize(1);
@@ -132,7 +132,7 @@ public class ElementNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetNodeByValueNumInt() throws Exception {
+  void getNodeByValueNumInt() throws Exception {
     final String xPath = "//NUM_INT[@text = 123]";
     final List<NodeInfo> nodes = getXpathItems(xPath, rootNode);
     assertWithMessage("Invalid number of nodes").that(nodes).hasSize(1);
@@ -141,7 +141,7 @@ public class ElementNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetNodeByValueStringLiteral() throws Exception {
+  void getNodeByValueStringLiteral() throws Exception {
     final String xPath = "//STRING_LITERAL[@text = 'HelloWorld']";
     final List<NodeInfo> nodes = getXpathItems(xPath, rootNode);
     assertWithMessage("Invalid number of nodes").that(nodes).hasSize(2);
@@ -150,14 +150,14 @@ public class ElementNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetNodeByValueWithSameTokenText() throws Exception {
+  void getNodeByValueWithSameTokenText() throws Exception {
     final String xPath = "//MODIFIERS[@text = 'MODIFIERS']";
     final List<NodeInfo> nodes = getXpathItems(xPath, rootNode);
     assertWithMessage("Invalid number of nodes").that(nodes).hasSize(0);
   }
 
   @Test
-  public void testGetAttributeValue() {
+  void getAttributeValue() {
     final DetailAstImpl detailAST = new DetailAstImpl();
     detailAST.setType(TokenTypes.IDENT);
     detailAST.setText("HelloWorld");
@@ -170,7 +170,7 @@ public class ElementNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetAttributeCached() {
+  void getAttributeCached() {
     final DetailAstImpl detailAST = new DetailAstImpl();
     detailAST.setType(TokenTypes.IDENT);
     detailAST.setText("HelloWorld");
@@ -185,7 +185,7 @@ public class ElementNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetAttributeValueNoAttribute() {
+  void getAttributeValueNoAttribute() {
     final DetailAstImpl detailAST = new DetailAstImpl();
     detailAST.setType(TokenTypes.CLASS_DEF);
     detailAST.setText("HelloWorld");
@@ -198,7 +198,7 @@ public class ElementNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetAttributeValueWrongAttribute() {
+  void getAttributeValueWrongAttribute() {
     final DetailAstImpl detailAST = new DetailAstImpl();
     detailAST.setType(TokenTypes.IDENT);
     detailAST.setText("HelloWorld");
@@ -211,7 +211,7 @@ public class ElementNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testIterateAxisEmptyChildren() {
+  void iterateAxisEmptyChildren() {
     final DetailAstImpl detailAST = new DetailAstImpl();
     detailAST.setType(TokenTypes.METHOD_DEF);
     final ElementNode elementNode = new ElementNode(rootNode, rootNode, detailAST, 1, 0);
@@ -224,7 +224,7 @@ public class ElementNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testIterateAxisWithChildren() {
+  void iterateAxisWithChildren() {
     final DetailAstImpl detailAST = new DetailAstImpl();
     detailAST.setType(TokenTypes.METHOD_DEF);
     final DetailAstImpl childAst = new DetailAstImpl();
@@ -240,7 +240,7 @@ public class ElementNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testIterateAxisWithNoSiblings() {
+  void iterateAxisWithNoSiblings() {
     final DetailAstImpl detailAST = new DetailAstImpl();
     detailAST.setType(TokenTypes.VARIABLE_DEF);
 
--- a/src/test/java/com/puppycrawl/tools/checkstyle/xpath/RootNodeTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/xpath/RootNodeTest.java
@@ -36,7 +36,7 @@ import net.sf.saxon.tree.iter.EmptyIterator;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-public class RootNodeTest extends AbstractPathTestSupport {
+final class RootNodeTest extends AbstractPathTestSupport {
 
   private static RootNode rootNode;
 
@@ -46,14 +46,14 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @BeforeEach
-  public void init() throws Exception {
+  void init() throws Exception {
     final File file = new File(getPath("InputXpathMapperAst.java"));
     final DetailAST rootAst = JavaParser.parseFile(file, JavaParser.Options.WITHOUT_COMMENTS);
     rootNode = new RootNode(rootAst);
   }
 
   @Test
-  public void testCompareOrder() {
+  void compareOrder() {
     try {
       rootNode.compareOrder(null);
       assertWithMessage("Exception is excepted").fail();
@@ -65,7 +65,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testXpath() throws Exception {
+  void xpath() throws Exception {
     final String xpath = "/";
     final List<NodeInfo> nodes = getXpathItems(xpath, rootNode);
     assertWithMessage("Invalid number of nodes").that(nodes).hasSize(1);
@@ -79,24 +79,24 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetDepth() {
+  void getDepth() {
     assertWithMessage("Root node depth should be 0").that(rootNode.getDepth()).isEqualTo(0);
   }
 
   @Test
-  public void testGetTokenType() {
+  void getTokenType() {
     assertWithMessage("Invalid token type")
         .that(rootNode.getTokenType())
         .isEqualTo(TokenTypes.COMPILATION_UNIT);
   }
 
   @Test
-  public void testGetLineNumber() {
+  void getLineNumber() {
     assertWithMessage("Invalid line number").that(rootNode.getLineNumber()).isEqualTo(1);
   }
 
   @Test
-  public void testGetColumnNumber() {
+  void getColumnNumber() {
     assertWithMessage("Invalid column number").that(rootNode.getColumnNumber()).isEqualTo(0);
   }
 
@@ -106,7 +106,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
    * Test exists until https://github.com/checkstyle/checkstyle/issues/4997
    */
   @Test
-  public void testNonRealGetColumnNumber() {
+  void nonRealGetColumnNumber() {
     final DetailAstImpl nonRealNode = new DetailAstImpl();
     nonRealNode.setType(TokenTypes.PACKAGE_DEF);
     nonRealNode.setLineNo(555);
@@ -119,12 +119,12 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetLocalPart() {
+  void getLocalPart() {
     assertWithMessage("Invalid local part").that(rootNode.getLocalPart()).isEqualTo("ROOT");
   }
 
   @Test
-  public void testIterate() {
+  void iterate() {
     try (AxisIterator following = rootNode.iterateAxis(AxisInfo.FOLLOWING)) {
       assertWithMessage("Result iterator does not match expected")
           .that(following)
@@ -158,7 +158,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testRootWithNullDetailAst() {
+  void rootWithNullDetailAst() {
     final RootNode emptyRootNode = new RootNode(null);
     assertWithMessage("Empty node should not have children")
         .that(emptyRootNode.hasChildNodes())
@@ -177,7 +177,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetStringValue() {
+  void getStringValue() {
     try {
       rootNode.getStringValue();
       assertWithMessage("Exception is excepted").fail();
@@ -189,7 +189,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetAttributeValue() {
+  void getAttributeValue() {
     try {
       rootNode.getAttributeValue("", "");
       assertWithMessage("Exception is excepted").fail();
@@ -201,7 +201,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetDeclaredNamespaces() {
+  void getDeclaredNamespaces() {
     try {
       rootNode.getDeclaredNamespaces(null);
       assertWithMessage("Exception is excepted").fail();
@@ -213,7 +213,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testIsId() {
+  void isId() {
     try {
       rootNode.isId();
       assertWithMessage("Exception is excepted").fail();
@@ -225,7 +225,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testIsIdref() {
+  void isIdref() {
     try {
       rootNode.isIdref();
       assertWithMessage("Exception is excepted").fail();
@@ -237,7 +237,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testIsNilled() {
+  void isNilled() {
     try {
       rootNode.isNilled();
       assertWithMessage("Exception is excepted").fail();
@@ -249,7 +249,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testIsStreamed() {
+  void isStreamed() {
     try {
       rootNode.isStreamed();
       assertWithMessage("Exception is excepted").fail();
@@ -261,7 +261,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetConfiguration() {
+  void getConfiguration() {
     try {
       rootNode.getConfiguration();
       assertWithMessage("Exception is excepted").fail();
@@ -273,7 +273,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testSetSystemId() {
+  void setSystemId() {
     try {
       rootNode.setSystemId("1");
       assertWithMessage("Exception is excepted").fail();
@@ -285,7 +285,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetSystemId() {
+  void getSystemId() {
     try {
       rootNode.getSystemId();
       assertWithMessage("Exception is excepted").fail();
@@ -297,7 +297,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetPublicId() {
+  void getPublicId() {
     try {
       rootNode.getPublicId();
       assertWithMessage("Exception is excepted").fail();
@@ -309,7 +309,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testBaseUri() {
+  void baseUri() {
     try {
       rootNode.getBaseURI();
       assertWithMessage("Exception is excepted").fail();
@@ -321,7 +321,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testSaveLocation() {
+  void saveLocation() {
     try {
       rootNode.saveLocation();
       assertWithMessage("Exception is excepted").fail();
@@ -333,7 +333,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetStringValueCs() {
+  void getStringValueCs() {
     try {
       rootNode.getUnicodeStringValue();
       assertWithMessage("Exception is excepted").fail();
@@ -345,7 +345,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testFingerprint() {
+  void fingerprint() {
     try {
       rootNode.getFingerprint();
       assertWithMessage("Exception is excepted").fail();
@@ -357,7 +357,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetDisplayName() {
+  void getDisplayName() {
     try {
       rootNode.getDisplayName();
       assertWithMessage("Exception is excepted").fail();
@@ -369,7 +369,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetPrefix() {
+  void getPrefix() {
     try {
       rootNode.getPrefix();
       assertWithMessage("Exception is excepted").fail();
@@ -381,7 +381,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetSchemaType() {
+  void getSchemaType() {
     try {
       rootNode.getSchemaType();
       assertWithMessage("Exception is excepted").fail();
@@ -393,7 +393,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testAtomize() {
+  void atomize() {
     try {
       rootNode.atomize();
       assertWithMessage("Exception is excepted").fail();
@@ -405,7 +405,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGenerateId() {
+  void generateId() {
     try {
       rootNode.generateId(null);
       assertWithMessage("Exception is excepted").fail();
@@ -417,7 +417,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testCopy() {
+  void copy() {
     try {
       rootNode.copy(null, -1, null);
       assertWithMessage("Exception is excepted").fail();
@@ -429,7 +429,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testGetAllNamespaces() {
+  void getAllNamespaces() {
     try {
       rootNode.getAllNamespaces();
       assertWithMessage("Exception is excepted").fail();
@@ -441,7 +441,7 @@ public class RootNodeTest extends AbstractPathTestSupport {
   }
 
   @Test
-  public void testSameNodeInfo() {
+  void sameNodeInfo() {
     assertWithMessage("Should return true, because object is being compared to itself")
         .that(rootNode.isSameNodeInfo(rootNode))
         .isTrue();
--- a/src/test/java/com/puppycrawl/tools/checkstyle/xpath/XpathMapperTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/xpath/XpathMapperTest.java
@@ -31,7 +31,7 @@ import java.util.List;
 import net.sf.saxon.om.NodeInfo;
 import org.junit.jupiter.api.Test;
 
-public class XpathMapperTest extends AbstractModuleTestSupport {
+final class XpathMapperTest extends AbstractModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -39,7 +39,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNodeOrdering() throws Exception {
+  void nodeOrdering() throws Exception {
     final String xpath = "//METHOD_DEF/SLIST/*";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final List<NodeInfo> nodes = getXpathItems(xpath, rootNode);
@@ -60,7 +60,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFullPath() throws Exception {
+  void fullPath() throws Exception {
     final String xpath =
         "/COMPILATION_UNIT/CLASS_DEF/OBJBLOCK" + "/METHOD_DEF[1]/SLIST/VARIABLE_DEF[2]";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
@@ -79,7 +79,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testParent() throws Exception {
+  void parent() throws Exception {
     final String xpath = "(//VARIABLE_DEF)[1]/..";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -94,7 +94,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testCurlyBrackets() throws Exception {
+  void curlyBrackets() throws Exception {
     final String xpath = "(//RCURLY)[2]";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -110,7 +110,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testOr() throws Exception {
+  void or() throws Exception {
     final String xpath = "//CLASS_DEF | //METHOD_DEF";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -129,7 +129,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testComplexQueryOne() throws Exception {
+  void complexQueryOne() throws Exception {
     final String xpath = "//CLASS_DEF | //CLASS_DEF/OBJBLOCK";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -142,7 +142,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testComplexQueryTwo() throws Exception {
+  void complexQueryTwo() throws Exception {
     final String xpath = "//PACKAGE_DEF | //PACKAGE_DEF/ANNOTATIONS";
     final RootNode rootNode = getRootNode("InputXpathMapperAnnotation.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -156,7 +156,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testComplexQueryThree() throws Exception {
+  void complexQueryThree() throws Exception {
     final String xpath =
         "//CLASS_DEF | //CLASS_DEF//METHOD_DEF |" + " /COMPILATION_UNIT/CLASS_DEF/OBJBLOCK";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
@@ -176,7 +176,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAttributeOr() throws Exception {
+  void attributeOr() throws Exception {
     final String xpath =
         "//METHOD_DEF[./IDENT[@text='getSomeMethod'] " + "or ./IDENT[@text='nonExistentMethod']]";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
@@ -194,7 +194,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testAttributeAnd() throws Exception {
+  void attributeAnd() throws Exception {
     final String xpath =
         "//METHOD_DEF[./IDENT[@text='callSomeMethod'] and "
             + "../..[./IDENT[@text='InputXpathMapperAst']]]";
@@ -212,7 +212,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryAllElementsWithAttribute() throws Exception {
+  void queryAllElementsWithAttribute() throws Exception {
     final String xpath = "//*[./IDENT[@text]]";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final List<NodeInfo> nodes = getXpathItems(xpath, rootNode);
@@ -220,7 +220,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryElementByIndex() throws Exception {
+  void queryElementByIndex() throws Exception {
     final String xpath = "(//VARIABLE_DEF)[1]";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -237,7 +237,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryAllVariableDefinitionsWithAttribute() throws Exception {
+  void queryAllVariableDefinitionsWithAttribute() throws Exception {
     final String xpath = "//VARIABLE_DEF[./IDENT[@*]]";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final List<NodeInfo> nodes = getXpathItems(xpath, rootNode);
@@ -245,7 +245,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryAllVariableDefWrongAttribute() throws Exception {
+  void queryAllVariableDefWrongAttribute() throws Exception {
     final String xpath = "//VARIABLE_DEF[@qwe]";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final List<NodeInfo> nodes = getXpathItems(xpath, rootNode);
@@ -253,7 +253,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryAllMethodDefinitionsInContext() throws Exception {
+  void queryAllMethodDefinitionsInContext() throws Exception {
     final String objectXpath = "//CLASS_DEF[./IDENT[@text='InputXpathMapperAst']]//OBJBLOCK";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final List<NodeInfo> objectNodes = getXpathItems(objectXpath, rootNode);
@@ -279,7 +279,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryAllClassDefinitions() throws Exception {
+  void queryAllClassDefinitions() throws Exception {
     final String xpath = "/COMPILATION_UNIT/CLASS_DEF";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final List<NodeInfo> nodes = getXpathItems(xpath, rootNode);
@@ -296,7 +296,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryByMethodName() throws Exception {
+  void queryByMethodName() throws Exception {
     final String xpath = "//METHOD_DEF[./IDENT[@text='getSomeMethod']]";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -311,7 +311,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryMethodDefinitionsByClassName() throws Exception {
+  void queryMethodDefinitionsByClassName() throws Exception {
     final String xpath =
         "//CLASS_DEF[./IDENT[@text='InputXpathMapperAst']]" + "//OBJBLOCK//METHOD_DEF";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
@@ -332,7 +332,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryByClassNameAndMethodName() throws Exception {
+  void queryByClassNameAndMethodName() throws Exception {
     final String xpath =
         "//CLASS_DEF[./IDENT[@text='InputXpathMapperAst']]//OBJBLOCK"
             + "//METHOD_DEF[./IDENT[@text='getSomeMethod']]";
@@ -349,7 +349,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryClassDefinitionByClassName() throws Exception {
+  void queryClassDefinitionByClassName() throws Exception {
     final String xpath = "//CLASS_DEF[./IDENT[@text='InputXpathMapperAst']]";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final List<NodeInfo> nodes = getXpathItems(xpath, rootNode);
@@ -364,7 +364,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryWrongClassName() throws Exception {
+  void queryWrongClassName() throws Exception {
     final String xpath = "/CLASS_DEF[@text='WrongName']";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final List<NodeInfo> nodes = getXpathItems(xpath, rootNode);
@@ -372,7 +372,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryWrongXpath() throws Exception {
+  void queryWrongXpath() throws Exception {
     final String xpath = "/WRONG_XPATH";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final List<NodeInfo> nodes = getXpathItems(xpath, rootNode);
@@ -380,7 +380,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryAncestor() throws Exception {
+  void queryAncestor() throws Exception {
     final String xpath = "//VARIABLE_DEF[./IDENT[@text='another']]/ancestor::METHOD_DEF";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -394,7 +394,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryAncestorOrSelf() throws Exception {
+  void queryAncestorOrSelf() throws Exception {
     final String xpath =
         "//VARIABLE_DEF[./IDENT[@text='another']]" + "/ancestor-or-self::VARIABLE_DEF";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
@@ -413,7 +413,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryDescendant() throws Exception {
+  void queryDescendant() throws Exception {
     final String xpath = "//METHOD_DEF/descendant::EXPR";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final List<NodeInfo> nodes = getXpathItems(xpath, rootNode);
@@ -421,7 +421,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryDescendantOrSelf() throws Exception {
+  void queryDescendantOrSelf() throws Exception {
     final String xpath = "//METHOD_DEF/descendant-or-self::METHOD_DEF";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -441,7 +441,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryNoChild() throws Exception {
+  void queryNoChild() throws Exception {
     final String xpath = "//RCURLY/METHOD_DEF";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final List<NodeInfo> nodes = getXpathItems(xpath, rootNode);
@@ -449,7 +449,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryNoDescendant() throws Exception {
+  void queryNoDescendant() throws Exception {
     final String xpath = "//RCURLY/descendant::METHOD_DEF";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final List<NodeInfo> nodes = getXpathItems(xpath, rootNode);
@@ -457,7 +457,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryRootNotImplementedAxis() throws Exception {
+  void queryRootNotImplementedAxis() throws Exception {
     final String xpath = "//namespace::*";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     try {
@@ -471,7 +471,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryElementNotImplementedAxis() throws Exception {
+  void queryElementNotImplementedAxis() throws Exception {
     final String xpath = "/COMPILATION_UNIT/CLASS_DEF//namespace::*";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     try {
@@ -485,7 +485,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQuerySelf() throws Exception {
+  void querySelf() throws Exception {
     final String objectXpath = "//CLASS_DEF[./IDENT[@text='InputXpathMapperAst']]//OBJBLOCK";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final List<NodeInfo> objectNodes = getXpathItems(objectXpath, rootNode);
@@ -502,7 +502,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryNonExistentAttribute() throws Exception {
+  void queryNonExistentAttribute() throws Exception {
     final String xpath = "//CLASS_DEF[./IDENT[@text='InputXpathMapperAst']]";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final List<NodeInfo> nodes = getXpathItems(xpath, rootNode);
@@ -513,7 +513,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryRootSelf() throws Exception {
+  void queryRootSelf() throws Exception {
     final String xpath = "self::node()";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final List<NodeInfo> nodes = getXpathItems(xpath, rootNode);
@@ -521,7 +521,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryAnnotation() throws Exception {
+  void queryAnnotation() throws Exception {
     final String xpath = "//ANNOTATION[./IDENT[@text='Deprecated']]";
     final RootNode rootNode = getRootNode("InputXpathMapperAnnotation.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -535,7 +535,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryNonExistentAnnotation() throws Exception {
+  void queryNonExistentAnnotation() throws Exception {
     final String xpath = "//ANNOTATION[@text='SpringBootApplication']";
     final RootNode rootNode = getRootNode("InputXpathMapperAnnotation.java");
     final List<NodeInfo> nodes = getXpathItems(xpath, rootNode);
@@ -543,7 +543,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryEnumDef() throws Exception {
+  void queryEnumDef() throws Exception {
     final String xpath = "/COMPILATION_UNIT/ENUM_DEF";
     final RootNode enumRootNode = getRootNode("InputXpathMapperEnum.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, enumRootNode));
@@ -555,7 +555,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryEnumElementsNumber() throws Exception {
+  void queryEnumElementsNumber() throws Exception {
     final String xpath = "/COMPILATION_UNIT/ENUM_DEF/OBJBLOCK/ENUM_CONSTANT_DEF";
     final RootNode enumRootNode = getRootNode("InputXpathMapperEnum.java");
     final List<NodeInfo> nodes = getXpathItems(xpath, enumRootNode);
@@ -563,7 +563,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryEnumElementByName() throws Exception {
+  void queryEnumElementByName() throws Exception {
     final String xpath = "//*[./IDENT[@text='TWO']]";
     final RootNode enumRootNode = getRootNode("InputXpathMapperEnum.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, enumRootNode));
@@ -579,7 +579,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryInterfaceDef() throws Exception {
+  void queryInterfaceDef() throws Exception {
     final String xpath = "//INTERFACE_DEF";
     final RootNode interfaceRootNode = getRootNode("InputXpathMapperInterface.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, interfaceRootNode));
@@ -591,7 +591,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryInterfaceMethodDefNumber() throws Exception {
+  void queryInterfaceMethodDefNumber() throws Exception {
     final String xpath = "//INTERFACE_DEF/OBJBLOCK/METHOD_DEF";
     final RootNode interfaceRootNode = getRootNode("InputXpathMapperInterface.java");
     final List<NodeInfo> nodes = getXpathItems(xpath, interfaceRootNode);
@@ -599,7 +599,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryInterfaceParameterDef() throws Exception {
+  void queryInterfaceParameterDef() throws Exception {
     final String xpath = "//PARAMETER_DEF[./IDENT[@text='someVariable']]/../..";
     final RootNode interfaceRootNode = getRootNode("InputXpathMapperInterface.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, interfaceRootNode));
@@ -614,7 +614,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIdent() throws Exception {
+  void ident() throws Exception {
     final String xpath = "//CLASS_DEF/IDENT[@text='InputXpathMapperAst']";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final List<NodeInfo> nodes = getXpathItems(xpath, rootNode);
@@ -629,7 +629,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIdentByText() throws Exception {
+  void identByText() throws Exception {
     final String xpath = "//IDENT[@text='puppycrawl']";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -648,7 +648,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testNumVariableByItsValue() throws Exception {
+  void numVariableByItsValue() throws Exception {
     final String xpath = "//VARIABLE_DEF[.//NUM_INT[@text=123]]";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -664,7 +664,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testStringVariableByItsValue() throws Exception {
+  void stringVariableByItsValue() throws Exception {
     final String xpath = "//VARIABLE_DEF[./ASSIGN/EXPR" + "/STRING_LITERAL[@text='HelloWorld']]";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -682,7 +682,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSameNodesByNameAndByText() throws Exception {
+  void sameNodesByNameAndByText() throws Exception {
     final String xpath1 = "//VARIABLE_DEF[./IDENT[@text='another']]/ASSIGN/EXPR/STRING_LITERAL";
     final String xpath2 = "//VARIABLE_DEF/ASSIGN/EXPR/STRING_LITERAL[@text='HelloWorld']";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
@@ -692,7 +692,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMethodDefByAnnotationValue() throws Exception {
+  void methodDefByAnnotationValue() throws Exception {
     final String xpath =
         "//METHOD_DEF[.//ANNOTATION[./IDENT[@text='SuppressWarnings']"
             + " and .//*[@text='good']]]";
@@ -709,7 +709,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFirstImport() throws Exception {
+  void firstImport() throws Exception {
     final String xpath = "/COMPILATION_UNIT/IMPORT[1]";
     final RootNode rootNode = getRootNode("InputXpathMapperPositions.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -721,7 +721,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSecondImport() throws Exception {
+  void secondImport() throws Exception {
     final String xpath = "/COMPILATION_UNIT/IMPORT[2]";
     final RootNode rootNode = getRootNode("InputXpathMapperPositions.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -734,7 +734,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testThirdImport() throws Exception {
+  void thirdImport() throws Exception {
     final String xpath = "/COMPILATION_UNIT/IMPORT[3]";
     final RootNode rootNode = getRootNode("InputXpathMapperPositions.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -748,7 +748,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLastImport() throws Exception {
+  void lastImport() throws Exception {
     final String xpath = "/COMPILATION_UNIT/IMPORT[9]";
     final RootNode rootNode = getRootNode("InputXpathMapperPositions.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -768,7 +768,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFirstCaseGroup() throws Exception {
+  void firstCaseGroup() throws Exception {
     final String xpath =
         "//CLASS_DEF[./IDENT[@text='InputXpathMapperPositions']]"
             + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='switchMethod']]"
@@ -788,7 +788,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSecondCaseGroup() throws Exception {
+  void secondCaseGroup() throws Exception {
     final String xpath =
         "//CLASS_DEF[./IDENT[@text='InputXpathMapperPositions']]"
             + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='switchMethod']]"
@@ -809,7 +809,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testThirdCaseGroup() throws Exception {
+  void thirdCaseGroup() throws Exception {
     final String xpath =
         "//CLASS_DEF[./IDENT[@text='InputXpathMapperPositions']]"
             + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='switchMethod']]"
@@ -831,7 +831,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFourthCaseGroup() throws Exception {
+  void fourthCaseGroup() throws Exception {
     final String xpath =
         "//CLASS_DEF[./IDENT[@text='InputXpathMapperPositions']]"
             + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='switchMethod']]"
@@ -854,7 +854,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryElementFollowingSibling() throws Exception {
+  void queryElementFollowingSibling() throws Exception {
     final String xpath = "//METHOD_DEF/following-sibling::*";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -873,7 +873,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryElementNoFollowingSibling() throws Exception {
+  void queryElementNoFollowingSibling() throws Exception {
     final String xpath = "//CLASS_DEF/following-sibling::*";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -881,7 +881,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryElementFollowingSiblingRcurly() throws Exception {
+  void queryElementFollowingSiblingRcurly() throws Exception {
     final String xpath = "//METHOD_DEF/following-sibling::RCURLY";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -897,7 +897,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryElementFollowing() throws Exception {
+  void queryElementFollowing() throws Exception {
     final String xpath = "//IDENT[@text='variable']/following::*";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final List<NodeInfo> actual = getXpathItems(xpath, rootNode);
@@ -907,7 +907,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryElementFollowingTwo() throws Exception {
+  void queryElementFollowingTwo() throws Exception {
     final String xpath = "//LITERAL_RETURN[.//STRING_LITERAL[@text='HelloWorld']]/following::*";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -928,7 +928,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryElementFollowingMethodDef() throws Exception {
+  void queryElementFollowingMethodDef() throws Exception {
     final String xpath = "//PACKAGE_DEF/following::METHOD_DEF";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -948,7 +948,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryElementNoFollowing() throws Exception {
+  void queryElementNoFollowing() throws Exception {
     final String xpath = "//CLASS_DEF/following::*";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -956,7 +956,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryElementPrecedingSibling() throws Exception {
+  void queryElementPrecedingSibling() throws Exception {
     final String xpath = "//VARIABLE_DEF[./IDENT[@text='array']]/preceding-sibling::*";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -977,7 +977,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryElementPrecedingSiblingVariableDef() throws Exception {
+  void queryElementPrecedingSiblingVariableDef() throws Exception {
     final String xpath =
         "//VARIABLE_DEF[./IDENT[@text='array']]/preceding-sibling::" + "VARIABLE_DEF";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
@@ -996,7 +996,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryElementPrecedingSiblingArray() throws Exception {
+  void queryElementPrecedingSiblingArray() throws Exception {
     final String xpath = "//VARIABLE_DEF[./IDENT[@text='array']]/preceding-sibling::*[1]";
     final RootNode rootNode = getRootNode("InputXpathMapperAst.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -1014,7 +1014,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryElementPrecedingOne() throws Exception {
+  void queryElementPrecedingOne() throws Exception {
     final String xpath = "//LITERAL_CLASS/preceding::*";
     final RootNode rootNode = getRootNode("InputXpathMapperSingleTopClass.java");
     final DetailAST[] actual =
@@ -1023,7 +1023,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryElementPrecedingTwo() throws Exception {
+  void queryElementPrecedingTwo() throws Exception {
     final String xpath = "//PACKAGE_DEF/DOT/preceding::*";
     final RootNode rootNode = getRootNode("InputXpathMapperSingleTopClass.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -1038,7 +1038,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQueryElementPrecedingLiteralPublic() throws Exception {
+  void queryElementPrecedingLiteralPublic() throws Exception {
     final String xpath = "//LITERAL_CLASS/preceding::LITERAL_PUBLIC";
     final RootNode rootNode = getRootNode("InputXpathMapperSingleTopClass.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -1052,7 +1052,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTextBlockByItsValue() throws Exception {
+  void textBlockByItsValue() throws Exception {
     final String xpath =
         "//TEXT_BLOCK_LITERAL_BEGIN[./TEXT_BLOCK_CONTENT"
             + "[@text='\\n        &1line\\n        >2line\\n        <3line\\n        ']]";
@@ -1071,7 +1071,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testQuerySingleLineCommentByCommentContent() throws Exception {
+  void querySingleLineCommentByCommentContent() throws Exception {
     final String xpath = "//SINGLE_LINE_COMMENT[./COMMENT_CONTENT[@text=' some comment\\n']]";
     final RootNode rootNode = getRootNodeWithComments("InputXpathMapperSingleLineComment.java");
     final DetailAST[] actual = convertToArray(getXpathItems(xpath, rootNode));
@@ -1085,7 +1085,7 @@ public class XpathMapperTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testManyNestedNodes() throws Exception {
+  void manyNestedNodes() throws Exception {
     final String xpath = "//STRING_LITERAL";
     final RootNode rootNode = getRootNode("InputXpathMapperStringConcat.java");
     final List<NodeInfo> actual = getXpathItems(xpath, rootNode);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/xpath/XpathQueryGeneratorTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/xpath/XpathQueryGeneratorTest.java
@@ -21,6 +21,7 @@ package com.puppycrawl.tools.checkstyle.xpath;
 
 import static com.google.common.truth.Truth.assertWithMessage;
 
+import com.google.common.collect.ImmutableList;
 import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.JavaParser;
 import com.puppycrawl.tools.checkstyle.TreeWalkerAuditEvent;
@@ -32,12 +33,11 @@ import com.puppycrawl.tools.checkstyle.api.Violation;
 import java.io.File;
 import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
+final class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
 
   private static final int DEFAULT_TAB_WIDTH = 4;
 
@@ -51,14 +51,14 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @BeforeEach
-  public void init() throws Exception {
+  void init() throws Exception {
     final File file = new File(getPath("InputXpathQueryGenerator.java"));
     fileText = new FileText(file, StandardCharsets.UTF_8.name());
     rootAst = JavaParser.parseFile(file, JavaParser.Options.WITH_COMMENTS);
   }
 
   @Test
-  public void testClassDef() {
+  void classDef() {
     final int lineNumber = 12;
     final int columnNumber = 1;
     final XpathQueryGenerator queryGenerator =
@@ -76,7 +76,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testMethodDef() {
+  void methodDef() {
     final int lineNumber = 45;
     final int columnNumber = 5;
     final XpathQueryGenerator queryGenerator =
@@ -96,7 +96,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testVariableDef() {
+  void variableDef() {
     final int lineNumber = 53;
     final int columnNumber = 13;
     final XpathQueryGenerator queryGenerator =
@@ -126,14 +126,14 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLcurly() {
+  void lcurly() {
     final int lineNumber = 37;
     final int columnNumber = 20;
     final XpathQueryGenerator queryGenerator =
         new XpathQueryGenerator(rootAst, lineNumber, columnNumber, fileText, DEFAULT_TAB_WIDTH);
     final List<String> actual = queryGenerator.generate();
     final List<String> expected =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT[@text='InputXpathQueryGenerator']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='Label']]/SLIST/LITERAL_SWITCH/LCURLY");
     assertWithMessage("Generated queries do not match expected ones")
@@ -142,14 +142,14 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testRcurly() {
+  void rcurly() {
     final int lineNumber = 25;
     final int columnNumber = 5;
     final XpathQueryGenerator queryGenerator =
         new XpathQueryGenerator(rootAst, lineNumber, columnNumber, fileText, DEFAULT_TAB_WIDTH);
     final List<String> actual = queryGenerator.generate();
     final List<String> expected =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT[@text='InputXpathQueryGenerator']]/OBJBLOCK"
                 + "/INSTANCE_INIT/SLIST/RCURLY");
     assertWithMessage("Generated queries do not match expected ones")
@@ -158,7 +158,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testExpr() {
+  void expr() {
     final int lineNumber = 17;
     final int columnNumber = 50;
     final XpathQueryGenerator queryGenerator =
@@ -176,14 +176,14 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLparen() {
+  void lparen() {
     final int lineNumber = 45;
     final int columnNumber = 31;
     final XpathQueryGenerator queryGenerator =
         new XpathQueryGenerator(rootAst, lineNumber, columnNumber, fileText, DEFAULT_TAB_WIDTH);
     final List<String> actual = queryGenerator.generate();
     final List<String> expected =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT[@text='InputXpathQueryGenerator']]/OBJBLOCK"
                 + "/METHOD_DEF[./IDENT[@text='callSomeMethod']]/LPAREN");
     assertWithMessage("Generated queries do not match expected ones")
@@ -192,7 +192,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEmpty() {
+  void empty() {
     final int lineNumber = 300;
     final int columnNumber = 300;
     final XpathQueryGenerator queryGenerator =
@@ -202,7 +202,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testPackage() {
+  void testPackage() {
     final int lineNumber = 2;
     final int columnNumber = 1;
     final XpathQueryGenerator queryGenerator =
@@ -216,21 +216,21 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testImport() {
+  void testImport() {
     final int lineNumber = 5;
     final int columnNumber = 1;
     final XpathQueryGenerator queryGenerator =
         new XpathQueryGenerator(rootAst, lineNumber, columnNumber, fileText, DEFAULT_TAB_WIDTH);
     final List<String> actual = queryGenerator.generate();
     final List<String> expected =
-        Collections.singletonList("/COMPILATION_UNIT/IMPORT[./DOT/IDENT[@text='File']]");
+        ImmutableList.of("/COMPILATION_UNIT/IMPORT[./DOT/IDENT[@text='File']]");
     assertWithMessage("Generated queries do not match expected ones")
         .that(actual)
         .isEqualTo(expected);
   }
 
   @Test
-  public void testMethodParams() {
+  void methodParams() {
     final int lineNumber = 72;
     final int columnNumber = 30;
     final XpathQueryGenerator queryGenerator =
@@ -262,14 +262,14 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSwitch() {
+  void testSwitch() {
     final int lineNumber = 37;
     final int columnNumber = 9;
     final XpathQueryGenerator queryGenerator =
         new XpathQueryGenerator(rootAst, lineNumber, columnNumber, fileText, DEFAULT_TAB_WIDTH);
     final List<String> actual = queryGenerator.generate();
     final List<String> expected =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT[@text='InputXpathQueryGenerator']]"
                 + "/OBJBLOCK/METHOD_DEF[./IDENT[@text='Label']]/SLIST/LITERAL_SWITCH");
     assertWithMessage("Generated queries do not match expected ones")
@@ -278,7 +278,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testSwitchCase() {
+  void switchCase() {
     final int lineNumber = 38;
     final int columnNumber = 13;
     final XpathQueryGenerator queryGenerator =
@@ -298,7 +298,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testVariableStringLiteral() {
+  void variableStringLiteral() {
     final int lineNumber = 47;
     final int columnNumber = 26;
     final XpathQueryGenerator queryGenerator =
@@ -320,14 +320,14 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testComma() {
+  void comma() {
     final int lineNumber = 66;
     final int columnNumber = 36;
     final XpathQueryGenerator queryGenerator =
         new XpathQueryGenerator(rootAst, lineNumber, columnNumber, fileText, DEFAULT_TAB_WIDTH);
     final List<String> actual = queryGenerator.generate();
     final List<String> expected =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='InputXpathQueryGenerator']]/OBJBLOCK/METHOD_DEF["
                 + "./IDENT[@text='foo']]/SLIST/LITERAL_FOR/FOR_ITERATOR/ELIST/COMMA");
@@ -337,7 +337,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testLiteralVoid() {
+  void literalVoid() {
     final int lineNumber = 65;
     final int columnNumber = 12;
     final XpathQueryGenerator queryGenerator =
@@ -355,42 +355,42 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testFirstImport() {
+  void firstImport() {
     final int lineNumber = 4;
     final int columnNumber = 1;
     final XpathQueryGenerator queryGenerator =
         new XpathQueryGenerator(rootAst, lineNumber, columnNumber, fileText, DEFAULT_TAB_WIDTH);
     final List<String> actual = queryGenerator.generate();
     final List<String> expected =
-        Collections.singletonList("/COMPILATION_UNIT/IMPORT[./DOT/IDENT[@text='JToolBar']]");
+        ImmutableList.of("/COMPILATION_UNIT/IMPORT[./DOT/IDENT[@text='JToolBar']]");
     assertWithMessage("Generated queries do not match expected ones")
         .that(actual)
         .isEqualTo(expected);
   }
 
   @Test
-  public void testLastImport() {
+  void lastImport() {
     final int lineNumber = 8;
     final int columnNumber = 1;
     final XpathQueryGenerator queryGenerator =
         new XpathQueryGenerator(rootAst, lineNumber, columnNumber, fileText, DEFAULT_TAB_WIDTH);
     final List<String> actual = queryGenerator.generate();
     final List<String> expected =
-        Collections.singletonList("/COMPILATION_UNIT/IMPORT[./DOT/IDENT[@text='Iterator']]");
+        ImmutableList.of("/COMPILATION_UNIT/IMPORT[./DOT/IDENT[@text='Iterator']]");
     assertWithMessage("Generated queries do not match expected ones")
         .that(actual)
         .isEqualTo(expected);
   }
 
   @Test
-  public void testImportByText() {
+  void importByText() {
     final int lineNumber = 4;
     final int columnNumber = 8;
     final XpathQueryGenerator queryGenerator =
         new XpathQueryGenerator(rootAst, lineNumber, columnNumber, fileText, DEFAULT_TAB_WIDTH);
     final List<String> actual = queryGenerator.generate();
     final List<String> expected =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/IMPORT/DOT[./IDENT[@text='JToolBar']]/DOT/IDENT[@text='javax']");
     assertWithMessage("Generated queries do not match expected ones")
         .that(actual)
@@ -398,22 +398,21 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testIdent() {
+  void ident() {
     final int lineNumber = 12;
     final int columnNumber = 14;
     final XpathQueryGenerator queryGenerator =
         new XpathQueryGenerator(rootAst, lineNumber, columnNumber, fileText, DEFAULT_TAB_WIDTH);
     final List<String> actual = queryGenerator.generate();
     final List<String> expected =
-        Collections.singletonList(
-            "/COMPILATION_UNIT/CLASS_DEF/IDENT[@text='InputXpathQueryGenerator']");
+        ImmutableList.of("/COMPILATION_UNIT/CLASS_DEF/IDENT[@text='InputXpathQueryGenerator']");
     assertWithMessage("Generated queries do not match expected ones")
         .that(actual)
         .isEqualTo(expected);
   }
 
   @Test
-  public void testTabWidthBeforeMethodDef() throws Exception {
+  void tabWidthBeforeMethodDef() throws Exception {
     final File testFile = new File(getPath("InputXpathQueryGeneratorTabWidth.java"));
     final FileText testFileText = new FileText(testFile, StandardCharsets.UTF_8.name());
     final DetailAST detailAst = JavaParser.parseFile(testFile, JavaParser.Options.WITHOUT_COMMENTS);
@@ -440,7 +439,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTabWidthAfterVoidLiteral() throws Exception {
+  void tabWidthAfterVoidLiteral() throws Exception {
     final File testFile = new File(getPath("InputXpathQueryGeneratorTabWidth.java"));
     final FileText testFileText = new FileText(testFile, StandardCharsets.UTF_8.name());
     final DetailAST detailAst = JavaParser.parseFile(testFile, JavaParser.Options.WITHOUT_COMMENTS);
@@ -464,7 +463,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTabWidthBeforeSlist() throws Exception {
+  void tabWidthBeforeSlist() throws Exception {
     final File testFile = new File(getPath("InputXpathQueryGeneratorTabWidth.java"));
     final FileText testFileText = new FileText(testFile, StandardCharsets.UTF_8.name());
     final DetailAST detailAst = JavaParser.parseFile(testFile, JavaParser.Options.WITHOUT_COMMENTS);
@@ -475,7 +474,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
         new XpathQueryGenerator(detailAst, lineNumber, columnNumber, testFileText, tabWidth);
     final List<String> actual = queryGenerator.generate();
     final List<String> expected =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='InputXpathQueryGeneratorTabWidth']]/OBJBLOCK"
                 + "/METHOD_DEF[./IDENT[@text='tabAfterMe']]/SLIST");
@@ -485,7 +484,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTabWidthEndOfLine() throws Exception {
+  void tabWidthEndOfLine() throws Exception {
     final File testFile = new File(getPath("InputXpathQueryGeneratorTabWidth.java"));
     final FileText testFileText = new FileText(testFile, StandardCharsets.UTF_8.name());
     final DetailAST detailAst = JavaParser.parseFile(testFile, JavaParser.Options.WITHOUT_COMMENTS);
@@ -496,7 +495,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
         new XpathQueryGenerator(detailAst, lineNumber, columnNumber, testFileText, tabWidth);
     final List<String> actual = queryGenerator.generate();
     final List<String> expected =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT[@text='InputXpathQueryGeneratorTabWidth']]"
                 + "/OBJBLOCK/VARIABLE_DEF[./IDENT[@text='endLineTab']]/SEMI");
     assertWithMessage("Generated queries do not match expected ones")
@@ -505,7 +504,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testClassDefWithTokenType() {
+  void classDefWithTokenType() {
     final int lineNumber = 12;
     final int columnNumber = 1;
     final XpathQueryGenerator queryGenerator =
@@ -513,15 +512,14 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
             rootAst, lineNumber, columnNumber, TokenTypes.CLASS_DEF, fileText, DEFAULT_TAB_WIDTH);
     final List<String> actual = queryGenerator.generate();
     final List<String> expected =
-        Collections.singletonList(
-            "/COMPILATION_UNIT/CLASS_DEF[./IDENT[@text='InputXpathQueryGenerator']]");
+        ImmutableList.of("/COMPILATION_UNIT/CLASS_DEF[./IDENT[@text='InputXpathQueryGenerator']]");
     assertWithMessage("Generated queries do not match expected ones")
         .that(actual)
         .isEqualTo(expected);
   }
 
   @Test
-  public void testConstructorWithTreeWalkerAuditEvent() {
+  void constructorWithTreeWalkerAuditEvent() {
     final Violation violation =
         new Violation(12, 1, "messages.properties", null, null, null, null, null, null);
     final TreeWalkerAuditEvent event =
@@ -541,7 +539,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testEscapeCharacters() throws Exception {
+  void escapeCharacters() throws Exception {
     final File testFile = new File(getPath("InputXpathQueryGeneratorEscapeCharacters.java"));
     final FileText testFileText = new FileText(testFile, StandardCharsets.UTF_8.name());
     final DetailAST detailAst = JavaParser.parseFile(testFile, JavaParser.Options.WITHOUT_COMMENTS);
@@ -589,7 +587,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTextBlocks() throws Exception {
+  void textBlocks() throws Exception {
     final File testFile = new File(getNonCompilablePath("InputXpathQueryGeneratorTextBlock.java"));
     final FileText testFileText = new FileText(testFile, StandardCharsets.UTF_8.name());
     final DetailAST detailAst = JavaParser.parseFile(testFile, JavaParser.Options.WITHOUT_COMMENTS);
@@ -601,7 +599,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
         new XpathQueryGenerator(detailAst, lineNumber, columnNumber, testFileText, tabWidth);
     final List<String> actual = queryGenerator.generate();
     final List<String> expected =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='InputXpathQueryGeneratorTextBlock']]/OBJBLOCK/"
                 + "VARIABLE_DEF[./IDENT[@text='testOne']]/ASSIGN/EXPR/"
@@ -613,7 +611,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTextBlocksWithNewLine() throws Exception {
+  void textBlocksWithNewLine() throws Exception {
     final File testFile =
         new File(getNonCompilablePath("InputXpathQueryGeneratorTextBlockNewLine.java"));
     final FileText testFileText = new FileText(testFile, StandardCharsets.UTF_8.name());
@@ -626,7 +624,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
         new XpathQueryGenerator(detailAst, lineNumber, columnNumber, testFileText, tabWidth);
     final List<String> actual = queryGenerator.generate();
     final List<String> expected =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='InputXpathQueryGeneratorTextBlockNewLine']]/OBJBLOCK/"
                 + "VARIABLE_DEF[./IDENT[@text='testOne']]/ASSIGN/EXPR/"
@@ -638,7 +636,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testTextBlocksWithNewCrlf() throws Exception {
+  void textBlocksWithNewCrlf() throws Exception {
     final File testFile =
         new File(getNonCompilablePath("InputXpathQueryGeneratorTextBlockCrlf.java"));
     final FileText testFileText = new FileText(testFile, StandardCharsets.UTF_8.name());
@@ -651,7 +649,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
         new XpathQueryGenerator(detailAst, lineNumber, columnNumber, testFileText, tabWidth);
     final List<String> actual = queryGenerator.generate();
     final List<String> expected =
-        Collections.singletonList(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='InputXpathQueryGeneratorTextBlockCrlf']]/OBJBLOCK/"
                 + "VARIABLE_DEF[./IDENT[@text='testOne']]/ASSIGN/EXPR/"
@@ -664,7 +662,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testXpath() throws Exception {
+  void xpath() throws Exception {
     final File testFile = new File(getPath("InputXpathQueryGenerator2.java"));
     final FileText testFileText = new FileText(testFile, StandardCharsets.UTF_8.name());
     final DetailAST detailAst = JavaParser.parseFile(testFile, JavaParser.Options.WITHOUT_COMMENTS);
@@ -676,7 +674,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
         new XpathQueryGenerator(detailAst, lineNumberOne, columnNumberOne, testFileText, tabWidth);
     final List<String> actualTestOne = queryGeneratorOne.generate();
     final List<String> expectedTestOne =
-        List.of(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF"
                 + "[./IDENT[@text='InputXpathQueryGenerator2']]"
                 + "/OBJBLOCK/ENUM_DEF[./IDENT[@text='Foo3']]/OBJBLOCK/COMMA[2]");
@@ -686,7 +684,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testXpath2() throws Exception {
+  void xpath2() throws Exception {
     final File testFile = new File(getPath("InputXpathQueryGenerator3.java"));
     final FileText testFileText = new FileText(testFile, StandardCharsets.UTF_8.name());
     final DetailAST detailAst = JavaParser.parseFile(testFile, JavaParser.Options.WITHOUT_COMMENTS);
@@ -698,7 +696,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
         new XpathQueryGenerator(detailAst, lineNumber3, columnNumber3, testFileText, tabWidth);
     final List<String> actualTest3 = queryGenerator3.generate();
     final List<String> expectedTest3 =
-        List.of(
+        ImmutableList.of(
             "/COMPILATION_UNIT/CLASS_DEF[./IDENT[@text='InputXpathQueryGenerator3']]"
                 + "/OBJBLOCK/SEMI[1]");
     assertWithMessage("Generated queries do not match expected ones")
@@ -707,7 +705,7 @@ public class XpathQueryGeneratorTest extends AbstractModuleTestSupport {
   }
 
   @Test
-  public void testXpath3() throws Exception {
+  void xpath3() throws Exception {
     final File testFile = new File(getPath("InputXpathQueryGenerator4.java"));
     final FileText testFileText = new FileText(testFile, StandardCharsets.UTF_8.name());
     final DetailAST detailAst = JavaParser.parseFile(testFile, JavaParser.Options.WITHOUT_COMMENTS);
--- a/src/test/java/com/puppycrawl/tools/checkstyle/xpath/iterators/DescendantIteratorTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/xpath/iterators/DescendantIteratorTest.java
@@ -25,10 +25,10 @@ import static com.puppycrawl.tools.checkstyle.internal.utils.XpathIteratorUtil.f
 import net.sf.saxon.om.NodeInfo;
 import org.junit.jupiter.api.Test;
 
-public class DescendantIteratorTest {
+final class DescendantIteratorTest {
 
   @Test
-  public void testIncludeSelf() {
+  void includeSelf() {
     final NodeInfo startNode = findNode("CLASS_DEF");
 
     try (DescendantIterator iterator =
@@ -46,7 +46,7 @@ public class DescendantIteratorTest {
   }
 
   @Test
-  public void testWithoutSelf() {
+  void withoutSelf() {
     final NodeInfo startNode = findNode("CLASS_DEF");
 
     try (DescendantIterator iterator =
@@ -62,7 +62,7 @@ public class DescendantIteratorTest {
   }
 
   @Test
-  public void testWithNull() {
+  void withNull() {
     final NodeInfo startNode = findNode("CLASS_DEF");
 
     try (DescendantIterator iterator = new DescendantIterator(startNode, null)) {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/xpath/iterators/FollowingIteratorTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/xpath/iterators/FollowingIteratorTest.java
@@ -25,10 +25,10 @@ import static com.puppycrawl.tools.checkstyle.internal.utils.XpathIteratorUtil.f
 import net.sf.saxon.om.NodeInfo;
 import org.junit.jupiter.api.Test;
 
-public class FollowingIteratorTest {
+final class FollowingIteratorTest {
 
   @Test
-  public void testFollowingSibling() {
+  void followingSibling() {
     final NodeInfo startNode = findNode("ANNOTATIONS");
 
     try (FollowingIterator iterator = new FollowingIterator(startNode)) {
@@ -45,7 +45,7 @@ public class FollowingIteratorTest {
   }
 
   @Test
-  public void testNoSibling() {
+  void noSibling() {
     final NodeInfo startNode = findNode("CLASS_DEF");
 
     try (FollowingIterator iterator = new FollowingIterator(startNode)) {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/xpath/iterators/PrecedingIteratorTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/xpath/iterators/PrecedingIteratorTest.java
@@ -25,10 +25,10 @@ import static com.puppycrawl.tools.checkstyle.internal.utils.XpathIteratorUtil.f
 import net.sf.saxon.om.NodeInfo;
 import org.junit.jupiter.api.Test;
 
-public class PrecedingIteratorTest {
+final class PrecedingIteratorTest {
 
   @Test
-  public void testPrecedingNodes() {
+  void precedingNodes() {
     final NodeInfo startNode = findNode("SLIST");
 
     try (PrecedingIterator iterator = new PrecedingIterator(startNode)) {
@@ -47,7 +47,7 @@ public class PrecedingIteratorTest {
   }
 
   @Test
-  public void testNoParent() {
+  void noParent() {
     final NodeInfo startNode = findNode("ROOT");
 
     try (PrecedingIterator iterator = new PrecedingIterator(startNode)) {
@@ -56,7 +56,7 @@ public class PrecedingIteratorTest {
   }
 
   @Test
-  public void testReverseOrderOfDescendants() {
+  void reverseOrderOfDescendants() {
     final NodeInfo startNode = findNode("RCURLY");
 
     try (PrecedingIterator iterator = new PrecedingIterator(startNode)) {
@@ -75,7 +75,7 @@ public class PrecedingIteratorTest {
   }
 
   @Test
-  public void testNoSibling() {
+  void noSibling() {
     final NodeInfo startNode = findNode("ANNOTATIONS");
 
     try (PrecedingIterator iterator = new PrecedingIterator(startNode)) {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/xpath/iterators/ReverseDescendantIteratorTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/xpath/iterators/ReverseDescendantIteratorTest.java
@@ -25,10 +25,10 @@ import static com.puppycrawl.tools.checkstyle.internal.utils.XpathIteratorUtil.f
 import net.sf.saxon.om.NodeInfo;
 import org.junit.jupiter.api.Test;
 
-public class ReverseDescendantIteratorTest {
+final class ReverseDescendantIteratorTest {
 
   @Test
-  public void testCorrectOrder() {
+  void correctOrder() {
     final NodeInfo startNode = findNode("CLASS_DEF");
 
     try (ReverseDescendantIterator iterator = new ReverseDescendantIterator(startNode)) {
--- a/src/test/java/com/puppycrawl/tools/checkstyle/xpath/iterators/ReverseListIteratorTest.java
+++ b/src/test/java/com/puppycrawl/tools/checkstyle/xpath/iterators/ReverseListIteratorTest.java
@@ -31,10 +31,10 @@ import net.sf.saxon.om.NodeInfo;
 import net.sf.saxon.om.TreeInfo;
 import org.junit.jupiter.api.Test;
 
-public class ReverseListIteratorTest {
+final class ReverseListIteratorTest {
 
   @Test
-  public void testCorrectOrder() {
+  void correctOrder() {
     final List<AbstractNode> nodes = Arrays.asList(new TestNode(), new TestNode(), new TestNode());
 
     try (ReverseListIterator iterator = new ReverseListIterator(nodes)) {
@@ -46,7 +46,7 @@ public class ReverseListIteratorTest {
   }
 
   @Test
-  public void testNullList() {
+  void nullList() {
     try (ReverseListIterator iterator = new ReverseListIterator(null)) {
       assertWithMessage("Node should be null").that(iterator.next()).isNull();
     }
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/ArrayTypeStyleCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/ArrayTypeStyleCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.ArrayTypeStyleCheck.MSG_KEY
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class ArrayTypeStyleCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class ArrayTypeStyleCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/arraytypestyle";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "14:17: " + getCheckMessage(MSG_KEY), "20:17: " + getCheckMessage(MSG_KEY),
     };
@@ -40,7 +40,7 @@ public class ArrayTypeStyleCheckExamplesTest extends AbstractExamplesModuleTestS
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "15:6: " + getCheckMessage(MSG_KEY), "22:17: " + getCheckMessage(MSG_KEY),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/AvoidEscapedUnicodeCharactersCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/AvoidEscapedUnicodeCharactersCheckExamplesTest.java
@@ -24,7 +24,7 @@ import static com.puppycrawl.tools.checkstyle.checks.AvoidEscapedUnicodeCharacte
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class AvoidEscapedUnicodeCharactersCheckExamplesTest
+final class AvoidEscapedUnicodeCharactersCheckExamplesTest
     extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class AvoidEscapedUnicodeCharactersCheckExamplesTest
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "16:24: " + getCheckMessage(MSG_KEY),
       "18:24: " + getCheckMessage(MSG_KEY),
@@ -45,7 +45,7 @@ public class AvoidEscapedUnicodeCharactersCheckExamplesTest
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "18:24: " + getCheckMessage(MSG_KEY),
       "20:24: " + getCheckMessage(MSG_KEY),
@@ -57,7 +57,7 @@ public class AvoidEscapedUnicodeCharactersCheckExamplesTest
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "18:24: " + getCheckMessage(MSG_KEY),
       "20:24: " + getCheckMessage(MSG_KEY),
@@ -69,7 +69,7 @@ public class AvoidEscapedUnicodeCharactersCheckExamplesTest
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {
       "18:24: " + getCheckMessage(MSG_KEY),
       "22:24: " + getCheckMessage(MSG_KEY),
@@ -80,7 +80,7 @@ public class AvoidEscapedUnicodeCharactersCheckExamplesTest
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {
       "18:24: " + getCheckMessage(MSG_KEY, "unitAbbrev1"),
       "20:24: " + getCheckMessage(MSG_KEY),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/DescendantTokenCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/DescendantTokenCheckExamplesTest.java
@@ -24,119 +24,119 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class DescendantTokenCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class DescendantTokenCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/descendanttoken";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example7.txt"), expected);
   }
 
   @Test
-  public void testExample8() throws Exception {
+  void example8() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example8.txt"), expected);
   }
 
   @Test
-  public void testExample9() throws Exception {
+  void example9() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example9.txt"), expected);
   }
 
   @Test
-  public void testExample10() throws Exception {
+  void example10() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example10.txt"), expected);
   }
 
   @Test
-  public void testExample11() throws Exception {
+  void example11() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example11.txt"), expected);
   }
 
   @Test
-  public void testExample12() throws Exception {
+  void example12() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example12.txt"), expected);
   }
 
   @Test
-  public void testExample13() throws Exception {
+  void example13() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example13.txt"), expected);
   }
 
   @Test
-  public void testExample14() throws Exception {
+  void example14() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example14.txt"), expected);
   }
 
   @Test
-  public void testExample15() throws Exception {
+  void example15() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example15.txt"), expected);
   }
 
   @Test
-  public void testExample16() throws Exception {
+  void example16() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example16.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/FinalParametersCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/FinalParametersCheckExamplesTest.java
@@ -24,28 +24,28 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class FinalParametersCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class FinalParametersCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/finalparameters";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/NewlineAtEndOfFileCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/NewlineAtEndOfFileCheckExamplesTest.java
@@ -26,21 +26,21 @@ import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class NewlineAtEndOfFileCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class NewlineAtEndOfFileCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/newlineatendoffile";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("Example1.java"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "1: " + getCheckMessage(MSG_KEY_NO_NEWLINE_EOF),
     };
@@ -49,7 +49,7 @@ public class NewlineAtEndOfFileCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "1: " + getCheckMessage(MSG_KEY_WRONG_ENDING),
     };
@@ -58,7 +58,7 @@ public class NewlineAtEndOfFileCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {
       "1: " + getCheckMessage(MSG_KEY_NO_NEWLINE_EOF),
     };
@@ -67,7 +67,7 @@ public class NewlineAtEndOfFileCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {
       "1: " + getCheckMessage(MSG_KEY_NO_NEWLINE_EOF),
     };
@@ -76,7 +76,7 @@ public class NewlineAtEndOfFileCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/NoCodeInFileCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/NoCodeInFileCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class NoCodeInFileCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class NoCodeInFileCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/nocodeinfile";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/OrderedPropertiesCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/OrderedPropertiesCheckExamplesTest.java
@@ -24,14 +24,14 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class OrderedPropertiesCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class OrderedPropertiesCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/orderedproperties";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/OuterTypeFilenameCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/OuterTypeFilenameCheckExamplesTest.java
@@ -24,42 +24,42 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class OuterTypeFilenameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class OuterTypeFilenameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/outertypefilename";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/TodoCommentCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/TodoCommentCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class TodoCommentCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class TodoCommentCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/todocomment";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/TrailingCommentCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/TrailingCommentCheckExamplesTest.java
@@ -24,35 +24,35 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class TrailingCommentCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class TrailingCommentCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/trailingcomment";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/TranslationCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/TranslationCheckExamplesTest.java
@@ -24,28 +24,28 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class TranslationCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class TranslationCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/translation";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/UncommentedMainCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/UncommentedMainCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class UncommentedMainCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class UncommentedMainCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/uncommentedmain";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/UniquePropertiesCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/UniquePropertiesCheckExamplesTest.java
@@ -24,28 +24,28 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class UniquePropertiesCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class UniquePropertiesCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/uniqueproperties";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/UpperEllCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/UpperEllCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.UpperEllCheck.MSG_KEY;
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class UpperEllCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class UpperEllCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/upperell";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "13:15: " + getCheckMessage(MSG_KEY, "L"),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/annotation/AnnotationLocationExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/annotation/AnnotationLocationExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.annotation.AnnotationLocati
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class AnnotationLocationExamplesTest extends AbstractExamplesModuleTestSupport {
+final class AnnotationLocationExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/annotation/annotationlocation";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "31:3: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION_ALONE, "SuppressWarnings"),
       "33:3: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION_ALONE, "SuppressWarnings"),
@@ -42,14 +42,14 @@ public class AnnotationLocationExamplesTest extends AbstractExamplesModuleTestSu
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.java"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "24:3: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION_ALONE, "Nonnull"),
       "26:3: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION_ALONE, "Override"),
@@ -61,7 +61,7 @@ public class AnnotationLocationExamplesTest extends AbstractExamplesModuleTestSu
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {
       "33:3: " + getCheckMessage(MSG_KEY_ANNOTATION_LOCATION_ALONE, "SuppressWarnings"),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/annotation/AnnotationOnSameLineCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/annotation/AnnotationOnSameLineCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.annotation.AnnotationOnSame
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class AnnotationOnSameLineCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class AnnotationOnSameLineCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/annotation/annotationonsameline";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "16:3: " + getCheckMessage(MSG_KEY_ANNOTATION_ON_SAME_LINE, "SuppressWarnings"),
       "33:3: " + getCheckMessage(MSG_KEY_ANNOTATION_ON_SAME_LINE, "Override"),
@@ -43,7 +43,7 @@ public class AnnotationOnSameLineCheckExamplesTest extends AbstractExamplesModul
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "25:3: " + getCheckMessage(MSG_KEY_ANNOTATION_ON_SAME_LINE, "SuppressWarnings"),
       "33:3: " + getCheckMessage(MSG_KEY_ANNOTATION_ON_SAME_LINE, "Nullable"),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/annotation/AnnotationUseStyleCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/annotation/AnnotationUseStyleCheckExamplesTest.java
@@ -28,14 +28,14 @@ import static com.puppycrawl.tools.checkstyle.checks.annotation.AnnotationUseSty
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class AnnotationUseStyleCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class AnnotationUseStyleCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/annotation/annotationusestyle";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "25:1: " + getCheckMessage(MSG_KEY_ANNOTATION_INCORRECT_STYLE, "COMPACT_NO_ARRAY"),
       "26:1: " + getCheckMessage(MSG_KEY_ANNOTATION_PARENS_PRESENT),
@@ -46,7 +46,7 @@ public class AnnotationUseStyleCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "16:1: " + getCheckMessage(MSG_KEY_ANNOTATION_INCORRECT_STYLE, "EXPANDED"),
       "19:1: " + getCheckMessage(MSG_KEY_ANNOTATION_INCORRECT_STYLE, "EXPANDED"),
@@ -58,7 +58,7 @@ public class AnnotationUseStyleCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "17:1: " + getCheckMessage(MSG_KEY_ANNOTATION_PARENS_MISSING),
       "25:1: " + getCheckMessage(MSG_KEY_ANNOTATION_INCORRECT_STYLE, "COMPACT"),
@@ -69,7 +69,7 @@ public class AnnotationUseStyleCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {
       "19:34: " + getCheckMessage(MSG_KEY_ANNOTATION_TRAILING_COMMA_MISSING),
       "26:37: " + getCheckMessage(MSG_KEY_ANNOTATION_TRAILING_COMMA_MISSING),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/annotation/MissingDeprecatedCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/annotation/MissingDeprecatedCheckExamplesTest.java
@@ -25,14 +25,14 @@ import static com.puppycrawl.tools.checkstyle.checks.javadoc.AbstractJavadocChec
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class MissingDeprecatedCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class MissingDeprecatedCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/annotation/missingdeprecated";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "18: " + getCheckMessage(MSG_KEY_ANNOTATION_MISSING_DEPRECATED),
     };
@@ -41,7 +41,7 @@ public class MissingDeprecatedCheckExamplesTest extends AbstractExamplesModuleTe
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "20: " + getCheckMessage(MSG_KEY_ANNOTATION_MISSING_DEPRECATED),
       "32: " + getCheckMessage(MSG_KEY_UNCLOSED_HTML_TAG, "p"),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/annotation/MissingOverrideCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/annotation/MissingOverrideCheckExamplesTest.java
@@ -25,7 +25,7 @@ import static com.puppycrawl.tools.checkstyle.checks.annotation.MissingOverrideC
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class MissingOverrideCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class MissingOverrideCheckExamplesTest extends AbstractExamplesModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class MissingOverrideCheckExamplesTest extends AbstractExamplesModuleTest
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "27:3: " + getCheckMessage(MSG_KEY_ANNOTATION_MISSING_OVERRIDE, "test2"),
       "33:3: " + getCheckMessage(MSG_KEY_TAG_NOT_VALID_ON, "{@inheritDoc}"),
@@ -43,7 +43,7 @@ public class MissingOverrideCheckExamplesTest extends AbstractExamplesModuleTest
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "22:3: " + getCheckMessage(MSG_KEY_ANNOTATION_MISSING_OVERRIDE, "equals"),
       "30:3: " + getCheckMessage(MSG_KEY_ANNOTATION_MISSING_OVERRIDE, "test"),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/annotation/PackageAnnotationCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/annotation/PackageAnnotationCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.annotation.PackageAnnotatio
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class PackageAnnotationCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class PackageAnnotationCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/annotation/packageannotation";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "13:1: " + getCheckMessage(MSG_KEY),
     };
@@ -40,14 +40,14 @@ public class PackageAnnotationCheckExamplesTest extends AbstractExamplesModuleTe
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.java"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("example3/package-info.java"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/annotation/SuppressWarningsCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/annotation/SuppressWarningsCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.annotation.SuppressWarnings
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class SuppressWarningsCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class SuppressWarningsCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/annotation/suppresswarnings";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "13:19: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, ""),
       "16:21: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, ""),
@@ -41,7 +41,7 @@ public class SuppressWarningsCheckExamplesTest extends AbstractExamplesModuleTes
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "40:21: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unused"),
       "44:32: " + getCheckMessage(MSG_KEY_SUPPRESSED_WARNING_NOT_ALLOWED, "unused"),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/annotation/SuppressWarningsHolderExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/annotation/SuppressWarningsHolderExamplesTest.java
@@ -27,14 +27,14 @@ import com.puppycrawl.tools.checkstyle.checks.sizes.ParameterNumberCheck;
 import com.puppycrawl.tools.checkstyle.checks.whitespace.NoWhitespaceAfterCheck;
 import org.junit.jupiter.api.Test;
 
-public class SuppressWarningsHolderExamplesTest extends AbstractExamplesModuleTestSupport {
+final class SuppressWarningsHolderExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/annotation/suppresswarningsholder";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String pattern1 = "^[a-z][a-zA-Z0-9]*$";
     final String pattern2 = "^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$";
     final String[] expected = {
@@ -55,7 +55,7 @@ public class SuppressWarningsHolderExamplesTest extends AbstractExamplesModuleTe
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "19:15: " + getCheckMessage(ParameterNumberCheck.class, ParameterNumberCheck.MSG_KEY, 7, 8),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/blocks/AvoidNestedBlocksCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/blocks/AvoidNestedBlocksCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.blocks.AvoidNestedBlocksChe
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class AvoidNestedBlocksCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class AvoidNestedBlocksCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/blocks/avoidnestedblocks";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "17:5: " + getCheckMessage(MSG_KEY_BLOCK_NESTED),
       "23:15: " + getCheckMessage(MSG_KEY_BLOCK_NESTED),
@@ -41,7 +41,7 @@ public class AvoidNestedBlocksCheckExamplesTest extends AbstractExamplesModuleTe
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "19:5: " + getCheckMessage(MSG_KEY_BLOCK_NESTED),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/blocks/EmptyBlockCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/blocks/EmptyBlockCheckExamplesTest.java
@@ -25,14 +25,14 @@ import static com.puppycrawl.tools.checkstyle.checks.blocks.EmptyBlockCheck.MSG_
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class EmptyBlockCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class EmptyBlockCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/blocks/emptyblock";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "14:34: " + getCheckMessage(MSG_KEY_BLOCK_NO_STATEMENT, "for"),
       "17:9: " + getCheckMessage(MSG_KEY_BLOCK_NO_STATEMENT, "try"),
@@ -42,7 +42,7 @@ public class EmptyBlockCheckExamplesTest extends AbstractExamplesModuleTestSuppo
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "21:9: " + getCheckMessage(MSG_KEY_BLOCK_EMPTY, "try"),
     };
@@ -51,7 +51,7 @@ public class EmptyBlockCheckExamplesTest extends AbstractExamplesModuleTestSuppo
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "24:16: " + getCheckMessage(MSG_KEY_BLOCK_NO_STATEMENT, "default"),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/blocks/EmptyCatchBlockCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/blocks/EmptyCatchBlockCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.blocks.EmptyCatchBlockCheck
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class EmptyCatchBlockCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class EmptyCatchBlockCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/blocks/emptycatchblock";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "16:41: " + getCheckMessage(MSG_KEY_CATCH_BLOCK_EMPTY),
       "31:34: " + getCheckMessage(MSG_KEY_CATCH_BLOCK_EMPTY),
@@ -41,7 +41,7 @@ public class EmptyCatchBlockCheckExamplesTest extends AbstractExamplesModuleTest
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "33:34: " + getCheckMessage(MSG_KEY_CATCH_BLOCK_EMPTY),
     };
@@ -50,7 +50,7 @@ public class EmptyCatchBlockCheckExamplesTest extends AbstractExamplesModuleTest
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "18:41: " + getCheckMessage(MSG_KEY_CATCH_BLOCK_EMPTY),
       "25:39: " + getCheckMessage(MSG_KEY_CATCH_BLOCK_EMPTY),
@@ -61,7 +61,7 @@ public class EmptyCatchBlockCheckExamplesTest extends AbstractExamplesModuleTest
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {
       "51:34: " + getCheckMessage(MSG_KEY_CATCH_BLOCK_EMPTY),
     };
@@ -70,7 +70,7 @@ public class EmptyCatchBlockCheckExamplesTest extends AbstractExamplesModuleTest
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {
       "18:34: " + getCheckMessage(MSG_KEY_CATCH_BLOCK_EMPTY),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/blocks/LeftCurlyCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/blocks/LeftCurlyCheckExamplesTest.java
@@ -26,14 +26,14 @@ import static com.puppycrawl.tools.checkstyle.checks.blocks.LeftCurlyCheck.MSG_K
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class LeftCurlyCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class LeftCurlyCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/blocks/leftcurly";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "13:1: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", "1"),
       "15:3: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", "3"),
@@ -43,7 +43,7 @@ public class LeftCurlyCheckExamplesTest extends AbstractExamplesModuleTestSuppor
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "23:13: " + getCheckMessage(MSG_KEY_LINE_NEW, "{", "13"),
     };
@@ -52,7 +52,7 @@ public class LeftCurlyCheckExamplesTest extends AbstractExamplesModuleTestSuppor
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "16:1: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", "1"),
       "22:13: " + getCheckMessage(MSG_KEY_LINE_NEW, "{", "13"),
@@ -62,7 +62,7 @@ public class LeftCurlyCheckExamplesTest extends AbstractExamplesModuleTestSuppor
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {
       "15:1: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", "1"),
       "17:3: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", "3"),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/blocks/NeedBracesCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/blocks/NeedBracesCheckExamplesTest.java
@@ -25,14 +25,14 @@ import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class NeedBracesCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class NeedBracesCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/blocks/needbraces";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "20:5: " + getCheckMessage(MSG_KEY_NEED_BRACES, "if"),
       "24:7: " + getCheckMessage(MSG_KEY_NEED_BRACES, "else"),
@@ -47,7 +47,7 @@ public class NeedBracesCheckExamplesTest extends AbstractExamplesModuleTestSuppo
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "22:5: " + getCheckMessage(MSG_KEY_NEED_BRACES, "if"),
       "26:7: " + getCheckMessage(MSG_KEY_NEED_BRACES, "else"),
@@ -57,7 +57,7 @@ public class NeedBracesCheckExamplesTest extends AbstractExamplesModuleTestSuppo
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "33:5: " + getCheckMessage(MSG_KEY_NEED_BRACES, "do"),
       "40:5: " + getCheckMessage(MSG_KEY_NEED_BRACES, "while"),
@@ -67,14 +67,14 @@ public class NeedBracesCheckExamplesTest extends AbstractExamplesModuleTestSuppo
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("Example4.java"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {
       "39:5: " + getCheckMessage(MSG_KEY_NEED_BRACES, "while"),
     };
@@ -83,7 +83,7 @@ public class NeedBracesCheckExamplesTest extends AbstractExamplesModuleTestSuppo
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {
       "24:38: " + getCheckMessage(MSG_KEY_NEED_BRACES, "->"),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/blocks/RightCurlyCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/blocks/RightCurlyCheckExamplesTest.java
@@ -25,14 +25,14 @@ import static com.puppycrawl.tools.checkstyle.checks.blocks.RightCurlyCheck.MSG_
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class RightCurlyCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class RightCurlyCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/blocks/rightcurly";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "19:5: " + getCheckMessage(MSG_KEY_LINE_SAME, "}", "5"),
       "32:23: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", "23"),
@@ -43,7 +43,7 @@ public class RightCurlyCheckExamplesTest extends AbstractExamplesModuleTestSuppo
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "22:21: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", "21"),
       "43:47: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", "47"),
@@ -53,7 +53,7 @@ public class RightCurlyCheckExamplesTest extends AbstractExamplesModuleTestSuppo
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "35:16: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", "16"),
     };
@@ -62,7 +62,7 @@ public class RightCurlyCheckExamplesTest extends AbstractExamplesModuleTestSuppo
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {
       "22:5: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", "5"),
     };
@@ -71,7 +71,7 @@ public class RightCurlyCheckExamplesTest extends AbstractExamplesModuleTestSuppo
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {
       "41:16: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", "16"),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/ArrayTrailingCommaCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/ArrayTrailingCommaCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.ArrayTrailingCommaCh
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class ArrayTrailingCommaCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class ArrayTrailingCommaCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/arraytrailingcomma";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "17:5: " + getCheckMessage(MSG_KEY), "25:5: " + getCheckMessage(MSG_KEY),
     };
@@ -40,7 +40,7 @@ public class ArrayTrailingCommaCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "15:26: " + getCheckMessage(MSG_KEY),
       "19:5: " + getCheckMessage(MSG_KEY),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/AvoidDoubleBraceInitializationCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/AvoidDoubleBraceInitializationCheckExamplesTest.java
@@ -24,7 +24,7 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class AvoidDoubleBraceInitializationCheckExamplesTest
+final class AvoidDoubleBraceInitializationCheckExamplesTest
     extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
@@ -32,14 +32,14 @@ public class AvoidDoubleBraceInitializationCheckExamplesTest
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/AvoidInlineConditionalsCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/AvoidInlineConditionalsCheckExamplesTest.java
@@ -24,14 +24,14 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class AvoidInlineConditionalsCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class AvoidInlineConditionalsCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/avoidinlineconditionals";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/AvoidNoArgumentSuperConstructorCallCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/AvoidNoArgumentSuperConstructorCallCheckExamplesTest.java
@@ -24,7 +24,7 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class AvoidNoArgumentSuperConstructorCallCheckExamplesTest
+final class AvoidNoArgumentSuperConstructorCallCheckExamplesTest
     extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class AvoidNoArgumentSuperConstructorCallCheckExamplesTest
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/CovariantEqualsCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/CovariantEqualsCheckExamplesTest.java
@@ -24,35 +24,35 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class CovariantEqualsCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class CovariantEqualsCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/covariantequals";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/DeclarationOrderCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/DeclarationOrderCheckExamplesTest.java
@@ -24,28 +24,28 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class DeclarationOrderCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class DeclarationOrderCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/declarationorder";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/DefaultComesLastCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/DefaultComesLastCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class DefaultComesLastCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class DefaultComesLastCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/defaultcomeslast";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/EmptyStatementCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/EmptyStatementCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.EmptyStatementCheck.
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class EmptyStatementCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class EmptyStatementCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/emptystatement";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "15:14: " + getCheckMessage(MSG_KEY), "17:28: " + getCheckMessage(MSG_KEY),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/EqualsAvoidNullCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/EqualsAvoidNullCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class EqualsAvoidNullCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class EqualsAvoidNullCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/equalsavoidnull";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/EqualsHashCodeCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/EqualsHashCodeCheckExamplesTest.java
@@ -24,14 +24,14 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class EqualsHashCodeCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class EqualsHashCodeCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/equalshashcode";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/ExplicitInitializationCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/ExplicitInitializationCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class ExplicitInitializationCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class ExplicitInitializationCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/explicitinitialization";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/FallThroughCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/FallThroughCheckExamplesTest.java
@@ -25,7 +25,7 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.FallThroughCheck.MSG
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class FallThroughCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class FallThroughCheckExamplesTest extends AbstractExamplesModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class FallThroughCheckExamplesTest extends AbstractExamplesModuleTestSupp
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "21:9: " + getCheckMessage(MSG_FALL_THROUGH), "32:9: " + getCheckMessage(MSG_FALL_THROUGH),
     };
@@ -42,7 +42,7 @@ public class FallThroughCheckExamplesTest extends AbstractExamplesModuleTestSupp
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "23:9: " + getCheckMessage(MSG_FALL_THROUGH),
       "34:9: " + getCheckMessage(MSG_FALL_THROUGH),
@@ -53,7 +53,7 @@ public class FallThroughCheckExamplesTest extends AbstractExamplesModuleTestSupp
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "23:9: " + getCheckMessage(MSG_FALL_THROUGH),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/FinalLocalVariableCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/FinalLocalVariableCheckExamplesTest.java
@@ -24,7 +24,7 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class FinalLocalVariableCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class FinalLocalVariableCheckExamplesTest extends AbstractExamplesModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,28 +32,28 @@ public class FinalLocalVariableCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/HiddenFieldCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/HiddenFieldCheckExamplesTest.java
@@ -24,56 +24,56 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class HiddenFieldCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class HiddenFieldCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/hiddenfield";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example7.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalCatchCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalCatchCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class IllegalCatchCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class IllegalCatchCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/illegalcatch";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalInstantiationCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalInstantiationCheckExamplesTest.java
@@ -24,28 +24,28 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class IllegalInstantiationCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class IllegalInstantiationCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/illegalinstantiation";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalThrowsCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalThrowsCheckExamplesTest.java
@@ -24,35 +24,35 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class IllegalThrowsCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class IllegalThrowsCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/illegalthrows";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalTokenCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalTokenCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class IllegalTokenCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class IllegalTokenCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/illegaltoken";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalTokenTextCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalTokenTextCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.IllegalTokenTextChec
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class IllegalTokenTextCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class IllegalTokenTextCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/illegaltokentext";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "17:20: " + getCheckMessage(MSG_KEY, "a href"),
     };
@@ -40,7 +40,7 @@ public class IllegalTokenTextCheckExamplesTest extends AbstractExamplesModuleTes
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "18:20: " + getCheckMessage(MSG_KEY, "a href"),
       "19:20: " + getCheckMessage(MSG_KEY, "a href"),
@@ -50,7 +50,7 @@ public class IllegalTokenTextCheckExamplesTest extends AbstractExamplesModuleTes
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "17:29: " + getCheckMessage(MSG_KEY, '"'),
     };
@@ -59,7 +59,7 @@ public class IllegalTokenTextCheckExamplesTest extends AbstractExamplesModuleTes
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {
       "21:17: " + getCheckMessage(MSG_KEY, "^0[^lx]"),
       "23:18: " + getCheckMessage(MSG_KEY, "^0[^lx]"),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalTypeCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalTypeCheckExamplesTest.java
@@ -24,56 +24,56 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class IllegalTypeCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class IllegalTypeCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/illegaltype";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example7.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/InnerAssignmentCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/InnerAssignmentCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.InnerAssignmentCheck
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class InnerAssignmentCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class InnerAssignmentCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/innerassignment";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "21:11: " + getCheckMessage(MSG_KEY),
       "22:11: " + getCheckMessage(MSG_KEY),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/MagicNumberCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/MagicNumberCheckExamplesTest.java
@@ -24,49 +24,49 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class MagicNumberCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class MagicNumberCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/magicnumber";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/MatchXpathCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/MatchXpathCheckExamplesTest.java
@@ -24,35 +24,35 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class MatchXpathCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class MatchXpathCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/matchxpath";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/MissingCtorCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/MissingCtorCheckExamplesTest.java
@@ -24,14 +24,14 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class MissingCtorCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class MissingCtorCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/missingctor";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/MissingSwitchDefaultCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/MissingSwitchDefaultCheckExamplesTest.java
@@ -24,28 +24,28 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class MissingSwitchDefaultCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class MissingSwitchDefaultCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/missingswitchdefault";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/ModifiedControlVariableCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/ModifiedControlVariableCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class ModifiedControlVariableCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class ModifiedControlVariableCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/modifiedcontrolvariable";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/MultipleStringLiteralsCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/MultipleStringLiteralsCheckExamplesTest.java
@@ -24,35 +24,35 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class MultipleStringLiteralsCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class MultipleStringLiteralsCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/multiplestringliterals";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/MultipleVariableDeclarationsCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/MultipleVariableDeclarationsCheckExamplesTest.java
@@ -24,7 +24,7 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class MultipleVariableDeclarationsCheckExamplesTest
+final class MultipleVariableDeclarationsCheckExamplesTest
     extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class MultipleVariableDeclarationsCheckExamplesTest
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/NestedForDepthCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/NestedForDepthCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class NestedForDepthCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class NestedForDepthCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/nestedfordepth";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/NestedIfDepthCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/NestedIfDepthCheckExamplesTest.java
@@ -24,35 +24,35 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class NestedIfDepthCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class NestedIfDepthCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/nestedifdepth";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/NestedTryDepthCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/NestedTryDepthCheckExamplesTest.java
@@ -24,42 +24,42 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class NestedTryDepthCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class NestedTryDepthCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/nestedtrydepth";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/NoArrayTrailingCommaCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/NoArrayTrailingCommaCheckExamplesTest.java
@@ -24,14 +24,14 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class NoArrayTrailingCommaCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class NoArrayTrailingCommaCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/noarraytrailingcomma";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/NoCloneCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/NoCloneCheckExamplesTest.java
@@ -24,14 +24,14 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class NoCloneCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class NoCloneCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/noclone";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/NoEnumTrailingCommaCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/NoEnumTrailingCommaCheckExamplesTest.java
@@ -24,14 +24,14 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class NoEnumTrailingCommaCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class NoEnumTrailingCommaCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/noenumtrailingcomma";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/NoFinalizerCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/NoFinalizerCheckExamplesTest.java
@@ -24,14 +24,14 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class NoFinalizerCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class NoFinalizerCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/nofinalizer";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/OneStatementPerLineCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/OneStatementPerLineCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class OneStatementPerLineCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class OneStatementPerLineCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/onestatementperline";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/OverloadMethodsDeclarationOrderCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/OverloadMethodsDeclarationOrderCheckExamplesTest.java
@@ -24,7 +24,7 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class OverloadMethodsDeclarationOrderCheckExamplesTest
+final class OverloadMethodsDeclarationOrderCheckExamplesTest
     extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
@@ -32,14 +32,14 @@ public class OverloadMethodsDeclarationOrderCheckExamplesTest
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/PackageDeclarationCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/PackageDeclarationCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class PackageDeclarationCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class PackageDeclarationCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/packagedeclaration";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/ParameterAssignmentCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/ParameterAssignmentCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.ParameterAssignmentC
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class ParameterAssignmentCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class ParameterAssignmentCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/parameterassignment";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "21:15: " + getCheckMessage(MSG_KEY, "parameter"),
       "34:27: " + getCheckMessage(MSG_KEY, "a"),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/RequireThisCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/RequireThisCheckExamplesTest.java
@@ -24,49 +24,49 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class RequireThisCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class RequireThisCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/requirethis";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/ReturnCountCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/ReturnCountCheckExamplesTest.java
@@ -24,42 +24,42 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class ReturnCountCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class ReturnCountCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/returncount";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/SimplifyBooleanExpressionCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/SimplifyBooleanExpressionCheckExamplesTest.java
@@ -24,14 +24,14 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class SimplifyBooleanExpressionCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class SimplifyBooleanExpressionCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/simplifybooleanexpression";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/SimplifyBooleanReturnCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/SimplifyBooleanReturnCheckExamplesTest.java
@@ -24,14 +24,14 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class SimplifyBooleanReturnCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class SimplifyBooleanReturnCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/simplifybooleanreturn";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/StringLiteralEqualityCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/StringLiteralEqualityCheckExamplesTest.java
@@ -24,14 +24,14 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class StringLiteralEqualityCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class StringLiteralEqualityCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/stringliteralequality";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/SuperCloneCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/SuperCloneCheckExamplesTest.java
@@ -24,7 +24,7 @@ import static com.puppycrawl.tools.checkstyle.checks.coding.AbstractSuperCheck.M
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class SuperCloneCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class SuperCloneCheckExamplesTest extends AbstractExamplesModuleTestSupport {
 
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class SuperCloneCheckExamplesTest extends AbstractExamplesModuleTestSuppo
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "22:22: " + getCheckMessage(MSG_KEY, "clone"),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/SuperFinalizeCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/SuperFinalizeCheckExamplesTest.java
@@ -24,14 +24,14 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class SuperFinalizeCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class SuperFinalizeCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/superfinalize";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessaryParenthesesCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessaryParenthesesCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class UnnecessaryParenthesesCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class UnnecessaryParenthesesCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/unnecessaryparentheses";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessarySemicolonAfterOuterTypeDeclarationCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessarySemicolonAfterOuterTypeDeclarationCheckExamplesTest.java
@@ -24,7 +24,7 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class UnnecessarySemicolonAfterOuterTypeDeclarationCheckExamplesTest
+final class UnnecessarySemicolonAfterOuterTypeDeclarationCheckExamplesTest
     extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
@@ -33,14 +33,14 @@ public class UnnecessarySemicolonAfterOuterTypeDeclarationCheckExamplesTest
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessarySemicolonAfterTypeMemberDeclarationCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessarySemicolonAfterTypeMemberDeclarationCheckExamplesTest.java
@@ -24,7 +24,7 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class UnnecessarySemicolonAfterTypeMemberDeclarationCheckExamplesTest
+final class UnnecessarySemicolonAfterTypeMemberDeclarationCheckExamplesTest
     extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class UnnecessarySemicolonAfterTypeMemberDeclarationCheckExamplesTest
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessarySemicolonInEnumerationCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessarySemicolonInEnumerationCheckExamplesTest.java
@@ -24,7 +24,7 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class UnnecessarySemicolonInEnumerationCheckExamplesTest
+final class UnnecessarySemicolonInEnumerationCheckExamplesTest
     extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
@@ -32,14 +32,14 @@ public class UnnecessarySemicolonInEnumerationCheckExamplesTest
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessarySemicolonInTryWithResourcesCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessarySemicolonInTryWithResourcesCheckExamplesTest.java
@@ -24,7 +24,7 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class UnnecessarySemicolonInTryWithResourcesCheckExamplesTest
+final class UnnecessarySemicolonInTryWithResourcesCheckExamplesTest
     extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
@@ -33,14 +33,14 @@ public class UnnecessarySemicolonInTryWithResourcesCheckExamplesTest
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/UnusedLocalVariableCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/UnusedLocalVariableCheckExamplesTest.java
@@ -24,14 +24,14 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class UnusedLocalVariableCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class UnusedLocalVariableCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/coding/unusedlocalvariable";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/VariableDeclarationUsageDistanceCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/coding/VariableDeclarationUsageDistanceCheckExamplesTest.java
@@ -24,7 +24,7 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class VariableDeclarationUsageDistanceCheckExamplesTest
+final class VariableDeclarationUsageDistanceCheckExamplesTest
     extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
@@ -32,35 +32,35 @@ public class VariableDeclarationUsageDistanceCheckExamplesTest
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/design/DesignForExtensionCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/design/DesignForExtensionCheckExamplesTest.java
@@ -24,35 +24,35 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class DesignForExtensionCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class DesignForExtensionCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/design/designforextension";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/design/FinalClassCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/design/FinalClassCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.design.FinalClassCheck.MSG_
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class FinalClassCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class FinalClassCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/design/finalclass";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "19:3: " + getCheckMessage(MSG_KEY, "B"), "50:5: " + getCheckMessage(MSG_KEY, "Class2"),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/design/HideUtilityClassConstructorCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/design/HideUtilityClassConstructorCheckExamplesTest.java
@@ -24,15 +24,14 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class HideUtilityClassConstructorCheckExamplesTest
-    extends AbstractExamplesModuleTestSupport {
+final class HideUtilityClassConstructorCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/design/hideutilityclassconstructor";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/design/InnerTypeLastCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/design/InnerTypeLastCheckExamplesTest.java
@@ -24,14 +24,14 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class InnerTypeLastCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class InnerTypeLastCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/design/innertypelast";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/design/InterfaceIsTypeCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/design/InterfaceIsTypeCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.design.InterfaceIsTypeCheck
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class InterfaceIsTypeCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class InterfaceIsTypeCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/design/interfaceistype";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "14:3: " + getCheckMessage(MSG_KEY),
     };
@@ -40,7 +40,7 @@ public class InterfaceIsTypeCheckExamplesTest extends AbstractExamplesModuleTest
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "16:3: " + getCheckMessage(MSG_KEY), "21:3: " + getCheckMessage(MSG_KEY),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/design/MutableExceptionCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/design/MutableExceptionCheckExamplesTest.java
@@ -24,28 +24,28 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class MutableExceptionCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class MutableExceptionCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/design/mutableexception";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/design/OneTopLevelClassCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/design/OneTopLevelClassCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class OneTopLevelClassCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class OneTopLevelClassCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/design/onetoplevelclass";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/design/ThrowsCountCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/design/ThrowsCountCheckExamplesTest.java
@@ -24,28 +24,28 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class ThrowsCountCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class ThrowsCountCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/design/throwscount";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/design/VisibilityModifierCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/design/VisibilityModifierCheckExamplesTest.java
@@ -25,14 +25,14 @@ import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class VisibilityModifierCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class VisibilityModifierCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/design/visibilitymodifier";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "23:7: " + getCheckMessage(MSG_KEY, "field1"),
       "25:20: " + getCheckMessage(MSG_KEY, "field2"),
@@ -50,7 +50,7 @@ public class VisibilityModifierCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "27:20: " + getCheckMessage(MSG_KEY, "field2"),
       "30:14: " + getCheckMessage(MSG_KEY, "field3"),
@@ -65,7 +65,7 @@ public class VisibilityModifierCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "25:7: " + getCheckMessage(MSG_KEY, "field1"),
       "30:14: " + getCheckMessage(MSG_KEY, "field3"),
@@ -82,7 +82,7 @@ public class VisibilityModifierCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {
       "25:7: " + getCheckMessage(MSG_KEY, "field1"),
       "27:20: " + getCheckMessage(MSG_KEY, "field2"),
@@ -101,7 +101,7 @@ public class VisibilityModifierCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {
       "25:7: " + getCheckMessage(MSG_KEY, "field1"),
       "27:20: " + getCheckMessage(MSG_KEY, "field2"),
@@ -119,7 +119,7 @@ public class VisibilityModifierCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {
       "28:7: " + getCheckMessage(MSG_KEY, "field1"),
       "30:20: " + getCheckMessage(MSG_KEY, "field2"),
@@ -137,7 +137,7 @@ public class VisibilityModifierCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {
       "28:7: " + getCheckMessage(MSG_KEY, "field1"),
       "30:20: " + getCheckMessage(MSG_KEY, "field2"),
@@ -155,7 +155,7 @@ public class VisibilityModifierCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample8() throws Exception {
+  void example8() throws Exception {
     final String[] expected = {
       "26:7: " + getCheckMessage(MSG_KEY, "field1"),
       "28:20: " + getCheckMessage(MSG_KEY, "field2"),
@@ -172,7 +172,7 @@ public class VisibilityModifierCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample9() throws Exception {
+  void example9() throws Exception {
     final String[] expected = {
       "23:7: " + getCheckMessage(MSG_KEY, "field1"),
       "25:20: " + getCheckMessage(MSG_KEY, "field2"),
@@ -190,7 +190,7 @@ public class VisibilityModifierCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample10() throws Exception {
+  void example10() throws Exception {
     final String[] expected = {
       "25:7: " + getCheckMessage(MSG_KEY, "field1"),
       "27:20: " + getCheckMessage(MSG_KEY, "field2"),
@@ -208,7 +208,7 @@ public class VisibilityModifierCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample11() throws Exception {
+  void example11() throws Exception {
     final String[] expected = {
       "22:20: " + getCheckMessage(MSG_KEY, "someIntValue"),
       "24:37: " + getCheckMessage(MSG_KEY, "includes"),
@@ -221,7 +221,7 @@ public class VisibilityModifierCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample12() throws Exception {
+  void example12() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("Example12.java"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/header/HeaderCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/header/HeaderCheckExamplesTest.java
@@ -24,28 +24,28 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class HeaderCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class HeaderCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/header/header";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/header/RegexpHeaderCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/header/RegexpHeaderCheckExamplesTest.java
@@ -24,42 +24,42 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class RegexpHeaderCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class RegexpHeaderCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/header/regexpheader";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/imports/AvoidStarImportCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/imports/AvoidStarImportCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.imports.AvoidStarImportChec
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class AvoidStarImportCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class AvoidStarImportCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/imports/avoidstarimport";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "13:15: " + getCheckMessage(MSG_KEY, "java.io.*"),
       "14:29: " + getCheckMessage(MSG_KEY, "java.lang.Math.*"),
@@ -43,7 +43,7 @@ public class AvoidStarImportCheckExamplesTest extends AbstractExamplesModuleTest
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "17:17: " + getCheckMessage(MSG_KEY, "java.util.*"),
     };
@@ -52,7 +52,7 @@ public class AvoidStarImportCheckExamplesTest extends AbstractExamplesModuleTest
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "16:29: " + getCheckMessage(MSG_KEY, "java.lang.Math.*"),
     };
@@ -61,7 +61,7 @@ public class AvoidStarImportCheckExamplesTest extends AbstractExamplesModuleTest
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {
       "15:15: " + getCheckMessage(MSG_KEY, "java.io.*"),
       "17:17: " + getCheckMessage(MSG_KEY, "java.util.*"),
@@ -72,7 +72,7 @@ public class AvoidStarImportCheckExamplesTest extends AbstractExamplesModuleTest
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {
       "17:29: " + getCheckMessage(MSG_KEY, "java.lang.Math.*"),
     };
@@ -81,7 +81,7 @@ public class AvoidStarImportCheckExamplesTest extends AbstractExamplesModuleTest
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {
       "18:17: " + getCheckMessage(MSG_KEY, "java.util.*"),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/imports/AvoidStaticImportCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/imports/AvoidStaticImportCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.imports.AvoidStaticImportCh
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class AvoidStaticImportCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class AvoidStaticImportCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/imports/avoidstaticimport";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "12:29: " + getCheckMessage(MSG_KEY, "java.lang.Math.pow"),
       "13:31: " + getCheckMessage(MSG_KEY, "java.lang.System.*"),
@@ -41,7 +41,7 @@ public class AvoidStaticImportCheckExamplesTest extends AbstractExamplesModuleTe
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "16:32: " + getCheckMessage(MSG_KEY, "java.lang.Integer.parseInt"),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/imports/CustomImportOrderCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/imports/CustomImportOrderCheckExamplesTest.java
@@ -24,112 +24,112 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class CustomImportOrderCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class CustomImportOrderCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/imports/customimportorder";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example7.txt"), expected);
   }
 
   @Test
-  public void testExample8() throws Exception {
+  void example8() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example8.txt"), expected);
   }
 
   @Test
-  public void testExample9() throws Exception {
+  void example9() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example9.txt"), expected);
   }
 
   @Test
-  public void testExample10() throws Exception {
+  void example10() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example10.txt"), expected);
   }
 
   @Test
-  public void testExample11() throws Exception {
+  void example11() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example11.txt"), expected);
   }
 
   @Test
-  public void testExample12() throws Exception {
+  void example12() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example12.txt"), expected);
   }
 
   @Test
-  public void testExample13() throws Exception {
+  void example13() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example13.txt"), expected);
   }
 
   @Test
-  public void testExample14() throws Exception {
+  void example14() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example14.txt"), expected);
   }
 
   @Test
-  public void testExample15() throws Exception {
+  void example15() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example15.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/imports/IllegalImportCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/imports/IllegalImportCheckExamplesTest.java
@@ -24,70 +24,70 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class IllegalImportCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class IllegalImportCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/imports/illegalimport";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example7.txt"), expected);
   }
 
   @Test
-  public void testExample8() throws Exception {
+  void example8() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example8.txt"), expected);
   }
 
   @Test
-  public void testExample9() throws Exception {
+  void example9() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example9.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/imports/ImportOrderCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/imports/ImportOrderCheckExamplesTest.java
@@ -24,91 +24,91 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class ImportOrderCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class ImportOrderCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/imports/importorder";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example7.txt"), expected);
   }
 
   @Test
-  public void testExample8() throws Exception {
+  void example8() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example8.txt"), expected);
   }
 
   @Test
-  public void testExample9() throws Exception {
+  void example9() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example9.txt"), expected);
   }
 
   @Test
-  public void testExample10() throws Exception {
+  void example10() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example10.txt"), expected);
   }
 
   @Test
-  public void testExample11() throws Exception {
+  void example11() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example11.txt"), expected);
   }
 
   @Test
-  public void testExample12() throws Exception {
+  void example12() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example12.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/imports/RedundantImportCheckExamplesTest.java
@@ -26,14 +26,14 @@ import static com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportChec
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class RedundantImportCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class RedundantImportCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/imports/redundantimport";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "16:1: "
           + getCheckMessage(
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/imports/UnusedImportsCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/imports/UnusedImportsCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.imports.UnusedImportsCheck.
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class UnusedImportsCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class UnusedImportsCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/imports/unusedimports";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "19:8: " + getCheckMessage(MSG_KEY, "java.lang.String"),
       "22:8: " + getCheckMessage(MSG_KEY, "java.util.Map"),
@@ -41,7 +41,7 @@ public class UnusedImportsCheckExamplesTest extends AbstractExamplesModuleTestSu
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "21:8: " + getCheckMessage(MSG_KEY, "java.lang.String"),
       "24:8: " + getCheckMessage(MSG_KEY, "java.util.Map"),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/indentation/CommentsIndentationCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/indentation/CommentsIndentationCheckExamplesTest.java
@@ -24,77 +24,77 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class CommentsIndentationCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class CommentsIndentationCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/indentation/commentsindentation";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example7.txt"), expected);
   }
 
   @Test
-  public void testExample8() throws Exception {
+  void example8() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example8.txt"), expected);
   }
 
   @Test
-  public void testExample9() throws Exception {
+  void example9() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example9.txt"), expected);
   }
 
   @Test
-  public void testExample10() throws Exception {
+  void example10() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example10.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/indentation/IndentationCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/indentation/IndentationCheckExamplesTest.java
@@ -24,35 +24,35 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class IndentationCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class IndentationCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/indentation/indentation";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/AtclauseOrderCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/AtclauseOrderCheckExamplesTest.java
@@ -24,14 +24,14 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class AtclauseOrderCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class AtclauseOrderCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/javadoc/atclauseorder";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/InvalidJavadocPositionCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/InvalidJavadocPositionCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.javadoc.InvalidJavadocPosit
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class InvalidJavadocPositionCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class InvalidJavadocPositionCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/javadoc/invalidjavadocposition";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "14:1: " + getCheckMessage(MSG_KEY),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocBlockTagLocationCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocBlockTagLocationCheckExamplesTest.java
@@ -22,28 +22,28 @@ package com.puppycrawl.tools.checkstyle.checks.javadoc;
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class JavadocBlockTagLocationCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class JavadocBlockTagLocationCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/javadoc/javadocblocktaglocation";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.java"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.java"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.java"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocContentLocationCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocContentLocationCheckExamplesTest.java
@@ -25,14 +25,14 @@ import static com.puppycrawl.tools.checkstyle.checks.javadoc.JavadocContentLocat
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class JavadocContentLocationCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class JavadocContentLocationCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/javadoc/javadoccontentlocation";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "15:3: " + getCheckMessage(MSG_JAVADOC_CONTENT_SECOND_LINE),
     };
@@ -41,7 +41,7 @@ public class JavadocContentLocationCheckExamplesTest extends AbstractExamplesMod
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "22:3: " + getCheckMessage(MSG_JAVADOC_CONTENT_FIRST_LINE),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocMethodCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocMethodCheckExamplesTest.java
@@ -24,56 +24,56 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class JavadocMethodCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class JavadocMethodCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/javadoc/javadocmethod";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example7.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocMissingLeadingAsteriskCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocMissingLeadingAsteriskCheckExamplesTest.java
@@ -24,7 +24,7 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class JavadocMissingLeadingAsteriskCheckExamplesTest
+final class JavadocMissingLeadingAsteriskCheckExamplesTest
     extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class JavadocMissingLeadingAsteriskCheckExamplesTest
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocMissingWhitespaceAfterAsteriskCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocMissingWhitespaceAfterAsteriskCheckExamplesTest.java
@@ -24,7 +24,7 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class JavadocMissingWhitespaceAfterAsteriskCheckExamplesTest
+final class JavadocMissingWhitespaceAfterAsteriskCheckExamplesTest
     extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class JavadocMissingWhitespaceAfterAsteriskCheckExamplesTest
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocPackageCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocPackageCheckExamplesTest.java
@@ -24,14 +24,14 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class JavadocPackageCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class JavadocPackageCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/javadoc/javadocpackage";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocParagraphCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocParagraphCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class JavadocParagraphCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class JavadocParagraphCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/javadoc/javadocparagraph";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocStyleCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocStyleCheckExamplesTest.java
@@ -24,49 +24,49 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class JavadocStyleCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class JavadocStyleCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/javadoc/javadocstyle";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocTagContinuationIndentationCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocTagContinuationIndentationCheckExamplesTest.java
@@ -24,7 +24,7 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class JavadocTagContinuationIndentationCheckExamplesTest
+final class JavadocTagContinuationIndentationCheckExamplesTest
     extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
@@ -32,21 +32,21 @@ public class JavadocTagContinuationIndentationCheckExamplesTest
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocTypeCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocTypeCheckExamplesTest.java
@@ -24,63 +24,63 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class JavadocTypeCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class JavadocTypeCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/javadoc/javadoctype";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example7.txt"), expected);
   }
 
   @Test
-  public void testExample8() throws Exception {
+  void example8() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example8.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocVariableCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/JavadocVariableCheckExamplesTest.java
@@ -24,35 +24,35 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class JavadocVariableCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class JavadocVariableCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/javadoc/javadocvariable";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/MissingJavadocMethodCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/MissingJavadocMethodCheckExamplesTest.java
@@ -24,49 +24,49 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class MissingJavadocMethodCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class MissingJavadocMethodCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/javadoc/missingjavadocmethod";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/MissingJavadocPackageCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/MissingJavadocPackageCheckExamplesTest.java
@@ -24,14 +24,14 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class MissingJavadocPackageCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class MissingJavadocPackageCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/javadoc/missingjavadocpackage";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/MissingJavadocTypeCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/MissingJavadocTypeCheckExamplesTest.java
@@ -24,42 +24,42 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class MissingJavadocTypeCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class MissingJavadocTypeCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/javadoc/missingjavadoctype";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/NonEmptyAtclauseDescriptionCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/NonEmptyAtclauseDescriptionCheckExamplesTest.java
@@ -24,22 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class NonEmptyAtclauseDescriptionCheckExamplesTest
-    extends AbstractExamplesModuleTestSupport {
+final class NonEmptyAtclauseDescriptionCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/javadoc" + "/nonemptyatclausedescription";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/RequireEmptyLineBeforeBlockTagGroupCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/RequireEmptyLineBeforeBlockTagGroupCheckExamplesTest.java
@@ -24,7 +24,7 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class RequireEmptyLineBeforeBlockTagGroupCheckExamplesTest
+final class RequireEmptyLineBeforeBlockTagGroupCheckExamplesTest
     extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
@@ -32,7 +32,7 @@ public class RequireEmptyLineBeforeBlockTagGroupCheckExamplesTest
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/SingleLineJavadocCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/SingleLineJavadocCheckExamplesTest.java
@@ -24,35 +24,35 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class SingleLineJavadocCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class SingleLineJavadocCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/javadoc/singlelinejavadoc";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/SummaryJavadocCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/SummaryJavadocCheckExamplesTest.java
@@ -24,49 +24,49 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class SummaryJavadocCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class SummaryJavadocCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/javadoc/summaryjavadoc";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/WriteTagCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/javadoc/WriteTagCheckExamplesTest.java
@@ -24,35 +24,35 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class WriteTagCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class WriteTagCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/javadoc/writetag";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/metrics/BooleanExpressionComplexityCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/metrics/BooleanExpressionComplexityCheckExamplesTest.java
@@ -24,29 +24,28 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class BooleanExpressionComplexityCheckExamplesTest
-    extends AbstractExamplesModuleTestSupport {
+final class BooleanExpressionComplexityCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/metrics/booleanexpressioncomplexity";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/metrics/ClassDataAbstractionCouplingCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/metrics/ClassDataAbstractionCouplingCheckExamplesTest.java
@@ -24,7 +24,7 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class ClassDataAbstractionCouplingCheckExamplesTest
+final class ClassDataAbstractionCouplingCheckExamplesTest
     extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
@@ -32,77 +32,77 @@ public class ClassDataAbstractionCouplingCheckExamplesTest
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example7.txt"), expected);
   }
 
   @Test
-  public void testExample8() throws Exception {
+  void example8() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example8.txt"), expected);
   }
 
   @Test
-  public void testExample9() throws Exception {
+  void example9() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example9.txt"), expected);
   }
 
   @Test
-  public void testExample10() throws Exception {
+  void example10() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example10.txt"), expected);
   }
 
   @Test
-  public void testExample11() throws Exception {
+  void example11() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example11.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/metrics/ClassFanOutComplexityCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/metrics/ClassFanOutComplexityCheckExamplesTest.java
@@ -24,84 +24,84 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class ClassFanOutComplexityCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class ClassFanOutComplexityCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/metrics/classfanoutcomplexity";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example7.txt"), expected);
   }
 
   @Test
-  public void testExample8() throws Exception {
+  void example8() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example8.txt"), expected);
   }
 
   @Test
-  public void testExample9() throws Exception {
+  void example9() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example9.txt"), expected);
   }
 
   @Test
-  public void testExample10() throws Exception {
+  void example10() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example10.txt"), expected);
   }
 
   @Test
-  public void testExample11() throws Exception {
+  void example11() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example11.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/metrics/CyclomaticComplexityCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/metrics/CyclomaticComplexityCheckExamplesTest.java
@@ -24,28 +24,28 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class CyclomaticComplexityCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class CyclomaticComplexityCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/metrics/cyclomaticcomplexity";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/metrics/JavaNCSSCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/metrics/JavaNCSSCheckExamplesTest.java
@@ -25,35 +25,35 @@ import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
 // -@cs[AbbreviationAsWordInName] Test should be named as its main class.
-public class JavaNCSSCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class JavaNCSSCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/metrics/javancss";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/metrics/NPathComplexityCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/metrics/NPathComplexityCheckExamplesTest.java
@@ -25,21 +25,21 @@ import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
 // -@cs[AbbreviationAsWordInName] Test should be named as its main class.
-public class NPathComplexityCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class NPathComplexityCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/metrics/npathcomplexity";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/modifier/ClassMemberImpliedModifierCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/modifier/ClassMemberImpliedModifierCheckExamplesTest.java
@@ -24,14 +24,14 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class ClassMemberImpliedModifierCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class ClassMemberImpliedModifierCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/modifier/classmemberimpliedmodifier";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/modifier/InterfaceMemberImpliedModifierCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/modifier/InterfaceMemberImpliedModifierCheckExamplesTest.java
@@ -24,7 +24,7 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class InterfaceMemberImpliedModifierCheckExamplesTest
+final class InterfaceMemberImpliedModifierCheckExamplesTest
     extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
@@ -32,14 +32,14 @@ public class InterfaceMemberImpliedModifierCheckExamplesTest
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/modifier/ModifierOrderCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/modifier/ModifierOrderCheckExamplesTest.java
@@ -24,14 +24,14 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class ModifierOrderCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class ModifierOrderCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/modifier/modifierorder";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/modifier/RedundantModifierCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/modifier/RedundantModifierCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class RedundantModifierCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class RedundantModifierCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/modifier/redundantmodifier";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/AbbreviationAsWordInNameExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/AbbreviationAsWordInNameExamplesTest.java
@@ -25,7 +25,7 @@ import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class AbbreviationAsWordInNameExamplesTest extends AbstractExamplesModuleTestSupport {
+final class AbbreviationAsWordInNameExamplesTest extends AbstractExamplesModuleTestSupport {
   private static final int DEFAULT_EXPECTED_CAPITAL_COUNT = 4;
 
   @Override
@@ -34,7 +34,7 @@ public class AbbreviationAsWordInNameExamplesTest extends AbstractExamplesModule
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "18:7: " + getCheckMessage(MSG_KEY, "CURRENT_COUNTER", DEFAULT_EXPECTED_CAPITAL_COUNT),
       "27:8: " + getCheckMessage(MSG_KEY, "incrementCOUNTER", DEFAULT_EXPECTED_CAPITAL_COUNT),
@@ -45,7 +45,7 @@ public class AbbreviationAsWordInNameExamplesTest extends AbstractExamplesModule
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "21:7: " + getCheckMessage(MSG_KEY, "CURRENT_COUNTER", DEFAULT_EXPECTED_CAPITAL_COUNT),
       "23:14: " + getCheckMessage(MSG_KEY, "GLOBAL_COUNTER", DEFAULT_EXPECTED_CAPITAL_COUNT),
@@ -58,7 +58,7 @@ public class AbbreviationAsWordInNameExamplesTest extends AbstractExamplesModule
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final int expectedCapitalCount = 1;
 
     final String[] expected = {
@@ -70,7 +70,7 @@ public class AbbreviationAsWordInNameExamplesTest extends AbstractExamplesModule
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final int expectedCapitalCount = 2;
 
     final String[] expected = {
@@ -83,7 +83,7 @@ public class AbbreviationAsWordInNameExamplesTest extends AbstractExamplesModule
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final int expectedCapitalCount = 1;
 
     final String[] expected = {
@@ -96,7 +96,7 @@ public class AbbreviationAsWordInNameExamplesTest extends AbstractExamplesModule
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final int expectedCapitalCount = 1;
 
     final String[] expected = {
@@ -109,7 +109,7 @@ public class AbbreviationAsWordInNameExamplesTest extends AbstractExamplesModule
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("Example7.java"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/AbstractClassNameCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/AbstractClassNameCheckExamplesTest.java
@@ -25,7 +25,7 @@ import static com.puppycrawl.tools.checkstyle.checks.naming.AbstractClassNameChe
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class AbstractClassNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class AbstractClassNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   private static final String DEFAULT_PATTERN = "^Abstract.+$";
 
   @Override
@@ -34,7 +34,7 @@ public class AbstractClassNameCheckExamplesTest extends AbstractExamplesModuleTe
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "16:3: " + getCheckMessage(MSG_ILLEGAL_ABSTRACT_CLASS_NAME, "Second", DEFAULT_PATTERN),
       "17:3: " + getCheckMessage(MSG_NO_ABSTRACT_CLASS_MODIFIER, "AbstractThird", DEFAULT_PATTERN),
@@ -46,7 +46,7 @@ public class AbstractClassNameCheckExamplesTest extends AbstractExamplesModuleTe
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "18:3: " + getCheckMessage(MSG_ILLEGAL_ABSTRACT_CLASS_NAME, "Second", DEFAULT_PATTERN),
       "21:3: "
@@ -57,7 +57,7 @@ public class AbstractClassNameCheckExamplesTest extends AbstractExamplesModuleTe
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "19:3: " + getCheckMessage(MSG_NO_ABSTRACT_CLASS_MODIFIER, "AbstractThird", DEFAULT_PATTERN),
     };
@@ -66,7 +66,7 @@ public class AbstractClassNameCheckExamplesTest extends AbstractExamplesModuleTe
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String pattern = "^Generator.+$";
 
     final String[] expected = {
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/CatchParameterNameCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/CatchParameterNameCheckExamplesTest.java
@@ -24,7 +24,7 @@ import static com.puppycrawl.tools.checkstyle.checks.naming.CatchParameterNameCh
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class CatchParameterNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class CatchParameterNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
 
   private static final String CATCH_PARAM_NAME_PATTERN_1 = "^(e|t|ex|[a-z][a-z][a-zA-Z]+)$";
   private static final String CATCH_PARAM_NAME_PATTERN_2 = "^[a-z][a-zA-Z0-9]+$";
@@ -35,7 +35,7 @@ public class CatchParameterNameCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "18:40: " + getCheckMessage(MSG_INVALID_PATTERN, "e123", CATCH_PARAM_NAME_PATTERN_1),
       "20:35: " + getCheckMessage(MSG_INVALID_PATTERN, "ab", CATCH_PARAM_NAME_PATTERN_1),
@@ -48,7 +48,7 @@ public class CatchParameterNameCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "18:34: " + getCheckMessage(MSG_INVALID_PATTERN, "e", CATCH_PARAM_NAME_PATTERN_2),
       "26:24: "
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/ClassTypeParameterNameCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/ClassTypeParameterNameCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.naming.AbstractClassNameChe
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class ClassTypeParameterNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class ClassTypeParameterNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/naming/classtypeparametername";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String pattern = "^[A-Z]$";
     final String[] expected = {
       "14:18: " + getCheckMessage(MSG_ILLEGAL_ABSTRACT_CLASS_NAME, "t", pattern),
@@ -44,7 +44,7 @@ public class ClassTypeParameterNameCheckExamplesTest extends AbstractExamplesMod
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String pattern = "^[A-Z]{2,}$";
     final String[] expected = {
       "15:18: " + getCheckMessage(MSG_ILLEGAL_ABSTRACT_CLASS_NAME, "T", pattern),
@@ -57,7 +57,7 @@ public class ClassTypeParameterNameCheckExamplesTest extends AbstractExamplesMod
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String pattern = "(^[A-Z][0-9]?)$|([A-Z][a-zA-Z0-9]*[T]$)";
     final String[] expected = {
       "16:18: " + getCheckMessage(MSG_ILLEGAL_ABSTRACT_CLASS_NAME, "t", pattern),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/ConstantNameCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/ConstantNameCheckExamplesTest.java
@@ -24,7 +24,7 @@ import static com.puppycrawl.tools.checkstyle.checks.naming.ConstantNameCheck.MS
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class ConstantNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class ConstantNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   private static final String DEFAULT_PATTERN = "^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$";
 
   @Override
@@ -33,7 +33,7 @@ public class ConstantNameCheckExamplesTest extends AbstractExamplesModuleTestSup
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "17:20: " + getCheckMessage(MSG_INVALID_PATTERN, "third_Constant3", DEFAULT_PATTERN),
       "18:28: " + getCheckMessage(MSG_INVALID_PATTERN, "fourth_Const4", DEFAULT_PATTERN),
@@ -47,7 +47,7 @@ public class ConstantNameCheckExamplesTest extends AbstractExamplesModuleTestSup
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String pattern = "^log(ger)?$|^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$";
 
     final String[] expected = {
@@ -61,7 +61,7 @@ public class ConstantNameCheckExamplesTest extends AbstractExamplesModuleTestSup
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "20:20: " + getCheckMessage(MSG_INVALID_PATTERN, "third_Constant3", DEFAULT_PATTERN),
       "21:28: " + getCheckMessage(MSG_INVALID_PATTERN, "fourth_Const4", DEFAULT_PATTERN),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/IllegalIdentifierNameCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/IllegalIdentifierNameCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class IllegalIdentifierNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class IllegalIdentifierNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/naming/illegalidentifiername";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/InterfaceTypeParameterNameCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/InterfaceTypeParameterNameCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.naming.AbstractNameCheck.MS
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class InterfaceTypeParameterNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class InterfaceTypeParameterNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/naming/interfacetypeparametername";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
 
     final String[] expected = {
       "14:29: " + getCheckMessage(MSG_INVALID_PATTERN, "t", "^[A-Z]$"),
@@ -41,7 +41,7 @@ public class InterfaceTypeParameterNameCheckExamplesTest extends AbstractExample
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "17:28: " + getCheckMessage(MSG_INVALID_PATTERN, "type", "^[a-zA-Z]$"),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/LambdaParameterNameCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/LambdaParameterNameCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.naming.AbstractNameCheck.MS
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class LambdaParameterNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class LambdaParameterNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/naming/lambdaparametername";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "17:11: " + getCheckMessage(MSG_INVALID_PATTERN, "S", "^[a-z][a-zA-Z0-9]*$"),
     };
@@ -40,7 +40,7 @@ public class LambdaParameterNameCheckExamplesTest extends AbstractExamplesModule
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "20:40: " + getCheckMessage(MSG_INVALID_PATTERN, "_s", "^[a-z]([a-zA-Z]+)*$"),
       "25:23: " + getCheckMessage(MSG_INVALID_PATTERN, "Word", "^[a-z]([a-zA-Z]+)*$"),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/LocalFinalVariableNameCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/LocalFinalVariableNameCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.naming.AbstractNameCheck.MS
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class LocalFinalVariableNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class LocalFinalVariableNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/naming/localfinalvariablename";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "17:17: " + getCheckMessage(MSG_INVALID_PATTERN, "VAR1", "^[a-z][a-zA-Z0-9]*$"),
       "20:17: " + getCheckMessage(MSG_INVALID_PATTERN, "VAR2", "^[a-z][a-zA-Z0-9]*$"),
@@ -41,7 +41,7 @@ public class LocalFinalVariableNameCheckExamplesTest extends AbstractExamplesMod
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "18:17: " + getCheckMessage(MSG_INVALID_PATTERN, "var1", "^[A-Z][A-Z0-9]*$"),
       "21:17: " + getCheckMessage(MSG_INVALID_PATTERN, "var2", "^[A-Z][A-Z0-9]*$"),
@@ -51,7 +51,7 @@ public class LocalFinalVariableNameCheckExamplesTest extends AbstractExamplesMod
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "19:17: " + getCheckMessage(MSG_INVALID_PATTERN, "scanner", "^[A-Z][A-Z0-9]*$"),
       "23:30: " + getCheckMessage(MSG_INVALID_PATTERN, "ex", "^[A-Z][A-Z0-9]*$"),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/LocalVariableNameCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/LocalVariableNameCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.naming.AbstractNameCheck.MS
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class LocalVariableNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class LocalVariableNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/naming/localvariablename";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String pattern = "^[a-z][a-zA-Z0-9]*$";
     final String[] expected = {
       "15:14: " + getCheckMessage(MSG_INVALID_PATTERN, "VAR", pattern),
@@ -42,7 +42,7 @@ public class LocalVariableNameCheckExamplesTest extends AbstractExamplesModuleTe
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String pattern = "^[a-z](_?[a-zA-Z0-9]+)*$";
     final String[] expected = {
       "17:14: " + getCheckMessage(MSG_INVALID_PATTERN, "VAR", pattern),
@@ -52,7 +52,7 @@ public class LocalVariableNameCheckExamplesTest extends AbstractExamplesModuleTe
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String pattern = "^[a-z](_?[a-zA-Z0-9]+)*$";
     final String[] expected = {
       "20:13: " + getCheckMessage(MSG_INVALID_PATTERN, "K", pattern),
@@ -63,7 +63,7 @@ public class LocalVariableNameCheckExamplesTest extends AbstractExamplesModuleTe
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String pattern = "^[a-z][_a-zA-Z0-9]+$";
     final String[] expected = {
       "21:9: " + getCheckMessage(MSG_INVALID_PATTERN, "g", pattern),
@@ -77,7 +77,7 @@ public class LocalVariableNameCheckExamplesTest extends AbstractExamplesModuleTe
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String pattern = "^[a-z][_a-zA-Z0-9]{2,}$";
     final String[] expected = {
       "17:9: " + getCheckMessage(MSG_INVALID_PATTERN, "i", pattern),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/MemberNameCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/MemberNameCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.naming.MemberNameCheck.MSG_
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class MemberNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class MemberNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/naming/membername";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "21:14: " + getCheckMessage(MSG_INVALID_PATTERN, "NUM1", "^[a-z][a-zA-Z0-9]*$"),
       "23:17: " + getCheckMessage(MSG_INVALID_PATTERN, "NUM2", "^[a-z][a-zA-Z0-9]*$"),
@@ -43,7 +43,7 @@ public class MemberNameCheckExamplesTest extends AbstractExamplesModuleTestSuppo
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "16:14: " + getCheckMessage(MSG_INVALID_PATTERN, "num1", "^m[A-Z][a-zA-Z0-9]*$"),
       "20:15: " + getCheckMessage(MSG_INVALID_PATTERN, "num4", "^m[A-Z][a-zA-Z0-9]*$"),
@@ -53,7 +53,7 @@ public class MemberNameCheckExamplesTest extends AbstractExamplesModuleTestSuppo
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "16:17: " + getCheckMessage(MSG_INVALID_PATTERN, "NUM2", "^[a-z][a-zA-Z0-9]*$"),
       "18:7: " + getCheckMessage(MSG_INVALID_PATTERN, "NUM3", "^[a-z][a-zA-Z0-9]*$"),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/MethodNameCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/MethodNameCheckExamplesTest.java
@@ -25,14 +25,14 @@ import static com.puppycrawl.tools.checkstyle.checks.naming.MethodNameCheck.MSG_
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class MethodNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class MethodNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/naming/methodname";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "15:16: " + getCheckMessage(MSG_INVALID_PATTERN, "Method3", "^[a-z][a-zA-Z0-9]*$"),
       "16:15: " + getCheckMessage(MSG_INVALID_PATTERN, "Method4", "^[a-z][a-zA-Z0-9]*$"),
@@ -42,7 +42,7 @@ public class MethodNameCheckExamplesTest extends AbstractExamplesModuleTestSuppo
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "16:15: " + getCheckMessage(MSG_INVALID_PATTERN, "Method2", "^[a-z](_?[a-zA-Z0-9]+)*$"),
     };
@@ -51,14 +51,14 @@ public class MethodNameCheckExamplesTest extends AbstractExamplesModuleTestSuppo
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.java"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {
       "17:15: " + getCheckMessage(MSG_KEY, "Example4"),
     };
@@ -67,7 +67,7 @@ public class MethodNameCheckExamplesTest extends AbstractExamplesModuleTestSuppo
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {
       "19:16: " + getCheckMessage(MSG_INVALID_PATTERN, "Method3", "^[a-z](_?[a-zA-Z0-9]+)*$"),
       "20:8: " + getCheckMessage(MSG_INVALID_PATTERN, "Method4", "^[a-z](_?[a-zA-Z0-9]+)*$"),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/MethodTypeParameterNameCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/MethodTypeParameterNameCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.naming.AbstractNameCheck.MS
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class MethodTypeParameterNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class MethodTypeParameterNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/naming/methodtypeparametername";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "14:11: " + getCheckMessage(MSG_INVALID_PATTERN, "a", "^[A-Z]$"),
       "16:11: " + getCheckMessage(MSG_INVALID_PATTERN, "k", "^[A-Z]$"),
@@ -41,7 +41,7 @@ public class MethodTypeParameterNameCheckExamplesTest extends AbstractExamplesMo
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.java"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/PackageNameCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/PackageNameCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class PackageNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class PackageNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/naming/packagename";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/ParameterNameCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/ParameterNameCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.naming.ParameterNameCheck.M
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class ParameterNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class ParameterNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/naming/parametername";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "14:20: " + getCheckMessage(MSG_INVALID_PATTERN, "V2", "^[a-z][a-zA-Z0-9]*$"),
     };
@@ -40,7 +40,7 @@ public class ParameterNameCheckExamplesTest extends AbstractExamplesModuleTestSu
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "17:20: " + getCheckMessage(MSG_INVALID_PATTERN, "V3", "^[a-z][_a-zA-Z0-9]+$"),
     };
@@ -49,7 +49,7 @@ public class ParameterNameCheckExamplesTest extends AbstractExamplesModuleTestSu
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "16:20: " + getCheckMessage(MSG_INVALID_PATTERN, "V2", "^[a-z][a-zA-Z0-9]*$"),
     };
@@ -58,7 +58,7 @@ public class ParameterNameCheckExamplesTest extends AbstractExamplesModuleTestSu
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {
       "16:20: " + getCheckMessage(MSG_INVALID_PATTERN, "v_2", "^[a-z][a-zA-Z0-9]+$"),
       "17:20: " + getCheckMessage(MSG_INVALID_PATTERN, "V3", "^[a-z][a-zA-Z0-9]+$"),
@@ -68,7 +68,7 @@ public class ParameterNameCheckExamplesTest extends AbstractExamplesModuleTestSu
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {
       "25:26: " + "Parameter name 'V2' must match pattern '^[a-z]([a-z0-9][a-zA-Z0-9]*)?$'",
       "27:23: " + "Parameter name 'b' must match pattern '^[a-z][a-z0-9][a-zA-Z0-9]*$'",
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/PatternVariableNameCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/PatternVariableNameCheckExamplesTest.java
@@ -24,28 +24,28 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class PatternVariableNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class PatternVariableNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/naming/patternvariablename";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/RecordComponentNameCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/RecordComponentNameCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class RecordComponentNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class RecordComponentNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/naming/recordcomponentname";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/RecordTypeParameterNameCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/RecordTypeParameterNameCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class RecordTypeParameterNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class RecordTypeParameterNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/naming/recordtypeparametername";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/StaticVariableNameCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/StaticVariableNameCheckExamplesTest.java
@@ -24,7 +24,7 @@ import static com.puppycrawl.tools.checkstyle.checks.naming.AbstractNameCheck.MS
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class StaticVariableNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class StaticVariableNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
 
   public static final String STATIC_VAR_NAME_PATTERN_1 = "^[a-z][a-zA-Z0-9]*$";
   public static final String STATIC_VAR_NAME_PATTERN_2 = "^[a-z](_?[a-zA-Z0-9]+)*$";
@@ -35,7 +35,7 @@ public class StaticVariableNameCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "19:21: " + getCheckMessage(MSG_INVALID_PATTERN, "ItStatic1", STATIC_VAR_NAME_PATTERN_1),
       "20:24: " + getCheckMessage(MSG_INVALID_PATTERN, "ItStatic2", STATIC_VAR_NAME_PATTERN_1),
@@ -50,7 +50,7 @@ public class StaticVariableNameCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "21:22: " + getCheckMessage(MSG_INVALID_PATTERN, "ItStatic", STATIC_VAR_NAME_PATTERN_1),
       "24:22: " + getCheckMessage(MSG_INVALID_PATTERN, "It_Static1", STATIC_VAR_NAME_PATTERN_1),
@@ -61,7 +61,7 @@ public class StaticVariableNameCheckExamplesTest extends AbstractExamplesModuleT
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "19:21: " + getCheckMessage(MSG_INVALID_PATTERN, "ItStatic1", STATIC_VAR_NAME_PATTERN_2),
       "20:24: " + getCheckMessage(MSG_INVALID_PATTERN, "ItStatic2", STATIC_VAR_NAME_PATTERN_2),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/TypeNameCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/naming/TypeNameCheckExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.naming.AbstractNameCheck.MS
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class TypeNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class TypeNameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/naming/typename";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "15:8: " + getCheckMessage(MSG_INVALID_PATTERN, "Third_Name", "^[A-Z][a-zA-Z0-9]*$"),
       "16:17: " + getCheckMessage(MSG_INVALID_PATTERN, "FourthName_", "^[A-Z][a-zA-Z0-9]*$"),
@@ -41,7 +41,7 @@ public class TypeNameCheckExamplesTest extends AbstractExamplesModuleTestSupport
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "16:7: " + getCheckMessage(MSG_INVALID_PATTERN, "Example2", "^[a-z](_?[a-zA-Z0-9]+)*$"),
       "18:16: " + getCheckMessage(MSG_INVALID_PATTERN, "SecondName", "^[a-z](_?[a-zA-Z0-9]+)*$"),
@@ -51,7 +51,7 @@ public class TypeNameCheckExamplesTest extends AbstractExamplesModuleTestSupport
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "19:13: " + getCheckMessage(MSG_INVALID_PATTERN, "SecondName", "^I_[a-zA-Z0-9]*$"),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpCheckExamplesTest.java
@@ -24,98 +24,98 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class RegexpCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class RegexpCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/regexp/regexp";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example7.txt"), expected);
   }
 
   @Test
-  public void testExample8() throws Exception {
+  void example8() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example8.txt"), expected);
   }
 
   @Test
-  public void testExample9() throws Exception {
+  void example9() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example9.txt"), expected);
   }
 
   @Test
-  public void testExample10() throws Exception {
+  void example10() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example10.txt"), expected);
   }
 
   @Test
-  public void testExample11() throws Exception {
+  void example11() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example11.txt"), expected);
   }
 
   @Test
-  public void testExample12() throws Exception {
+  void example12() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example12.txt"), expected);
   }
 
   @Test
-  public void testExample13() throws Exception {
+  void example13() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example13.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpMultilineCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpMultilineCheckExamplesTest.java
@@ -24,56 +24,56 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class RegexpMultilineCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class RegexpMultilineCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/regexp/regexpmultiline";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example7.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpOnFilenameCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpOnFilenameCheckExamplesTest.java
@@ -24,56 +24,56 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class RegexpOnFilenameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class RegexpOnFilenameCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/regexp/regexponfilename";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example7.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpSinglelineCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpSinglelineCheckExamplesTest.java
@@ -24,56 +24,56 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class RegexpSinglelineCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class RegexpSinglelineCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/regexp/regexpsingleline";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example7.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpSinglelineJavaCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/regexp/RegexpSinglelineJavaCheckExamplesTest.java
@@ -24,56 +24,56 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class RegexpSinglelineJavaCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class RegexpSinglelineJavaCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/regexp/regexpsinglelinejava";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example7.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/sizes/AnonInnerLengthCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/sizes/AnonInnerLengthCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class AnonInnerLengthCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class AnonInnerLengthCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/sizes/anoninnerlength";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/sizes/ExecutableStatementCountCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/sizes/ExecutableStatementCountCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class ExecutableStatementCountCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class ExecutableStatementCountCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/sizes/executablestatementcount";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/sizes/FileLengthCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/sizes/FileLengthCheckExamplesTest.java
@@ -24,21 +24,21 @@ import static com.puppycrawl.tools.checkstyle.checks.sizes.FileLengthCheck.MSG_K
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class FileLengthCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class FileLengthCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/sizes/filelength";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.java"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "1: " + getCheckMessage(MSG_KEY, 18, 5),
     };
@@ -47,7 +47,7 @@ public class FileLengthCheckExamplesTest extends AbstractExamplesModuleTestSuppo
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.java"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/sizes/LambdaBodyLengthExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/sizes/LambdaBodyLengthExamplesTest.java
@@ -24,7 +24,7 @@ import static com.puppycrawl.tools.checkstyle.checks.sizes.LambdaBodyLengthCheck
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class LambdaBodyLengthExamplesTest extends AbstractExamplesModuleTestSupport {
+final class LambdaBodyLengthExamplesTest extends AbstractExamplesModuleTestSupport {
   private static final int DEFAULT_MAX = 10;
 
   @Override
@@ -33,7 +33,7 @@ public class LambdaBodyLengthExamplesTest extends AbstractExamplesModuleTestSupp
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "25:20: " + getCheckMessage(MSG_KEY, 11, DEFAULT_MAX),
       "36:20: " + getCheckMessage(MSG_KEY, 11, DEFAULT_MAX),
@@ -43,7 +43,7 @@ public class LambdaBodyLengthExamplesTest extends AbstractExamplesModuleTestSupp
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final int max = 5;
 
     final String[] expected = {
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/sizes/LineLengthCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/sizes/LineLengthCheckExamplesTest.java
@@ -24,49 +24,49 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class LineLengthCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class LineLengthCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/sizes/linelength";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/sizes/MethodCountCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/sizes/MethodCountCheckExamplesTest.java
@@ -24,28 +24,28 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class MethodCountCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class MethodCountCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/sizes/methodcount";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/sizes/MethodLengthCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/sizes/MethodLengthCheckExamplesTest.java
@@ -24,28 +24,28 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class MethodLengthCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class MethodLengthCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/sizes/methodlength";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/sizes/OuterTypeNumberCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/sizes/OuterTypeNumberCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class OuterTypeNumberCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class OuterTypeNumberCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/sizes/outertypenumber";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/sizes/ParameterNumberCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/sizes/ParameterNumberCheckExamplesTest.java
@@ -24,28 +24,28 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class ParameterNumberCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class ParameterNumberCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/sizes/parameternumber";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/sizes/RecordComponentNumberCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/sizes/RecordComponentNumberCheckExamplesTest.java
@@ -24,28 +24,28 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class RecordComponentNumberCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class RecordComponentNumberCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/sizes/recordcomponentnumber";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/EmptyForInitializerPadExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/EmptyForInitializerPadExamplesTest.java
@@ -25,14 +25,14 @@ import static com.puppycrawl.tools.checkstyle.checks.whitespace.EmptyForInitiali
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class EmptyForInitializerPadExamplesTest extends AbstractExamplesModuleTestSupport {
+final class EmptyForInitializerPadExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/whitespace/emptyforinitializerpad";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "17:11: " + getCheckMessage(MSG_PRECEDED, ";"),
       "20:11: " + getCheckMessage(MSG_PRECEDED, ";"),
@@ -42,7 +42,7 @@ public class EmptyForInitializerPadExamplesTest extends AbstractExamplesModuleTe
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "20:10: " + getCheckMessage(MSG_NOT_PRECEDED, ";"),
       "21:10: " + getCheckMessage(MSG_NOT_PRECEDED, ";"),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/EmptyForIteratorPadExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/EmptyForIteratorPadExamplesTest.java
@@ -25,14 +25,14 @@ import static com.puppycrawl.tools.checkstyle.checks.whitespace.EmptyForIterator
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class EmptyForIteratorPadExamplesTest extends AbstractExamplesModuleTestSupport {
+final class EmptyForIteratorPadExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/whitespace/emptyforiteratorpad";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "22:66: " + getCheckMessage(MSG_WS_FOLLOWED, ";"),
     };
@@ -41,7 +41,7 @@ public class EmptyForIteratorPadExamplesTest extends AbstractExamplesModuleTestS
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "23:65: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, ";"),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/EmptyLineSeparatorExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/EmptyLineSeparatorExamplesTest.java
@@ -26,14 +26,14 @@ import static com.puppycrawl.tools.checkstyle.checks.whitespace.EmptyLineSeparat
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class EmptyLineSeparatorExamplesTest extends AbstractExamplesModuleTestSupport {
+final class EmptyLineSeparatorExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/whitespace/emptylineseparator";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "14:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "package"),
       "15:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "import"),
@@ -45,7 +45,7 @@ public class EmptyLineSeparatorExamplesTest extends AbstractExamplesModuleTestSu
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "22:3: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "VARIABLE_DEF"),
       "29:3: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "METHOD_DEF"),
@@ -55,7 +55,7 @@ public class EmptyLineSeparatorExamplesTest extends AbstractExamplesModuleTestSu
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "16:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "package"),
       "17:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "import"),
@@ -66,7 +66,7 @@ public class EmptyLineSeparatorExamplesTest extends AbstractExamplesModuleTestSu
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {
       "16:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "package"),
       "17:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "import"),
@@ -80,7 +80,7 @@ public class EmptyLineSeparatorExamplesTest extends AbstractExamplesModuleTestSu
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {
       "17:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "package"),
       "18:1: " + getCheckMessage(MSG_SHOULD_BE_SEPARATED, "import"),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/FileTabCharacterExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/FileTabCharacterExamplesTest.java
@@ -26,14 +26,14 @@ import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
 import org.junit.jupiter.api.Test;
 
-public class FileTabCharacterExamplesTest extends AbstractExamplesModuleTestSupport {
+final class FileTabCharacterExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/whitespace/filetabcharacter";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "13:1: " + getCheckMessage(MSG_FILE_CONTAINS_TAB),
     };
@@ -42,7 +42,7 @@ public class FileTabCharacterExamplesTest extends AbstractExamplesModuleTestSupp
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "15:1: " + getCheckMessage(MSG_CONTAINS_TAB), "17:1: " + getCheckMessage(MSG_CONTAINS_TAB),
     };
@@ -51,7 +51,7 @@ public class FileTabCharacterExamplesTest extends AbstractExamplesModuleTestSupp
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "15:1: " + getCheckMessage(MSG_FILE_CONTAINS_TAB),
     };
@@ -60,7 +60,7 @@ public class FileTabCharacterExamplesTest extends AbstractExamplesModuleTestSupp
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {
       "13:1: " + getCheckMessage(MSG_FILE_CONTAINS_TAB),
     };
@@ -69,7 +69,7 @@ public class FileTabCharacterExamplesTest extends AbstractExamplesModuleTestSupp
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
 
     verifyWithInlineConfigParser(getPath("Example5.html"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/GenericWhitespaceCheckExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/GenericWhitespaceCheckExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class GenericWhitespaceCheckExamplesTest extends AbstractExamplesModuleTestSupport {
+final class GenericWhitespaceCheckExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/whitespace/genericwhitespace";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/MethodParamPadExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/MethodParamPadExamplesTest.java
@@ -26,14 +26,14 @@ import static com.puppycrawl.tools.checkstyle.checks.whitespace.MethodParamPadCh
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class MethodParamPadExamplesTest extends AbstractExamplesModuleTestSupport {
+final class MethodParamPadExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/whitespace/methodparampad";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "19:19: " + getCheckMessage(MSG_WS_PRECEDED, "("),
       "20:11: " + getCheckMessage(MSG_WS_PRECEDED, "("),
@@ -44,7 +44,7 @@ public class MethodParamPadExamplesTest extends AbstractExamplesModuleTestSuppor
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "27:21: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "("),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/NoLineWrapExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/NoLineWrapExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.whitespace.NoLineWrapCheck.
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class NoLineWrapExamplesTest extends AbstractExamplesModuleTestSupport {
+final class NoLineWrapExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/whitespace/nolinewrap";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "12:1: " + getCheckMessage(MSG_KEY, "package"),
       "15:1: " + getCheckMessage(MSG_KEY, "import"),
@@ -42,7 +42,7 @@ public class NoLineWrapExamplesTest extends AbstractExamplesModuleTestSupport {
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "12:1: " + getCheckMessage(MSG_KEY, "package"),
       "16:1: " + getCheckMessage(MSG_KEY, "import"),
@@ -53,7 +53,7 @@ public class NoLineWrapExamplesTest extends AbstractExamplesModuleTestSupport {
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "14:1: " + getCheckMessage(MSG_KEY, "import"),
     };
@@ -62,7 +62,7 @@ public class NoLineWrapExamplesTest extends AbstractExamplesModuleTestSupport {
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {
       "18:1: " + getCheckMessage(MSG_KEY, "import"),
     };
@@ -71,7 +71,7 @@ public class NoLineWrapExamplesTest extends AbstractExamplesModuleTestSupport {
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {
       "19:1: " + getCheckMessage(MSG_KEY, "CLASS_DEF"),
       "25:3: " + getCheckMessage(MSG_KEY, "METHOD_DEF"),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/NoWhitespaceAfterExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/NoWhitespaceAfterExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.whitespace.NoWhitespaceAfte
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class NoWhitespaceAfterExamplesTest extends AbstractExamplesModuleTestSupport {
+final class NoWhitespaceAfterExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/whitespace/nowhitespaceafter";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "23:12: " + getCheckMessage(MSG_KEY, "."),
       "28:9: " + getCheckMessage(MSG_KEY, "int"),
@@ -42,7 +42,7 @@ public class NoWhitespaceAfterExamplesTest extends AbstractExamplesModuleTestSup
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "19:12: " + getCheckMessage(MSG_KEY, "."), "26:12: " + getCheckMessage(MSG_KEY, "."),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/NoWhitespaceBeforeCaseDefaultColonExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/NoWhitespaceBeforeCaseDefaultColonExamplesTest.java
@@ -24,7 +24,7 @@ import static com.puppycrawl.tools.checkstyle.checks.whitespace.NoWhitespaceBefo
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class NoWhitespaceBeforeCaseDefaultColonExamplesTest
+final class NoWhitespaceBeforeCaseDefaultColonExamplesTest
     extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
@@ -33,7 +33,7 @@ public class NoWhitespaceBeforeCaseDefaultColonExamplesTest
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "19:14: " + getCheckMessage(MSG_KEY, ":"),
       "23:15: " + getCheckMessage(MSG_KEY, ":"),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/NoWhitespaceBeforeExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/NoWhitespaceBeforeExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.whitespace.NoWhitespaceBefo
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class NoWhitespaceBeforeExamplesTest extends AbstractExamplesModuleTestSupport {
+final class NoWhitespaceBeforeExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/whitespace/nowhitespacebefore";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "19:9: " + getCheckMessage(MSG_KEY, "++"),
       "21:20: " + getCheckMessage(MSG_KEY, ";"),
@@ -44,7 +44,7 @@ public class NoWhitespaceBeforeExamplesTest extends AbstractExamplesModuleTestSu
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "23:31: " + getCheckMessage(MSG_KEY, "..."),
     };
@@ -53,7 +53,7 @@ public class NoWhitespaceBeforeExamplesTest extends AbstractExamplesModuleTestSu
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "21:10: " + getCheckMessage(MSG_KEY, "."), "23:74: " + getCheckMessage(MSG_KEY, "::"),
     };
@@ -62,7 +62,7 @@ public class NoWhitespaceBeforeExamplesTest extends AbstractExamplesModuleTestSu
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {
       "21:11: " + getCheckMessage(MSG_KEY, "."), "23:40: " + getCheckMessage(MSG_KEY, "::"),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/OperatorWrapExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/OperatorWrapExamplesTest.java
@@ -25,14 +25,14 @@ import static com.puppycrawl.tools.checkstyle.checks.whitespace.OperatorWrapChec
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class OperatorWrapExamplesTest extends AbstractExamplesModuleTestSupport {
+final class OperatorWrapExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/whitespace/operatorwrap";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "16:24: " + getCheckMessage(MSG_LINE_NEW, "+"),
       "19:12: " + getCheckMessage(MSG_LINE_NEW, "=="),
@@ -43,7 +43,7 @@ public class OperatorWrapExamplesTest extends AbstractExamplesModuleTestSupport
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "23:13: " + getCheckMessage(MSG_LINE_PREVIOUS, "="),
       "27:13: " + getCheckMessage(MSG_LINE_PREVIOUS, "+="),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/ParenPadExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/ParenPadExamplesTest.java
@@ -27,14 +27,14 @@ import static com.puppycrawl.tools.checkstyle.checks.whitespace.AbstractParenPad
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class ParenPadExamplesTest extends AbstractExamplesModuleTestSupport {
+final class ParenPadExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/whitespace/parenpad";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "18:8: " + getCheckMessage(MSG_WS_FOLLOWED, "("),
       "21:25: " + getCheckMessage(MSG_WS_PRECEDED, ")"),
@@ -45,7 +45,7 @@ public class ParenPadExamplesTest extends AbstractExamplesModuleTestSupport {
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "29:27: " + getCheckMessage(MSG_WS_NOT_PRECEDED, ")"),
       "39:12: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "("),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/SeparatorWrapExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/SeparatorWrapExamplesTest.java
@@ -25,14 +25,14 @@ import static com.puppycrawl.tools.checkstyle.checks.whitespace.SeparatorWrapChe
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class SeparatorWrapExamplesTest extends AbstractExamplesModuleTestSupport {
+final class SeparatorWrapExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/whitespace/separatorwrap";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "24:21: " + getCheckMessage(MSG_LINE_PREVIOUS, ","),
       "26:11: " + getCheckMessage(MSG_LINE_PREVIOUS, "."),
@@ -42,7 +42,7 @@ public class SeparatorWrapExamplesTest extends AbstractExamplesModuleTestSupport
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "23:36: " + getCheckMessage(MSG_LINE_NEW, "::"),
     };
@@ -51,7 +51,7 @@ public class SeparatorWrapExamplesTest extends AbstractExamplesModuleTestSupport
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "19:8: " + getCheckMessage(MSG_LINE_NEW, ","), "22:17: " + getCheckMessage(MSG_LINE_NEW, ","),
     };
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/SingleSpaceSeparatorExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/SingleSpaceSeparatorExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.whitespace.SingleSpaceSepar
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class SingleSpaceSeparatorExamplesTest extends AbstractExamplesModuleTestSupport {
+final class SingleSpaceSeparatorExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/whitespace/singlespaceseparator";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "15:15: " + getCheckMessage(MSG_KEY),
       "16:13: " + getCheckMessage(MSG_KEY),
@@ -42,7 +42,7 @@ public class SingleSpaceSeparatorExamplesTest extends AbstractExamplesModuleTest
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "18:19: " + getCheckMessage(MSG_KEY),
       "20:28: " + getCheckMessage(MSG_KEY),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/TypecastParenPadExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/TypecastParenPadExamplesTest.java
@@ -27,14 +27,14 @@ import static com.puppycrawl.tools.checkstyle.checks.whitespace.AbstractParenPad
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class TypecastParenPadExamplesTest extends AbstractExamplesModuleTestSupport {
+final class TypecastParenPadExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/whitespace/typecastparenpad";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "17:11: " + getCheckMessage(MSG_WS_FOLLOWED, "("),
       "17:17: " + getCheckMessage(MSG_WS_PRECEDED, ")"),
@@ -46,7 +46,7 @@ public class TypecastParenPadExamplesTest extends AbstractExamplesModuleTestSupp
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "21:11: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "("),
       "25:11: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "("),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/WhitespaceAfterExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/WhitespaceAfterExamplesTest.java
@@ -24,14 +24,14 @@ import static com.puppycrawl.tools.checkstyle.checks.whitespace.WhitespaceAfterC
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class WhitespaceAfterExamplesTest extends AbstractExamplesModuleTestSupport {
+final class WhitespaceAfterExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/whitespace/whitespaceafter";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "19:12: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "if"),
       "23:16: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, ","),
@@ -50,7 +50,7 @@ public class WhitespaceAfterExamplesTest extends AbstractExamplesModuleTestSuppo
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "19:14: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, ";"),
       "22:17: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, ","),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/WhitespaceAroundExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/checks/whitespace/WhitespaceAroundExamplesTest.java
@@ -25,14 +25,14 @@ import static com.puppycrawl.tools.checkstyle.checks.whitespace.WhitespaceAround
 import com.puppycrawl.tools.checkstyle.AbstractExamplesModuleTestSupport;
 import org.junit.jupiter.api.Test;
 
-public class WhitespaceAroundExamplesTest extends AbstractExamplesModuleTestSupport {
+final class WhitespaceAroundExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/checks/whitespace/whitespacearound";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {
       "15:20: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "{"),
       "15:20: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "{"),
@@ -54,7 +54,7 @@ public class WhitespaceAroundExamplesTest extends AbstractExamplesModuleTestSupp
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {
       "21:10: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "="),
       "21:10: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "="),
@@ -78,7 +78,7 @@ public class WhitespaceAroundExamplesTest extends AbstractExamplesModuleTestSupp
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {
       "17:22: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "}"),
     };
@@ -87,7 +87,7 @@ public class WhitespaceAroundExamplesTest extends AbstractExamplesModuleTestSupp
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {
       "18:8: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "="),
       "18:8: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "="),
@@ -97,7 +97,7 @@ public class WhitespaceAroundExamplesTest extends AbstractExamplesModuleTestSupp
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {
       "18:28: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "{"),
       "18:29: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "}"),
@@ -107,7 +107,7 @@ public class WhitespaceAroundExamplesTest extends AbstractExamplesModuleTestSupp
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {
       "20:10: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "="),
       "20:10: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "="),
@@ -117,7 +117,7 @@ public class WhitespaceAroundExamplesTest extends AbstractExamplesModuleTestSupp
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {
       "21:10: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "="),
       "21:10: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "="),
@@ -127,7 +127,7 @@ public class WhitespaceAroundExamplesTest extends AbstractExamplesModuleTestSupp
   }
 
   @Test
-  public void testExample8() throws Exception {
+  void example8() throws Exception {
     final String[] expected = {
       "19:10: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "="),
       "19:10: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "="),
@@ -137,7 +137,7 @@ public class WhitespaceAroundExamplesTest extends AbstractExamplesModuleTestSupp
   }
 
   @Test
-  public void testExample9() throws Exception {
+  void example9() throws Exception {
     final String[] expected = {
       "18:10: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "="),
       "18:10: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "="),
@@ -147,7 +147,7 @@ public class WhitespaceAroundExamplesTest extends AbstractExamplesModuleTestSupp
   }
 
   @Test
-  public void testExample10() throws Exception {
+  void example10() throws Exception {
     final String[] expected = {
       "18:10: " + getCheckMessage(MSG_WS_NOT_PRECEDED, "="),
       "18:10: " + getCheckMessage(MSG_WS_NOT_FOLLOWED, "="),
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/filefilters/BeforeExecutionExclusionFileFilterExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/filefilters/BeforeExecutionExclusionFileFilterExamplesTest.java
@@ -24,7 +24,7 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class BeforeExecutionExclusionFileFilterExamplesTest
+final class BeforeExecutionExclusionFileFilterExamplesTest
     extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
@@ -32,21 +32,21 @@ public class BeforeExecutionExclusionFileFilterExamplesTest
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/filters/SeverityMatchFilterExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/filters/SeverityMatchFilterExamplesTest.java
@@ -24,14 +24,14 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class SeverityMatchFilterExamplesTest extends AbstractExamplesModuleTestSupport {
+final class SeverityMatchFilterExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/filters/severitymatchfilter";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/filters/SuppressWarningsFilterExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/filters/SuppressWarningsFilterExamplesTest.java
@@ -24,21 +24,21 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class SuppressWarningsFilterExamplesTest extends AbstractExamplesModuleTestSupport {
+final class SuppressWarningsFilterExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/filters/suppresswarningsfilter";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/filters/SuppressWithNearbyCommentFilterExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/filters/SuppressWithNearbyCommentFilterExamplesTest.java
@@ -24,63 +24,63 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class SuppressWithNearbyCommentFilterExamplesTest extends AbstractExamplesModuleTestSupport {
+final class SuppressWithNearbyCommentFilterExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/filters/suppresswithnearbycommentfilter";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example7.txt"), expected);
   }
 
   @Test
-  public void testExample8() throws Exception {
+  void example8() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example8.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/filters/SuppressWithNearbyTextFilterExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/filters/SuppressWithNearbyTextFilterExamplesTest.java
@@ -24,70 +24,70 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class SuppressWithNearbyTextFilterExamplesTest extends AbstractExamplesModuleTestSupport {
+final class SuppressWithNearbyTextFilterExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/filters/suppresswithnearbytextfilter";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example7.txt"), expected);
   }
 
   @Test
-  public void testExample8() throws Exception {
+  void example8() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example8.txt"), expected);
   }
 
   @Test
-  public void testExample9() throws Exception {
+  void example9() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example9.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/filters/SuppressWithPlainTextCommentFilterExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/filters/SuppressWithPlainTextCommentFilterExamplesTest.java
@@ -24,7 +24,7 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class SuppressWithPlainTextCommentFilterExamplesTest
+final class SuppressWithPlainTextCommentFilterExamplesTest
     extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
@@ -32,56 +32,56 @@ public class SuppressWithPlainTextCommentFilterExamplesTest
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example7.txt"), expected);
   }
 
   @Test
-  public void testExample8() throws Exception {
+  void example8() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example8.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/filters/SuppressionCommentFilterExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/filters/SuppressionCommentFilterExamplesTest.java
@@ -24,63 +24,63 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class SuppressionCommentFilterExamplesTest extends AbstractExamplesModuleTestSupport {
+final class SuppressionCommentFilterExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/filters/suppressioncommentfilter";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example7.txt"), expected);
   }
 
   @Test
-  public void testExample8() throws Exception {
+  void example8() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example8.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/filters/SuppressionSingleFilterExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/filters/SuppressionSingleFilterExamplesTest.java
@@ -24,77 +24,77 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class SuppressionSingleFilterExamplesTest extends AbstractExamplesModuleTestSupport {
+final class SuppressionSingleFilterExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/filters/suppressionsinglefilter";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example7.txt"), expected);
   }
 
   @Test
-  public void testExample8() throws Exception {
+  void example8() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example8.txt"), expected);
   }
 
   @Test
-  public void testExample9() throws Exception {
+  void example9() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example9.txt"), expected);
   }
 
   @Test
-  public void testExample10() throws Exception {
+  void example10() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example10.txt"), expected);
--- a/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/filters/SuppressionXpathSingleFilterExamplesTest.java
+++ b/src/xdocs-examples/java/com/puppycrawl/tools/checkstyle/filters/SuppressionXpathSingleFilterExamplesTest.java
@@ -24,105 +24,105 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 @Disabled("until https://github.com/checkstyle/checkstyle/issues/13345")
-public class SuppressionXpathSingleFilterExamplesTest extends AbstractExamplesModuleTestSupport {
+final class SuppressionXpathSingleFilterExamplesTest extends AbstractExamplesModuleTestSupport {
   @Override
   protected String getPackageLocation() {
     return "com/puppycrawl/tools/checkstyle/filters/suppressionxpathsinglefilter";
   }
 
   @Test
-  public void testExample1() throws Exception {
+  void example1() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example1.txt"), expected);
   }
 
   @Test
-  public void testExample2() throws Exception {
+  void example2() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example2.txt"), expected);
   }
 
   @Test
-  public void testExample3() throws Exception {
+  void example3() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example3.txt"), expected);
   }
 
   @Test
-  public void testExample4() throws Exception {
+  void example4() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example4.txt"), expected);
   }
 
   @Test
-  public void testExample5() throws Exception {
+  void example5() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example5.txt"), expected);
   }
 
   @Test
-  public void testExample6() throws Exception {
+  void example6() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example6.txt"), expected);
   }
 
   @Test
-  public void testExample7() throws Exception {
+  void example7() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example7.txt"), expected);
   }
 
   @Test
-  public void testExample8() throws Exception {
+  void example8() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example8.txt"), expected);
   }
 
   @Test
-  public void testExample9() throws Exception {
+  void example9() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example9.txt"), expected);
   }
 
   @Test
-  public void testExample10() throws Exception {
+  void example10() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example10.txt"), expected);
   }
 
   @Test
-  public void testExample11() throws Exception {
+  void example11() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example11.txt"), expected);
   }
 
   @Test
-  public void testExample12() throws Exception {
+  void example12() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example12.txt"), expected);
   }
 
   @Test
-  public void testExample13() throws Exception {
+  void example13() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example13.txt"), expected);
   }
 
   @Test
-  public void testExample14() throws Exception {
+  void example14() throws Exception {
     final String[] expected = {};
 
     verifyWithInlineConfigParser(getPath("Example14.txt"), expected);